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Seven Scientific Facts Testify that Mohamed is Sincere
The most beautiful moments in the life of the believer when he see a miracle in the sayings of the prophet (Peace be upon him), we are in the era of science and scientific explorations, so we have to make some searching in his sayings to realize these scientific signs which testify that prophet Mohamed (Peace be upon him) is sincere. This research may make a good contribution to correct west vision about that illiterate prophet (Peace be upon him).
First Fact
Prophet Mohamed says to his companions :(this subject will reach all places the same as night and day) which means that Islam will spread to reach all places the same as night and day reach every place on earth . Indeed, today statistics says that religion of Islam is in every place in the world!! As these statistics says that by the year 2025 , Islam will be the first religion all over the world according to number of followers , this is not an exaggerated saying with no doubt these numbers are real , as these figures came from non Muslim scientists.
Statistical experts confirm that Islam is the fastest growing religion and there are Muslims in all countries all over the world but with different ratios. The question, isn't this the same as what prophet Mohamed said to his companions 1400 years ago?
Second Fact
The prophet said (ground was made for me as a place to prayer and also a method to be pure) [Narrated by Muslim]. in a new research scientists discovered that there are Antibiotics in the soil of earth , these Antibiotics can clean up and kill the most obstinate kind of bacteria , which prove that soil is a Disinfectant. In a new study scientists said that there are some kinds of soil which can remove the most obstinate kind of bacteria. Today, scientists are looking for manufacturing a killer for the most obstinate kind of bacteria extracted from soil. After many tests in laboratory they found that during 24 hour soil can remove an entire colony of bacteria but the same colony had multiplied 45 times without mud.
Scientists discovered that soil contains antibiotics, and without this feature life would not continue because of viruses and bacteria that may reach human and may eliminate his life and destroy him, but god with his mercy put the cleansing feature to ensure the continuation of our life. We have to thank god for this blessing.
Third Fact
Prophet Mohamed spoke very carefully about a scientific fact realized by scientists few years ago. He said ( God will not held day of resurrection unless Arab land returns greens and rivers again ) [Narrated by Muslim.] scientifically, it was proved that one day the Arabian peninsula was full of greens and rivers as satellite photos confirm that there are buried rivers under the sand of Arab land , one of the great scientists of the American space agency (NASA) says that the taken photos for the desert had shown that one day this area was covered with rivers and lakes like Europe and one day in the future it will back again like the past.
NASA scientists confirms that one day desert of Rub ' Al Khali and the Arabian Peninsula was covered with rivers, forests and animals and they confirm that this land will back again like the past , as referenced by the prophetic Hadith.
Fourth Fact
The Prophetic Hadith about the straight way in Day of Resurrection is considered to be one of the scientific miracles in the prophetic Sunnah. In this Hadith the prophet says:( don't you see that the lightning comes and back in an eye blink) [Narrated by Muslim] .there is complete identification between our prophet saying and the most recent discovery concerning the lightning flash as scientists had found that the lightning flash happens when a ray of lightning get out of the cloud toward the ground and back again to the cloud! In that Hadith a sign that prophet
Mohamed (Peace be upon him) talked very carefully about phases of the lightning, and also he determined the time as it is the time of an eye blink!
Scientists had found that lightning has many phases and the most important phases are going down phase and going back phase. Time of the lightning flash is 25 Fraction of a second and this is the same as time of eye blink, isn't this the same as what prophet Mohamed said 1400 years ago?
Fifth fact
Recently, scientists had discovered that forelock area (upper and front of the brain) controls right decisions making, so as long as this are is active and efficient ,the taken decisions would be more accurate and wise .prophet Mohamed (Peace be upon him) says in his supplication (oh god, my forelock is between your hand) [Narrated by Ahmed].in this supplication there is a full submission from the prophet to his god be he exalted as god is controlling however he wants and is predetermining whatever he wants . Also scientists discovered that forelock area plays a vital role in realizing, steering, problem solving and creation. So that prophet Mohamed had submitted this area for his god.
After long studies for brain activities, scientists had discovered that the most important area is the forelock (forepart of the head ) as this area is responsible for creation and steering operations so prophet Mohamed (Peace be upon him) confirms that this area is so important , and this is a miracle which testify that the prophet is sincere . How could he know about that issue in a time when no one knows anything about it? God taught him all of that as god says: (and taught you that which you knew not. And Ever Great is the Grace of Allah unto you) (An-Nisa'- verse 113)
Sixth Fact
Prophet Mohamed (Peace be upon him) said: (one of the signs of day of resurrection is the sudden death) [Narrated by AlTabarani]. Certainly, in this Hadith there is a scientific miracle concerning a medical fact which considered being a testimony that Mohamed is god's prophet. United Nations statistics confirms that phenomenon of sudden death appeared in recent days and is increasing despite all preventive procedures.
Heart doctors confirm that phenomenon of sudden death spread considerably in the last few years, despite the development in medicine and number of dead people by this phenomenon are increasing. Isn't this the same as what was indicated in the prophetic Hadith?
Seventh Fact
Most of scientists confirm that Senility is the best natural end for human, and any attempt to prolong life above certain limit will cause many effects, one of these effects is cancer. "Lee silver" from Princeton, the American University says:" any attempt to reach immortality is an opposite way against nature". So, it was useless to spend money to treat senility as the spent money was about millions of Dollars. this is the same as what prophet Mohamed (Peace be upon him) said :(oh you ,slaves of God you have to treat yourselves from ills , as each ill has a treatment except Senility , it has no treatment.) [Narrated by Ahmed]
So science gives us some new facts to verify and prove the truthfulness of the prophet and message of Islam.
Top 10 Ridiculously Common Science Myths
There is nothing better than a bit of mythbusting (which accounts for the popularity of the television program of the same name), so here we are again, presenting you with a new list of terribly common misconceptions and myths – this time about science.
The Myth: Evolution causes something to go from "lower" to "higher"
While it is a fact that natural selection weeds out unhealthy genes from the gene pool, there are many cases where an imperfect organism has survived. Some examples of this are fungi, sharks, crayfish, and mosses – these have all remained essentially the same over a great period of time. These organisms are all sufficiently adapted to their environment to survive without improvement.
Other taxa have changed a lot, but not necessarily for the better. Some creatures have had their environments changed and their adaptations may not be as well suited to their new situation. Fitness is linked to their environment, not to progress. [Source]
The Myth: When exposed to the vacuum of space, the human body pops
This myth is the result of science fiction movies which use it to add excitement or drama to the plot. In fact, a human can survive for 15 – 30 seconds in outer space as long as they breathe out before the exposure (this prevents the lungs from bursting and sending air into the bloodstream). After 15 or so seconds, the lack of oxygen causes unconsciousness which eventually leads to death by asphyxiation.
The Myth: Polaris is the brightest star in the northern hemisphere night sky
Sirius is actually brighter with a magnitude of ?1.47 compared to Polaris' 1.97 (the lower the number the brighter the star). The importance of Polaris is that its position in the sky marks North – and for that reason it is also called the "North Star". Polaris is the brightest star in the constellation Ursa Minor and, interestingly, is only the current North Star as pole stars change over time because stars exhibit a slow continuous drift with respect to the Earth's axis.
The Myth: Food that drops on the floor is safe to eat if you pick it up within five seconds
This is utter bunkum which should be obvious to most readers. If there are germs on the floor and the food lands on them, they will immediately stick to the food. Having said that, eating germs and dirt is not always a bad thing as it helps us to develop a robust immune system. I prefer to have a "how-tasty-is-it" rule: if it is something really tasty, it can sit there for ten minutes for all I care – I will still eat it.
The Myth: There is a dark side of the moon
Actually – every part of the moon is illuminated at sometime by the sun. This misconception has come about because there is a side of the moon which is never visible to the earth. This is due to tidal locking; this is due to the fact that Earth's gravitational pull on the moon is so immense that it can only show one face to us. Wikipedia puts it rather smartly thus: "Tidal locking occurs when the gravitational gradient makes one side of an astronomical body always face another; for example, one side of the Earth's Moon always faces the Earth. A tidally locked body takes just as long to rotate around its own axis as it does to revolve around its partner. This synchronous rotation causes one hemisphere constantly to face the partner body."
The Myth: Brain cells can't regenerate – if you kill a brain cell, it is never replaced
The reason for this myth being so common is that it was believed and taught by the science community for a very long time. But in 1998, scientists at the Sweden and the Salk Institute in La Jolla, California discovered that brain cells in mature humans can regenerate. It had previously been long believed that complex brains would be severely disrupted by new cell growth, but the study found that the memory and learning center of the brain can create new cells – giving hope for an eventual cure for illnesses like Alzheimer's.
The Myth: A penny dropped from a very high building can kill a pedestrian below
This myth is so common it has even become a bit of a cliche in movies. The idea is that if you drop a penny from the top of a tall building (such as the Empire State Building) – it will pick up enough speed to kill a person if it lands on them on the ground. But the fact is, the aerodynamics of a penny are not sufficient to make it dangerous. What would happen in reality is that the person who gets hit would feel a sting – but they would certainly survive the impact.
3. Friction Heat
The Myth: Meteors are heated by friction when entering the atmosphere
When a meteoroid enters the atmosphere of the earth (becoming a meteor), it is actually the speed compressing the air in front of the object that causes it to heat up. It is the pressure on the air that generates a heat intense enough to make the rock so hot that is glows brilliantly for our viewing pleasure (if we are lucky enough to be looking in the sky at the right time). We should also dispel the myth about meteors being hot when they hit the earth – becoming meteorites. Meteorites are almost always cold when they hit – and in fact they are often found covered in frost. This is because they are so cold from their journey through space that the entry heat is not sufficient to do more than burn off the outer layers.
The Myth: Lightning never strikes the same place twice
Next time you see lightning strike and you consider running to the spot to protect yourself from the next bolt, remember this item! Lightning does strike the same place twice – in fact it is very common. Lightning obviously favors certain areas such as high trees or buildings. In a large field, the tallest object is likely to be struck multiple times until the lightning moves sufficiently far away to find a new target. The Empire State Building gets struck around 25 times a year.
The Myth: There is no gravity in space
In fact, there is gravity in space – a lot of it. The reason that astronauts appear to be weightless because they are orbiting the earth. They are falling towards the earth but moving sufficiently sideways to miss it. So they are basically always falling but never landing. Gravity exists in virtually all areas of space. When a shuttle reaches orbit height (around 250 miles above the earth), gravity is reduced by only 10%.
5 Top Ways to Boost Your Immune Health and Stay Flu-Free
If you want to join the ranks of "those people" who rarely get sick, start with the strategies listed below. This is by no means an exhaustive list, but it does give you a general idea of how to live healthy and avoid getting sick. Other factors, like getting high-quality sleep and avoiding exposure to environmental toxins, are important too, but if you're looking for a few simple "secrets" to get started on today … start with these …
- Optimize Your Vitamin D
This takes the number one position for a reason: if you're vitamin-D-deficient, and many are, your immune system will not activate to do its job. Just one example of an important gene that vitamin D up-regulates is your ability to fight infections, including the flu. It produces over 200 antimicrobial peptides, the most important of which is cathelicidin, a naturally occurring broad-spectrum antibiotic.
At least five studies show an inverse association between lower respiratory tract infections and vitamin D levels. That is, the higher your vitamin D level, the lower your risk of contracting colds, flu, and other respiratory tract infections. To find out more, including your best sources of vitamin D, dosing and what proper levels should be, please watch my free one-hour lecture.
The best way to increase your vitamin D level is by sun exposure but that is difficult for most people in the fall and winter, so next best would be to use a safe tanning bed. Neither of these methods require blood testing as long as you are getting enough exposure to get a tan. The least best way to increase your vitamin D level is by swallowing it, which will require a blood test to confirm your level is correct. Most adults require 8,000 units to reach therapeutic levels and some much more. Although that may sound too high to some, remember you can get up to 20,000 units through sun or tanning bed exposures.
- Optimize Your Insulin and Leptin Levels by Avoiding Sugar, Fructose
Eating sugar, fructose and grains will increase your insulin level, which is one of the fastest ways to get sick and also experience premature aging. Leptin is another heavyweight hormone associated with disease and the aging process.
Like your insulin levels, if your leptin levels become elevated, your body systems will develop a resistance to this hormone, which will wreak havoc in your body.
My nutrition plan, based on natural whole foods, is your first step toward optimizing your insulin and leptin levels and increasing your chances of living a longer, healthier life. The heart of my program is the elimination, or at the very least, drastic reduction of fructose, grains and sugar in your diet, which is also important for flu prevention because sugar decreases the function of your immune system.
- Exercise
If you are exercising regularly, just as if your vitamin D levels are optimized, the likelihood of your acquiring the flu or other viral illness decreases quite dramatically, and studies have clearly shown this.
In one such study, staying active cut the risk of having a cold by 50 percent, and cut the severity of symptoms by 31 percent among those who did catch a cold. The researchers noted that each round of exercise may lead to a boost in circulating immune system cells that could help ward off a virus.
It's a well-known fact that exercise improves the circulation of immune cells in your blood. The job of these cells is to neutralize pathogens throughout your body. The better these cells circulate, the more efficient your immune system is at locating and defending against viruses and diseases trying to attack your body.
Since exercise has repeatedly been proven to benefit your immune system over the long haul, it's crucial to treat exercise like a drug that must be properly prescribed, monitored and maintained for you to enjoy the most benefits. Essentially, you need to have a varied, routine that includes high-intensity interval exercises like Peak Fitness.
- Eat Plenty of Raw Food
One of the most important aspects of a healthy diet that is frequently overlooked is the issue of eating your food uncooked, in its natural raw state.
Unfortunately, as you may be aware, over 90 percent of the food purchased by Americans is processed. And when you're consuming these kinds of denatured and chemically altered foods, it's no surprise we have an epidemic of chronic and degenerative diseases, not to mention way too many cases of colds and flu.
Ideally you'll want to eat as many foods as possible in their unprocessed state; typically organic, biodynamic foods that have been grown locally, and are therefore in season. But even when you choose the best foods available you can destroy most of the nutrition if you cook them. I believe it's really wise to strive to get as much raw food in your diet as possible.
I personally try to eat about 80 percent of my food raw, including raw eggs and organic, naturally raised meats.
- Learn How to Effectively Cope With Stress
Stress has a major influence on the function of your immune system, which is why you've probably noticed you're more likely to catch a cold or the flu when you're under a lot of stress. This is true for both acute stressful episodes, such as preparing a big project for work, and chronic stress, such as relationship troubles or grief. Both will deteriorate your immune system and leave it less able to fight off infectious agents.
And, in the event you do get sick, emotional stressors can actually make your cold and flu symptoms worse. So be sure you take time in life to de-stress and unwind using stress management tools like exercise, meditation, massage, and solid social support.
Insect Fact You Should Know – Top 10 Gruesome Insect Facts!
Small but terrible. That's what insects are. Indeed, most insects can fit in the palm of your hand and yet, they can also result in the biggest fears, with even adults screaming at the sight of them. Don't think they're creepy? Well, these ten facts may just change your mind.
1. A cockroach can live for weeks without its head.
Cockroaches are some of the creepiest insects around for two main reasons. One, they carry tons of bacteria that can cause harmful diseases and two, they are so hard to kill. And we mean hard. A cockroach can live for weeks without food and water. They can hold their breath for up to 40 minutes which means flushing them down the toilet isn't a surefire way to kill them. And they can even survive a nuclear explosion.
Not convinced about how hardy cockroaches are? Well, take this – cockroaches can live weeks without their heads. So don't be surprised if you see a headless cockroach crawling around (even though you might just feel like screaming). This is because cockroaches don't need their brains to breathe or move. Those functions are controlled by organs found in other parts of their body. They also won't bleed to death like we would when our heads are cut. The wound would just clot like any other wound.
This doesn't mean, though, that cockroaches are immortal. They will still die eventually from hunger and thirst since they need their heads to eat and drink.
Oh, and one more thing. A cockroach head can also survive on its own for several hours or even days if it's refrigerated. Now, what's more gruesome? A headless cockroach or a moving cockroach head?
2. Honey bees have hair on their eyeballs.
Honey bees have one of the best eyesights in the insect world. They have five eyes, two of which are compound, meaning they are made up of thousands of smaller eyes. These compound eyes are so efficient, they can see up to 300 frames per second and they can also see ultraviolet light.
That's amazing but here's something creepy about the eyes of honey bees. They have hair. The fine hairs help the bees to pick up and transfer more pollen. Also, they can help the bees tell the direction of the wind and to detect the humidity in the air.
3. In some parts of the world, army ants are used to close wounds.
Some army ants have such powerful mandibles that when they bite you, you'll really scream from the pain. Some won't even let go of your skin even after they're dead, leaving behind nasty puncture wounds.
Their strong jaws are not always harmful, though. In East Africa and parts of the Amazon, army ants are used to close the wounds. In the case of a bad cut, they get army ants to bite both sides of the cut, holding the skin together. This effectively stops the bleeding, much like stitches do and can hold for up to a few days, allowing the wound to heal. This practice is so effective it has been around since 1000 BC.
4. Some caterpillars disguise themselves as bird poop.
Caterpillars are a favorite snack of birds so to protect themselves, they've taken on various appearances. Some look like twigs. Others look like snake heads and the puss moth has a unique, startling appearance altogether.
Then there are the caterpillars that disguise themselves as bird poop such as the white admiral, the giant swallowtail, the Asian swallowtail and the viceroy caterpillars. They are black or gray with tinges of yellow and white, just like bird poop, and some of them are even slightly dangling off a branch or a leaf, making them look more convincing. And it works! Studies show that birds are three times less likely to attack a hanging bird poop-looking caterpillar than a straight one.
5. Female praying mantises eat their mates.
Not always. Sometimes, if the male is lucky enough, he can run for it and survive. If he's out of luck, though, the larger and stronger female will end up eating him. Head first. In fact, some females start eating the heads of the males even before mating. Amazingly, he's still able to get the job done but he won't be going anywhere afterwards.
Why does the female praying mantis do this? Easy. She's just hungry. Praying mantises are ferocious hunters, after all.
6. Twisted-wing parasite larvae eat their mother.
What's worse than eating your own mate? Probably eating your own mother, which is exactly what the twisted-wing parasite larvae do.
These tiny insects live inside bees, wasps and cockroaches. The adult males grow wings and eventually leave the host to find females to mate with but the females, once inside a host, never leave, simply sticking their butts out of the host so that they can be mated with. After mating, the females get pregnant and when the babies are ready to come out, they eat their mother from the inside, bursting out of her brood canal. Now, that's a painful birth. Eventually, the larvae develop legs and they crawl out of the host to find a new one where they will grow and develop into adults. And the cycle starts all over again.
7. House flies poop constantly.
See that fly perched on the wall or at the edge of your table? It's probably pooping.
House flies eat a lot of food but they can't take it all in or they wouldn't be able to fly, so they're also constantly pooping. Oh, and they regularly vomit, too. That's because they can't chew solid food. When they find solid food, like a slice of bread, for example, what they do is that they vomit on it in order to soften it and when it becomes soft enough, they suck it all in, vomit and food and all.
So the next time you see a fly land on something you're eating, forget about putting it inside your mouth. The fly might have already pooped on it or threw up on it – and your guess is as good as anyone's as to what meal it ate last. Even if it didn't, keep in mind that a single house fly can carry up to 30 million bacteria, 6 million on its legs that touched your food! Yuck!
8. Leaf beetle larvae have shields made of poop.
Speaking of poop, the larvae of various species of leaf beetles have found a use for theirs. They use them to make shields – fecal shields. These shields act not just as physical barriers like the shields warriors use but also act as chemical barriers, filled with chemical compounds that repel other insects that might think of eating them. The shape and size of the shield varies among species, with some stuck to the larva's back or held up by the larva like an umbrella. Either way, the larva needs a lot of energy to carry the shield, which can weigh up to half its own weight.
9. Assassin bugs suck the insides of their prey.
Assassin bugs are well-named. They sneak up to other insects – caterpillars, beetles, flies, bees, crickets, cockroaches – even those larger than they are and then they stab it with their long straw-like mouth, injecting a good amount of their saliva. The saliva is toxic and turns the insides of the insect into liquid, allowing the assassin bug to gradually suck them out, leaving behind the empty, lifeless shell. Sometimes, they even start sucking the insides of their prey while it is still alive, holding it down using their hairy legs.
Assassin bugs can be beneficial because they feed on pests. However, they can also be harmful. Some assassin bugs can deliver a very painful bite when picked up while others can transmit Chaga's Disease, which kills about 13,000 people each year in Central and South America.
10. Voodoo wasps turn caterpillars into their bodyguards.
The voodoo wasp is another insect that lives up to its name. You see, female voodoo wasps lay their eggs inside a caterpillar's body. After the eggs hatch, the pupae crawl out of the caterpillar. The caterpillar appears dead, unmoving, but watch when a predator such as another bug comes near. Suddenly, the caterpillar wildly thrashes about as if a spell has been cast upon it. The result? The predator leaves and the pupae are safe. In essence, the caterpillar has not only become the living nursery for the pupae, but it is also transformed into their bodyguard, a process scientists have yet to explain. (Who knows? Maybe wasps can practice voodoo.)
Human Embryonic Development in The Quran
In the Holy Quran, God speaks about the stages of man's embryonic development:
"We created man from an extract of clay. Then We made him as a drop in a place of settlement, firmly fixed. Then We made the drop into an alaqah (leech, suspended thing, and blood clot), then We made the alaqah into a mudghah (chewed substance)…" (Quran 23:12-14)
Literally, the Arabic word alaqah has three meanings: (1) leech, (2) suspended thing, and (3) blood clot.
In comparing a leech to an embryo in the alaqah stage, we find similarity between the two as we can see in figure 1. Also, the embryo at this stage obtains nourishment from the blood of the mother, similar to the leech, which feeds on the blood of others.
Figure 1: Drawings illustrating the similarities in appearance between a leech and a human embryo at the alaqah stage. (Leech drawing from Human Development as Described in the Quran and Sunnah, Moore and others, p. 37, modified from Integrated Principles of Zoology, Hickman and others. Embryo drawing from The Developing Human, Moore and Persaud, 5th ed., p. 73.)
The second meaning of the word alaqah is "suspended thing." This is what we can see in figures 2 and 3, the suspension of the embryo, during the alaqah stage, in the womb of the mother.
Figure 2: We can see in this diagram the suspension of an embryo during the alaqah stage in the womb (uterus) of the mother. (The Developing Human, Moore and Persaud, 5th ed., p. 66.)
Figure 3: In this photomicrograph, we can see the suspension of an embryo (marked B) during the alaqah stage (about 15 days old) in the womb of the mother. The actual size of the embryo is about 0.6 mm. (The Developing Human, Moore, 3rd ed., p. 66, from Histology, Leeson and Leeson.)
The third meaning of the word alaqah is "blood clot." We find that the external appearance of the embryo and its sacs during the alaqah stage is similar to that of a blood clot. This is due to the presence of relatively large amounts of blood present in the embryo during this stage (see figure 4). Also during this stage, the blood in the embryo does not circulate until the end of the third week. Thus, the embryo at this stage is like a clot of blood.
Figure 4: Diagram of the primitive cardiovascular system in an embryo during the alaqah stage. The external appearance of the embryo and its sacs is similar to that of a blood clot, due to the presence of relatively large amounts of blood present in the embryo. (The Developing Human, Moore, 5th ed., p. 65.)
So the three meanings of the word alaqah correspond accurately to the descriptions of the embryo at the alaqah stage.
The next stage mentioned in the verse is the mudghah stage. The Arabic word mudghah means "chewed substance." If one were to take a piece of gum and chew it in his or her mouth and then compare it with an embryo at the mudghah stage, we would conclude that the embryo at the mudghah stage acquires the appearance of a chewed substance. This is because of the somites at the back of the embryo that "somewhat resemble teethmarks in a chewed substance." (see figures 5 and 6).
Figure 5: Photograph of an embryo at the mudghah stage (28 days old). The embryo at this stage acquires the appearance of a chewed substance, because the somites at the back of the embryo somewhat resemble teeth marks in a chewed substance. The actual size of the embryo is 4 mm. (The Developing Human, Moore and Persaud, 5th ed., p. 82, from Professor Hideo Nishimura, Kyoto University, Kyoto, Japan.)
Figure 6: When comparing the appearance of an embryo at the mudghah stage with a piece of gum that has been chewed, we find similarity between the two.
A) Drawing of an embryo at the mudghah stage. We can see here the somites at the back of the embryo that look like teeth marks. (The Developing Human, Moore and Persaud, 5th ed., p. 79.)
B) Photograph of a piece of gum that has been chewed.
How could Muhammad, may the mercy and blessings of God be upon him, have possibly known all this 1400 years ago, when scientists have only recently discovered this using advanced equipment and powerful microscopes which did not exist at that time? Hamm and Leeuwenhoek were the first scientists to observe human sperm cells (spermatozoa) using an improved microscope in 1677 (more than 1000 years after Muhammad). They mistakenly thought that the sperm cell contained a miniature preformed human being that grew when it was deposited in the female genital tract.
Professor Emeritus Keith L. Moore is one of the world's most prominent scientists in the fields of anatomy and embryology and is the author of the book entitled The Developing Human, which has been translated into eight languages. This book is a scientific reference work and was chosen by a special committee in the United States as the best book authored by one person. Dr. Keith Moore is Professor Emeritus of Anatomy and Cell Biology at the University of Toronto, Toronto, Canada. There, he was Associate Dean of Basic Sciences at the Faculty of Medicine and for 8 years was the Chairman of the Department of Anatomy. In 1984, he received the most distinguished award presented in the field of anatomy in Canada, the J.C.B. Grant Award from the Canadian Association of Anatomists. He has directed many international associations, such as the Canadian and American Association of Anatomists and the Council of the Union of Biological Sciences.
In 1981, during the Seventh Medical Conference in Dammam, Saudi Arabia, Professor Moore said: "It has been a great pleasure for me to help clarify statements in the Quran about human development. It is clear to me that these statements must have come to Muhammad from God, because almost all of this knowledge was not discovered until many centuries later. This proves to me that Muhammad must have been a messenger of God."
Consequently, Professor Moore was asked the following question: "Does this mean that you believe that the Quran is the word of God?" He replied: "I find no difficulty in accepting this."
During one conference, Professor Moore stated: "….Because the staging of human embryos is complex, owing to the continuous process of change during development, it is proposed that a new system of classification could be developed using the terms mentioned in the Quran and Sunnah (what Muhammad, may the mercy and blessings of God be upon him, said, did, or approved of). The proposed system is simple, comprehensive, and conforms with present embryological knowledge. The intensive studies of the Quran and hadeeth (reliably transmitted reports by the Prophet Muhammad's companions of what he said, did, or approved of) in the last four years have revealed a system for classifying human embryos that is amazing since it was recorded in the seventh century A.D. Although Aristotle, the founder of the science of embryology, realized that chick embryos developed in stages from his studies of hen's eggs in the fourth century B.C., he did not give any details about these stages. As far as it is known from the history of embryology, little was known about the staging and classification of human embryos until the twentieth century. For this reason, the descriptions of the human embryo in the Quran cannot be based on scientific knowledge in the seventh century. The only reasonable conclusion is: these descriptions were revealed to Muhammad from God. He could not have known such details because he was an illiterate man with absolutely no scientific training."
6 Great Things on Microbes
1. Microbes play defense. The oodles of microbes that live on and inside us protect us from pathogens simply by taking up space. By occupying spots where nasties could get access to and thrive, good microbes keep us healthy. As Eisen explains, "It's sort of like how having a nice ground cover around your house can prevent weeds from taking over."
2. Microbes boost the immune system. Researchers at Loyola University demonstrated in a 2010 study how Bacillus, a rod-shaped bacteria found in the digestive tract, bind to immune system cells and stimulate them to divide and reproduce. The research suggests that, years down the road, those with weakened immune systems could be treated by introducing these bacterial spores into the system. These microbes could potentially even help the body fight cancerous tumors.
3. Microbes protect us from auto-immune diseases. In his TEDTalk, Eisen describes being diagnosed with Type 1 Diabetes as a teenager after "slowly wasting away until I looked like a famine victim with an unquenchable thirst." Because microbes help train the immune system, if the microbiome is thrown out of whack, it can alter the body's ability to differentiate between itself and foreign invaders. Recent research into Type 1 Diabetes reveals that a disturbance in the microbial community could trigger the disease, in which the body kills cells that produce insulin. In a 2009 study, researchers at Cornell University showed that introducing a benign strain of E. coli into diabetic mice set off a domino effect that led them to produce insulin. The work suggests that, someday, microbial yogurt could replace insulin shots for people with the disease. Microbial disturbances could be at the root of other auto-immune disorders too.
4. Microbes keep us slim. Microbes play an important role in our body shape by helping us digest and ferment foods, as well as by producing chemicals that shape our metabolic rates. Eisen explains, "It seems that disturbances in our microbial community may be one of the factors leading to an increase in obesity."
5. Microbes detoxify and may even fight off stress. Just as humans breath in oxygen and release carbon dioxide, microbes in and on us take in toxins and spare us their dangerous effects. A recent study also shows that people feeling intense stress have much less diverse bacterial communities in the gut, suggesting that there is a not-yet-understood interplay between microbes and stress responses.
6. Microbes keep babies healthy. Recent studies have shown that babies born via caesarean section have very different microbiomes than those born the old-fashioned way. Why? Because during the birthing process, babies are colonized with the microbes of their mother, especially substances that aid in the digestion of milk. According to Science News, babies born via C-section are more likely to develop allergies and asthma than children born vaginally.
When Did Insects Evolve?
In case you were wondering, at last count 1,659,420 species of animals have been described by scientists. Nearly 80% of those are arthropods, or insects and their crunchy relatives.
Our Planet of the Arthropods is dominated by insects, and when and how insects took over the earth is a question that's puzzled naturalists for centuries. In an incredible international effort, 100 scientists combined their molecular, computational biology, statistics, paleontology, and taxonomic expertise to uncover some surprising conclusions about when major groups of insects evolved:
B. Misof, et al. 2014. Phylogenomics resolves the timing and pattern of insect evolution. Science 346 (6210): 763-767.
How do you solve a problem like the insects?
The back story of this research is almost as interesting as the results. Making sense of the diversity of insects in collections has traditionally been a task for a lone expert, usually specializing in just one subset of a group. They become so identified with their study organisms, they may be introduced as "The Ant Man" or "The Wasp Woman." (No taxonomists I know wear spandex tights and capes to work, for which I am profoundly grateful.) With over a million described species, it's not hard to see how someone might spend an entire life trying to make order out of biodiversity chaos.
Taxonomy has a history of conflict and eccentricity, and the entry of new molecular technologies into the world of tiny pins and museum specimens hasn't always been smooth. When sequencing was expensive and time consuming, the question was "which species should we do next?" Competition for funding and lab space was brisk.
With advances in both computing and Next-Generation sequencing, the speed and cost of sequencing dropped enough that scientists can band together and ask bigger questions. Brian Wiegmann of North Carolina State University (Author #74) put this elegantly: "It's not enough to just catalog the books in the library; we want to understand their contents."
Bernhard Misof from the Zoological Research Museum Alexander Koenig, Germany (Author #1), Xin Zhou from the China National GeneBank, BGI-Shenzhen, China (Author #100), and Karl Kjer from Rutgers University, USA (Author #99), came up with an ambitious plan. They formed 1KITE; the acronym stands for 1K Insect Transcriptome Evolution. A global crew of experts was recruited to help create an open-access inventory of transcriptomes (all expressed genes in an organism) for 1,000 insect species. This database will be used to answer questions about how insects evolved into the amazing diversity of forms we see today, and also has applications in medicine, agriculture, and conservation ecology.
The paper released this week deals mostly with the timing of insect evolution, based on a subset of 144 species. The researchers are looking for answers to some very big questions: When did insects evolve flight? When did the amazing diversity of insects develop?
Clocks and Rocks
The problem with fossils is they are rare. When you have tiny squishy animals involved, they are even less common. This new research uses time estimates based on geological evidence from fossils in combination with estimated times of divergence based on molecular evidence. This is sometimes called a molecular clock, since it uses accumulated changes in DNA to tell how much time has passed.
Looking at all the RNA in thousands of insect samples in hundreds of species of insects is a LOT of data. The biggest problem for the project was dealing with the massive amount of sequence information generated. The possible combinations were in the quadrillions. The computing capacity to crunch all that data…doesn't exist.
This is where computer scientist and bioinformatics expert Alexandros Stamatatakis (Author #60) and his team came into play. His research group came up with a mathematical method to exclude highly unlikely combinations, and focus on likely ones. The Heidelberg Institute for Theoretical Studies Supercomputer group, which usually works on astrophysics problems, was used to crunch the data.
Dinosaurs did not have lice, and other revelations
So what did this tremendous amount of work find? The conclusion I think will stir up the most public attention is that lice are a recent group of insects, appearing only about 53 million years ago; the time that modern birds and mammals showed up.
This date makes lice "younger" than primates. There may be a bit of a kerfuffle as previous lousy estimates based on fossils are revised. Everyone loves a good taxonomic throwdown.
But that is really a secondary finding. Other major findings of note:
- Insect ancestors (Hexapoda) likely originated during the Early Ordovician Period, about 479 million years ago.
- Insect flight emerged around 406 million years ago, around the same time plants began to really diversify on land and grow upward into forests.
- The explosive diversification of insects into most of the major orders we see today happened before the emergence of Angiosperms (flowering plants).
Just how very fast insects diversified is remarkable. The earth is ~4.5 billion years old. In just the last 10% of earth's history, plants colonized the land. In a span of 80 million years insects formed most of the major groups still alive today and took over the skies, where they reigned supreme for millennia.
Jessica Ware of Rutgers University (Author #8) said "it was a rapid and extreme radiation in a very short period of time. It made our job really hard as scientists–that's been one of the traditional stumbling blocks for classifying insects. With this huge amount of data we now have excellent resolution, and we can actually say something about age ranges."
What Does It All Mean?
The best part of this research is yet to come, but where we are headed is clear. The Insect tree of life has been pruned and re-arranged constantly in the last century. It sometimes feels like taxonomists have been participating in an FBI witness-protection program, the names have been changed so often.
That will certainly continue — understanding how each group of beetles, for example, is related is a very fine level of detail. But the bigger picture is finally coming into focus. We now are on track to a real phylogeny, or map of what came first, and what relationship groups have with each other. This group is a parent, this group is a sister.
As more of the research from this group is published, we are getting closer to a phylogeny of insects that is more than just a story that we pieced together from wing patterns and bug genitals. We are truly beginning to realize what a great beetle collector once said:
The First Dinosaurs
About 230 million years ago–give or take a few million years–the first dinosaurs evolved from the archosaurs, the "ruling lizards" that shared the earth with other families of early reptiles, including therapsids and pelycosaurs. As a group, dinosaurs are defined by a host of (mostly obscure) anatomical features, but to simplify matters a bit, the main thing that distinguished them from their archosaur forebears was their erect posture (either bipedal or quadrupedal), as evidenced by the shape and arrangement of their hip and leg bones.
As with all such evolutionary transitions, it's impossible to identify the exact moment when the first dinosaur walked the earth: for a few million years during the middle Triassic period, some reptile species would have evinced a confusing mixture of archosaur and dinosaur characteristics. For example, the two-legged archosaur Marasuchus (sometimes identified as Lagosuchus) looked remarkably like an early theropod dinosaur, and along with genera like Saltopus and Procompsognathus may well have inhabited that in-between "shadow zone" that has proven so baffling to paleontologists. (The recent discovery of a new genus of archosaur, Asilisaurus, may push back the dinosaur family tree even further, to 240 million years ago; the implications of this are still being sorted out, as are the implications of dinosaur-like footprints in Europe dating as far back as 250 million years ago!.)
South America – Land of the First Dinosaurs
Over the past few decades, the earliest of what have been conclusively identified as the first true dinosaurs have been found at fossil sites in South America.
Until recently, the most famous of these were the relatively large (about 400 pounds) Herrerasaurus and the medium-sized (about 75 pounds) Staurikosaurus, both of which lived about 230 million years ago and seem to have been genuine theropods. Most of the buzz has now shifted to Eoraptor, discovered in 1991, a tiny (about 20 pounds) South American theropod whose plain-vanilla appearance would have made it a perfect template for later dinosaur specialization (by some accounts, Eoraptor may actually have been ancestral to sauropods rather than more advanced theropods).
(A recent discovery may overturn our thinking about the South American origin of the first dinosaurs. In December of 2012, paleontologists announced the discovery of Nyasasaurus, which lived in a region of Pangaea corresponding to present-day Tanzania, in Africa. Shockingly, this slim dinosaur dates to 243 million years ago, or about 10 million years before the putative first South American dinosaurs. Still, it may yet turn out that Nyasasaurus and its relatives represented a short-lived offshoot of the early dinosaur family tree, or that it was technically an archosaur rather than a dinosaur.)
These three early theropods spawned a hardy breed that quickly (at least in evolutionary terms) radiated out to other continents. The first dinosaurs quickly made their way into North America (the prime example is Coelophysis, hundreds of fossils of which have been discovered at Ghost Ranch in New Mexico) and a recent discovery, Tawa, which has been adduced as further evidence for the South American origin of dinosaurs. Small and medium-sized theropods soon made their way to eastern North America (Podokesaurus), then onward to Africa and Eurasia (for example, the western European Liliensternus).
The Specialization of the First Dinosaurs
Theropod dinosaurs accounted for a small (but disproportionately popular) percentage of all the dinosaurs that ever lived; over the Jurassic and Cretaceous periods, these two-legged meat eaters radiated out into tyrannosaurs, raptors, dino-birds and a bewildering array of large theropods (such as Spinosaurus and Allosaurus). What about the herbivorous dinosaurs, which well outnumbered their carnivorous counterparts?
Here's where things get a bit more complicated. Technically, theropods are saurischian ("lizard-hipped") dinosaurs, a group that also included the giant, plant-eating sauropods of the late Jurassic and Cretaceous periods. These sauropods were preceded by the prosauropods (also known as "sauropodomorphs"), some of which looked remarkably like early theropods. The prosauropod family tree begins about 220 million years ago; early genera like Efraasia and Camelotia remain somewhat mysterious, but the breed is better attested to a few million years later with dinosaurs like Plateosaurus and Sellosaurus.
As for the ornithischian ("bird-hipped") dinosaurs–a family that includes ornithopods, hadrosaurs, ankylosaurs and ceratopsians–they can trace their ancestry all the way back to Eocursor, a small, theropod-like dinosaur from late Triassic South Africa. Eocursor itself would have ultimately derived from an equally small South American theropod, probably Eoraptor, that lived 20 million or so years earlier–demonstrating how the vast diversity of dinosaurs could have originated from such a humble progenitor.
Dino-Birds – The Small, Feathered Dinosaurs
Part of the reason so many ordinary people doubt the evolutionary link between feathered dinosaurs and birds is because when they think of the word "dinosaur," they picture enormous beasts like Brachiosaurus and Tyrannosaurus Rex, and when they think of the word "bird," they picture harmless, rodent-sized pigeons and robins (and perhaps the occasional eagle or penguin). See a gallery of feathered dinosaur pictures
Closer to the Jurassic and Cretaceous periods, though, the visual referents are a lot different. For decades, paleontologists have been digging up small, birdlike theropods (the same family of two-legged dinosaurs that includes tyrannosaurs and raptors) bearing unmistakable evidence of feathers, wishbones, and other bits of avian anatomy. Unlike larger dinosaurs, these smaller theropods tend to be unusually well-preserved, and many such fossils have been found completely intact (which is more than can be said for the average sauropod).
Feathered Dinosaurs, Birds and Evolution
What do these fossils tell us about the evolution of prehistoric birds from dinosaurs? Well, for starters, it's impossible to pin down a single "missing link" between these two types of animals. For a while, scientists believed the 150-million-year-old Archaeopteryx was the indisputable transitional form, but it's still not clear if this was a true bird (as some experts claim) or a very small, and not very aerodynamic, theropod dinosaur.
(In fact, a new study claims that the feathers of Archaeopteryx weren't strong enough to sustain extended bursts of flight.)
The problem is, the subsequent discovery of other small, feathered dinosaurs that lived at the same time as Archaeopteryx–such as Epidendrosaurus, Pedopenna and Xiaotingia–has muddied the picture considerably, and there's no ruling out the possibility that future paleontologists will unearth dino-birds from as far back as the Triassic period. In addition, it's far from clear that all these feathered theropods were closely related: evolution has a way of repeating its jokes, and feathers (and wishbones) may well have evolved multiple times.
To show how tricky this issue is, here's the standard picture of bird evolution: small, running theropods (for the sake of argument, let's say raptors) evolved feathers as a way of keeping warm and attracting mates. As these feathers grew larger and more ornate, they provided an unexpected bonus: a split-second of extra "lift" when their owner pounced on prey or ran away from larger predators. Multiply this scenario by countless generations, and you have a solid theory for the origin of avian flight.
Feathered Dinosaurs up in Trees
There are, however, a few complications with this story. Although the "ground up" theory of bird evolution is widely accepted by paleontologists, we have strong evidence that feathered dinosaurs like Scansoriopteryx and Microraptor spent most of their lives in trees. In addition, Microraptor appears to have had wings on both its front and back limbs–making it more like a gliding squirrel than a modern bird. Did feathered flight begin when these tree-dwelling dinosaurs' young accidentally fell out of the perch?
In any event, how do we know that these feathered dinosaurs led an arboreal (tree-dwelling) lifestyle? Paleontologists often abstract prehistoric behavior from the lifestyles of similarly proportioned modern creatures. For example, the long middle fingers of Epidendrosaurus look uncannily like the claws of some South American lemurs, whose sole function is to pry insects out of tree bark!
Too Many Feathered Dinosaurs
Another problem with tracing the exact course of dinosaur-bird evolution is that so many likely ancestors technically belonged to different families. While all feathered dinosaurs that we know of were true theropods, some are classified as raptors, some as oviraptors, some as troodonts, some as ornithomimids and some as, well, your guess is as good as the experts' (it's even possible that juvenile tyrannosaurs had a fine feather coating). The key thing is, all these creatures resembled each other more closely than they resembled the typical genera in their extended families (for example, Sinornithosaurus looks a lot more like the troodont Sinovenator than it does its fellow raptor Deinonychus).
Further complicating matters, the behavior of small, feathered dinosaurs seems to have been remarkably adaptable. Paleontologists have yet to discover any meat-eating ornithopods (these dinosaurs were strictly vegetarian), but at least two feathered "therizinosaur" theropods–Incisivosaurus and Falcarius–appear to have been plant eaters, and the large, ostrich-like ornithomimids were probably omnivorous.
The Feathered Dinosaurs of Liaoning
Every now and then, paleontologists stumble across a fossil treasure trove that forever changes the public's perception of dinosaurs. Such was the case in the early 1990's, when researchers uncovered rich fossil deposits in Liaoning, a northeastern province of China. All of the fossils date from about 130 million years ago, making Liaoning a spectacular window into the early Cretaceous period.
Although Liaoning has yielded fossilized insects, fish and mammals, among other creatures, it has become best known for its small, feathered dinosaurs. To date, paleontologists have uncovered dozens of exceptionally well-preserved fossils of feathered theropods, accounting for over a dozen separate genera. (You can often recognize a Liaoning dino-bird from its name; witness the "sino," meaning "Chinese," in Sinornithosaurus, Sinosauropteryx and Sinovenator.)
Since Liaoning's fossil deposits represent a mere snapshot in the long history of dinosaurs, their discovery has raised the possibility that more dinosaurs were feathered than scientists have ever dreamed–and that the evolution of dinosaurs into birds was not a one-time, linear process. In fact, it's very possible that dinosaurs evolved into what we would recognize as "birds" numerous times over the course of a hundred million years–with only one branch surviving into the modern era and yielding those familiar pigeons, sparrows, penguins and eagles.
Evolution of Fish in Million Years
Compared to dinosaurs, mammoths and saber-toothed cats, fish evolution may not seem all that interesting–until you realize that if it weren't for prehistoric fish, dinosaurs, mammoths and saber-toothed cats would never have existed. The first vertebrates on the planet, fish provided the basic "body plan" subsequently elaborated on by hundreds of millions of years of evolution: in other words, your great-great-great (multiply by a billion) grandmother was a small, meek fish of the Devonian period.
The Earliest Vertebrates: Pikaia and Pals
Although most paleontologists wouldn't recognize them as true fish, the first fish-like creatures to leave an impression on the fossil record appeared during the middle Cambrian period, about 530 million years ago. The most famous of these, Pikaia, looked more like a worm than a fish, but it had four features crucial to later fish (and vertebrate) evolution: a head distinct from its tail, bilateral symmetry (the left side of its body looked like the right side), V-shaped muscles, and most importantly, a nerve cord running down the length of its body. Because this cord wasn't protected by a tube of bone or cartilage, Pikaia was technically a "chordate" rather than a vertebrate, but it still lay at the root of the vertebrate family tree.
Two other Cambrian proto-fish were a bit more robust than Pikaia. Haikouichthys is considered by some experts–at least those not overly concerned by its lack of a calcified backbone–to be the earliest jawless fish, and this inch-long creature had rudimentary fins running along the top and bottom of its body.
The similar Myllokunmingia was slightly less elongated than either Pikaia or Haikouichthys, and it also had pouched gills and (possibly) a skull made of cartilage. (Other fish-like creatures may have predated these three genera by tens of millions of years; unfortunately, they haven't left any fossil remains.)
The Evolution of Jawless Fish
During the Ordovician and Silurian periods–from 490 to 410 million years ago–the world's oceans, lakes and rivers were dominated by jawless fish, so named because they lacked lower jaws (and thus the ability to consume large prey). You can recognize most of these prehistoric fish by the "-aspis" (the Greek word for "shield") in the second parts of their names, which hints at the second main characteristic of these early vertebrates: their heads were covered by tough plates of bony armor.
The most notable jawless fish of the Ordovician period were Astraspis and Arandaspis, six-inch-long, big-headed, finless fish that resembled giant tadpoles. Both of these species made their living by bottom-feeding in shallow waters, wriggling slowly above the surface and sucking up tiny animals and the waste of other marine creatures. Their Silurian descendants shared the same body plan, with the important addition of forked tail fins, which gave them more maneuverability.
If the "-aspis" fish were the most advanced vertebrates of their time, why were their heads covered in bulky, un-hydrodynamic armor? The answer is that, hundreds of millions of years ago, vertebrates were far from the dominant life forms in the earth's oceans, and these early fish needed a means of defense against giant "sea scorpions" and other large arthropods.
The Big Split: Lobe-Finned Fish, Ray-Finned Fish and Placoderms
By the start of the Devonian period–about 420 million years ago–the evolution of prehistoric fish veered off in two (or three, depending on how you count them) directions. One development, which wound up going nowhere, was the appearance of the jawed fishes known as placoderms ("plated skin"), the earliest identified example of which is Entelognathus. These were essentially larger, more varied "-aspis" fish with true jaws, and the most famous genus by far was the 30-foot-long Dunkleosteus, one of the biggest fish that ever lived.
Perhaps because they were so slow and awkward, placoderms vanished by the end of the Devonian period, outclassed by two other newly evolved families of jawed fish: the chondrichthians (fish with cartilaginous skeletons) and osteichthyans (fish with bony skeletons). The chondrichthians included prehistoric sharks, which went on to tear their own bloody path through evolutionary history. The osteichthyans, meanwhile, split into two further groups: the actinopterygians (ray-finned fish) and sarcopterygians (lobe-finned fish).
Ray-finned fish, lobe-finned fish, who cares? Well, you do: the lobe-finned fishes of the Devonian period, such as Panderichthys and Eusthenopteron, had a characteristic fin structure that enabled them to evolve into the first tetrapods–the proverbial "fish out of water" ancestral to all land-living vertebrates, including humans. The ray-finned fish stayed in the water, but went on to become the most successful vertebrates of all: today, there are tens of thousand of species of ray-finned fish, making them the most diverse and numerous vertebrates on the planet (among the earliest ray-finned fish were Saurichthys and Cheirolepis).
The Giant Fish of the Mesozoic Era
No history of fish would be complete without mentioning the giant "dino-fish" of the Triassic, Jurassic and Cretaceous periods (though these fish weren't as numerous as their oversized dinosaur cousins). The most famous of these giants were the Jurassic Leedsichthys, which some reconstructions put at a whopping 70 feet long, and the Cretaceous Xiphactinus, which was "only" about 20 feet long but at least had a more robust diet (other fish, compared to Leedsichthys' diet of plankton and krill). A new addition is Bonnerichthys, yet another large, Cretaceous fish with a tiny, protozoan diet.
Bear in mind, though, that for every "dino-fish" like Leedsichthys there are a dozen smaller prehistoric fish of equal interest to paleontologists. The list is nearly endless, but examples include Dipterus (an ancient lungfish), Enchodus (also known as the "saber-toothed herring"), the prehistoric rabbitfish Ischyodus, and the small but prolific Knightia, which has yielded so many fossils that you can buy your own for less than a hundred bucks.
The Evolution and Behavior of Tyrannosaur Dinosaurs
Just say the word "tyrannosaur," and most people immediately picture the king of all dinosaurs, Tyrannosaurus Rex. However, as any paleontologist worth his pickaxe will tell you, T. Rex was far from the only tyrannosaur roaming the forests, plains, and swamplands of the Cretaceous period (although it was certainly one of the biggest). From the perspective of a small, quivering herbivorous dinosaur, Daspletosaurus, Alioramus, and a dozen or so other tyrannosaur genera were every bit as dangerous, and their teeth were just as sharp.
As with other broad classifications of dinosaurs, the definition of a tyrannosaur (Greek for "tyrant lizard") involves a combination of arcane anatomical features and broad swathes of physiology. Generally speaking, though, tyrannosaurs are best described as large, bipedal, meat- eating theropod dinosaurs possessing powerful legs and torsos; large, heavy heads studded with numerous sharp teeth; and tiny, almost vestigial-looking arms. As a general rule, tyrannosaurs tended to resemble one another more closely than did the members of other dinosaur families (such as ceratopsians), but there are some exceptions, as noted below. (By the way, tyrannosaurs weren't the only theropod dinosaurs of the Cretaceous period; other members of this populous breed included raptors, ornithomimids and feathered "dino-birds.")
The First Tyrannosaurs
As you might already have guessed, tyrannosaurs were closely related to dromaeosaurs–the relatively small, two-legged, vicious dinosaurs better known as raptors.
In this light, it's not surprising that one of the oldest tyrannosaurs yet discovered–Guanlong, which lived in Asia about 160 million years ago–was about the size of your average raptor, about 10 feet long from head to tail. Other early tyrannosaurs, like Eotyrannus and Dilong (which both lived in the early Cretaceous), were also fairly petite, if no less vicious. (The middle to late Jurassic period witnessed other small, tyrannosaur-like dinosaurs, including Kileskus and Aviatyrannis.)
There's one other fact about Dilong that may permanently change your image of those supposedly mighty tyrannosaurs. Based on analysis of its fossil remains, paleontologists believe this small, Asian dinosaur of the early Cretaceous period (about 130 million years ago) sported a coat of primitive, hair-like feathers. This discovery has led some experts to speculate that all juvenile tyrannosaurs, even the mighty Tyrannosaurus Rex, may have had early feather coats, which they shed on reaching adulthood. (Recently, the discovery in China's Liaoning fossil beds of the large, feathered Yutyrannus has lent weight to the feathered tyrannosaur hypothesis.)
Their initial similarities notwithstanding, tyrannosaurs and raptors quickly diverged along separate evolutionary paths. Most notably, the tyrannosaurs of the late Cretaceous period attained enormous sizes: a full-grown Tyrannosaurus Rex measured about 40 feet long and weighed 7 or 8 tons, while the biggest raptor, the middle Cretaceous Utahraptor, punched in at 2,000 pounds, max. Raptors were also far more agile, slashing at prey with their arms and legs, while the main weapons used by tyrannosaurs were their numerous, sharp teeth and crushing jaws.
Tyrannosaur Lifestyles
Tyrannosaurs truly came into their own during the late Cretaceous period (90 to 65 million years ago), when they prowled modern-day North America and Eurasia. Thanks to numerous (and often surprisingly complete) fossil remains, we know a lot about how tyrannosaurs looked, but not as much about their day-to-day behavior. For example, there's still intense debate about whether Tyrannosaurus Rex actively hunted for its food, scavenged already-dead remains, or both, or whether the average plus-sized tyrannosaur could run faster than a relatively poky 10 miles per hour, about the speed of a kid on a bicycle.
From our modern perspective, perhaps the most puzzling feature of tyrannosaurs is their tiny arms (especially compared to the long arms and flexible hands of their raptor cousins). Today, most paleontologists think the function of these stunted limbs was to lever their owner to an upright position when it was lying on the ground, but it's also possible that tyrannosaurs used their short arms to clutch prey tightly to their chests, or even to get a good grip on females during mating! (By the way, tyrannosaurs weren't the only dinosaurs possessing comically short arms; the arms of Carnotaurus, a non-tyrannosaur theropod, were even shorter.)
How Many Tyrannosaurs?
Because later tyrannosaurs like Tyrannosaurus Rex, Albertosaurus and Gorgosaurus closely resembled one another, there's some disagreement among paleontologists about whether certain tyrannosaurs really merit their own genus (a "genus" is the next step up above an individual species; for example, the genus known as Stegosaurus comprises a handful of closely related species). This situation isn't improved by the occasional discovery of (very) incomplete tyrannosaur remains, which can make assigning a likely genus an impossible bit of detective work.
To take one case, the genus known as Gorgosaurus isn't accepted by everyone in the dinosaur community, some experts believing this was really an individual species of Albertosaurus. And in a similar vein, some paleontologists think the dinosaur known as Nanotyrannus ("tiny tyrant") may actually have been a juvenile Tyrannosaurus Rex, the offspring of a closely related genus, or perhaps a new kind of raptor and not a tyrannosaur at all!
Million Years of Shark Evolution
If you went back in time and looked at the first, unremarkable prehistoric sharks of the Ordovician period–about 420 million years ago–you might never guess that their descendants would become such dominant creatures, holding their own against vicious aquatic reptiles like pliosaurs and mosasaurs and going on to become the "apex predators" of the world's oceans. Today, few creatures in the world inspire as much fear as the Great White Shark, the closest nature has come to a pure killing machine.
Before discussing shark evolution, though, it's important to define what we mean by "shark." Technically, sharks are a suborder of fish whose skeletons are made out of cartilage rather than bone; sharks are also distinguished by their streamlined, hydrodynamic shapes, sharp teeth, and sandpaper-like skin. Frustratingly for paleontologists, skeletons made of cartilage don't persist in the fossil record nearly as well as skeletons made of bone–which is why so many prehistoric sharks are known primarily (if not exclusively) by their fossilized teeth.
The First Sharks
We don't have much in the way of direct evidence, except for a handful of fossilized scales, but the first sharks are believed to have evolved during the Ordovician period, about 420 million years ago (to put this into perspective, the first tetrapods didn't crawl up out of the sea until 400 million years ago). The most important genus that has left significant fossil evidence is the difficult-to-pronounce Cladoselache, numerous specimens of which have been found in the American midwest.
As you might expect in such an early shark, Cladoselache was fairly small, and it had some odd, non-shark-like characteristics–such as a paucity of scales (except for small areas around its mouth and eyes) and a complete lack of "claspers," the sexual organ by which male sharks attach themselves (and transfer sperm to) the females.
After Cladoselache, the most important prehistoric sharks of ancient times were Stethacanthus, Orthacanthus and Xenacanthus. Stethacanthus measured only six feet from snout to tail but already boasted the full panoply of shark features–scales, sharp teeth, distinctive fin structure, and a sleek, hydrodynamic build. What set this genus apart were the bizarre, ironing-board-like structures atop the backs of males, which were probably somehow used during mating. The comparably ancient Stethacanthus and Orthacanthus were both fresh-water sharks, distinguished by their small size, eel-like bodies, and odd spikes protruding from the tops of their heads (which may have delivered jabs of poison to bothersome predators).
The Sharks of the Mesozoic Era
Considering how common they were during the preceding geologic periods, sharks kept a relatively low profile during most of the Mesozoic Era, because of intense competition from aquatic reptiles like ichthyosaurs and plesiosaurs. By far the most successful genus was Hybodus, which was built for survival: this prehistoric shark had two types of teeth, sharp ones for eating fish and flat ones for grinding mollusks, as well as a sharp blade jutting out of its dorsal fin to keep other predators at bay. The cartilaginous skeleton of Hybodus was unusually tough and calcified, explaining this shark's persistence both in the fossil record and in the world's oceans, which it prowled from the Triassic to the early Cretaceous periods.
Prehistoric sharks really came into their own during the middle Cretaceous period, about 100 million years ago. Both Cretoxyrhina (about 25 feet long) and Squalicorax (about 15 feet long) would be recognizable as "true" sharks by a modern observer; in fact, there's direct tooth-mark evidence that Squalicorax preyed on dinosaurs that blundered into its habitat. Perhaps the most surprising shark from the Cretaceous period is the recently discovered Ptychodus, a 30-foot-long monster whose numerous, flat teeth were adapted to grinding up tiny mollusks, rather than large fish or aquatic reptiles.
After the Mesozoic – Introducing Megalodon
After the dinosaurs (and their aquatic cousins) went extinct 65 million years ago, prehistoric sharks were free to complete their slow evolution into the remorseless killing machines we know today. Frustratingly, though, the fossil evidence for the sharks of the Miocene epoch (for example) consists almost exclusively of teeth–thousands and thousands of teeth, so many that you can buy yourself one on the open market. The Great White-sized Otodus, for example, is known almost exclusively by its teeth, from which paleontologists have reconstructed this fearsome, 30-foot-long shark.
By far the most famous prehistoric shark of this time period was Megalodon, adult specimens of which measured 70 feet from head to tail and weighed as much as 50 tons. Megalodon was a true apex predator of the worlds' oceans, feasting on everything from whales, dolphins and seals to giant fish and (presumably) equally giant squids. No one knows why this monster went extinct about two million years ago; the most likely candidates include climate change and the resulting disappearance of its usual prey.
Cladoselache Shark
Cladoselache (Greek for "branch-toothed shark"); pronounced CLAY-doe-SELL-ah-kee
Oceans worldwide
Historical Period:
Late Devonian (370 million years ago)
Size and Weight:
About 6 feet long and 25-50 pounds
Marine animals
Distinguishing Characteristics:
Slender build; lack of scales or claspers
About Cladoselache:
Cladoselache is one of those prehistoric sharks that's more famous for what it didn't have than for what it did.
Specifically, this Devonian shark was almost completely devoid of scales, except on specific parts of its body, and it also lacked the "claspers" that the vast majority of sharks (both prehistoric and modern) use to impregnate females. As you may have guessed, paleontologists are still trying to puzzle out exactly how Cladoselache reproduced!
Another odd thing about Cladoselache was its teeth–which weren't sharp and tearing like those of most sharks, but smooth and blunt, an indication that this creature swallowed fish whole after grasping them in its muscular jaws. Unlike most sharks of the Devonian period, Cladoselache has yielded some exceptionally well-preserved fossils (many of them unearthed from a geological deposit near Cleveland), some of which bear imprints of recent meals as well as internal organs.
300 Million Years of Amphibian Evolution
Here's the strange thing about amphibian evolution: You wouldn't know it from the small (and rapidly dwindling) population of frogs, toads and salamanders alive today, but for tens of millions of years spanning the late Carboniferous and early Permian periods amphibians were the dominant land animals on earth. Some of these ancient creatures achieved crocodile-like sizes (up to 15 feet long, which may not seem so big today but was positively huge 300 million years ago) and terrorized smaller animals as the "apex predators" of their swampy ecosystems.
Before going further, it's helpful to define what the word "amphibian" means. Amphibians differ from other vertebrates in three main ways: first, newborn hatchlings live underwater and breathe via gills, which then disappear as the juvenile undergoes a "metamorphosis" into its adult, air-breathing form (juveniles and adults can look very different, as in the case of baby tadpoles and full-grown frogs). Second, adult amphibians lay their eggs in water, which significantly limits their mobility when colonizing land. And third (and less strictly), the skin of modern amphibians tends to be "slimy" rather than reptile-scaly, which allows for the additional transport of oxygen for respiration.
The First Amphibians
As is often the case in evolutionary history, it's impossible to pinpoint the exact moment when the first tetrapods (the four-legged fish that crawled out of the shallow seas 400 million years ago and swallowed gulps of air with primitive lungs) turned into the first true amphibians.
In fact, until recently, it was fashionable to describe these tetrapods as amphibians, until it occurred to experts that most tetrapods didn't share the full spectrum of amphibian characteristics. For example, three important genera of the early Carboniferous period–Eucritta, Crassigyrinus and Greererpeton–can be variously (and fairly) described as either tetrapods or amphibians, depending on which features are being considered.
It's only in the late Carboniferous period, from about 310 to 300 million years ago, that we can comfortably refer to the first true amphibians. By this time, some genera had attained relatively monstrous sizes–a good example being Eogyrinus ("dawn tadpole"), a slender, crocodile-like creature that measured 15 feet from head to tail. (Interestingly, the skin of Eogyrinus was scaly rather than moist, evidence that the earliest amphibians needed to protect themselves from dehydration.) Another late Carboniferous/early Permian genus, Eryops, was much shorter than Eogyrinus but more sturdily built, with massive, tooth-studded jaws and strong legs.
At this point, it's worth noting a rather frustrating fact about amphibian evolution: modern amphibians (which are technically known as "lissamphibians") are only remotely related to these early monsters. Lissamphibians (which include frogs, toads, salamanders, newts and rare, earthworm-like amphibians called "caecilians") are believed to have radiated from a common ancestor that lived in the middle Permian or early Triassic periods, and it's unclear what relationship this common ancestor may have had to late Carboniferous amphibians like Eryops and Eogyrinus. (It's possible that modern lissamphibians branched off from the late Carboniferous Amphibamus, but not everyone subscribes to this theory.)
The Two Types of Prehistoric Amphibians: Lepospondyls and Temnospondyls
As a general (though not very scientific) rule, the amphibians of the Carboniferous and Permian periods can be divided into two camps: small and weird-looking (the lepospondyls), and big and reptile-like (the temnospondyls). The lepospondyls were mostly aquatic or semi-aquatic, and more likely to have the slimy skin characteristic of modern amphibians. Some of these creatures (such as Ophiderpeton and Phlegethontia) resembled small snakes; others (like Microbrachis) were reminiscent of salamanders; and some were simply unclassifiable. A good example of the last is Diplocaulus: this three-foot-long lepospondyl had a huge, boomerang-shaped skull, which might have functioned as an undersea rudder.
Dinosaur enthusiasts should find the temnospondyls easier to swallow. These amphibians anticipated the classic reptilian body plan of the Mesozoic Era (long trunks, stubby legs, big heads, and in some cases scaly skin), and many of them (like Metoposaurus and Prionosuchus) resembled large crocodiles. Probably the most infamous of the temnospondyl amphibians was the impressively named Mastodonsaurus (the name means "nipple-toothed lizard" and has nothing to do with the elephant ancestor), which had an almost comically oversized head that accounted for nearly a third of its 20-foot-long body.
For a good portion of the Permian period, the temnospondyl amphibians were the top predators of the earth's land masses. That all changed with the evolution of the therapsids ("mammal-like reptiles") toward the end of the Permian period; these large, nimble carnivores chased the temnospondyls back into the swamps, where most of them slowly died out by the beginning of the Triassic period. There were a few scattered survivors, though: for example, the 15-foot-long Koolasuchus thrived in Australia in the middle Cretaceous period, about a hundred million years after its temnospondyl cousins of the northern hemisphere had gone extinct.
Introducing Frogs and Salamanders
As stated above, modern amphibians (known as "lissamphibians") branched off from a common ancestor that lived anywhere from the middle Permian to the early Triassic periods. Since the evolution of this group is a matter of continuing study and debate, the best we can do is identify the "earliest" true frogs and salamanders, with the caveat that future fossil discoveries may push the clock back even further. (Some experts claim that the late Permian Gerobatrachus, also known as the Frogamander, was ancestral to these two groups, but the verdict is mixed.)
As far as prehistoric frogs are concerned, the best current candidate is Triadobatrachus ("triple frog"), which lived about 250 million years ago, during the early Triassic period. Triadobatrachus differed from modern frogs in some important ways (for example, it had a tail, the better to accommodate its unusually large number of vertebrae, and it could only flail its hind legs rather than use them to execute long-distance jumps), but its resemblance to modern frogs is unmistakable. The earliest known true frog was the tiny Vieraella of South America, while the first true salamander is believed to have been Karaurus, a tiny, slimy, big-headed amphibian that lived in late Jurassic central Asia.
Ironically–considering that they evolved over 300 million years ago and have survived, with various waxings and wanings, into modern times–amphibians are among the most threatened creatures on the earth today. Over the last few decades, a startling number of frog, toad and salamander species spiraled toward extinction, though no one knows exactly why: the culprits may include pollution, global warming, deforestation, disease, or a combination of these and other factors. If current trends persist, amphibians may be the first major classification of vertebrates to disappear off the face of the earth!
Biological Evolution
What Is Evolution?
Biological evolution is defined as any genetic change in a population that is inherited over several generations. These changes may be small or large, noticeable or not so noticeable.
In order for an event to be considered an instance of evolution, changes have to occur on the genetic level of a population and be passed on from one generation to the next.
This means that the genes, or more specifically, the alleles in the population change and are passed on.
These changes are noticed in the phenotypes (expressed physical traits that can be seen) of the population.
A change on the genetic level of a population is defined as a small-scale change and is called microevolution.
Biological evolution also includes the idea that all of life is connected and can be traced back to one common ancestor. This is called macroevolution.
What Evolution Is Not
Biological evolution is not defined as simply change over time.
Many organisms experience changes over time, such as weight loss or gain. These changes are not considered instances of evolution because they are not genetic changes that can be passed on to the next generation.
Is Evolution a Theory?
Evolution is a scientific theory that was proposed by Charles Darwin. A scientific theory gives explanations and predictions for naturally occurring phenomena based on observations and experimentations. This type of theory attempts to explain how events seen in the natural world work.
The definition of a scientific theory differs from the common meaning of theory, which is defined as a guess or a supposition about a particular process.
In contrast, a good scientific theory must be testable, falsifiable, and substantiated by factual evidence.
When it comes to a scientific theory, there is no absolute proof. It's more a case of confirming the reasonability of accepting a theory as a viable explanation for a particular event.
What Is Natural Selection?
Natural selection is the process by which biological evolutionary changes take place. Natural selection acts on populations and not individuals. It is based on the following concepts:
- Individuals in a population have different traits which can be inherited.
- These individuals produce more young than the environment can support.
- The individuals in a population that are best suited to their environment will leave more offspring, resulting in a change in the genetic makeup of a population.
The genetic variations that arise in a population happen by chance, but the process of natural selection does not. Natural selection is the result of the interactions between genetic variations in a population and the environment.
The environment determines which variations are more favorable. Individuals that possess traits that are better suited to their environment will survive to produce more offspring than other individuals. More favorable traits are thereby passed on to the population as a whole.
How Does Genetic Variation Occur in a Population?
Genetic variation occurs mainly through DNA mutation, gene flow (movement of genes from one population to another) and sexual reproduction. Due to the fact that environments are unstable, populations that are genetically variable will be able to adapt to changing situations better than those that do not contain genetic variations.
Sexual reproduction allows for genetic variations to occur through genetic recombination. Recombination occurs during meiosis and provides a way for producing new combinations of alleles on a single chromosome. Independent assortment during meiosis allows for an indefinite number of combinations of genes.
Sexual reproduction makes it possible to assemble favorable gene combinations in a population or to remove unfavorable gene combinations from a population. Populations with more favorable genetic combinations will survive in their environment and reproduce more offspring than those with less favorable genetic combinations.
Biological Evolution Versus Creation
The theory of evolution has caused controversy from the time of its introduction until today. The controversy stems from the perception that biological evolution is at odds with religion concerning the need for a divine creator. Evolutionists contend that evolution does not address the issue of whether or not God exists, but attempts to explain how natural processes work.
In doing so however, there is no escaping the fact that evolution contradicts certain aspects of some religious beliefs. For example, the evolutionary account for the existence of life and the biblical account of creation are quite different.
Evolution suggests that all life is connected and can be traced back to one common ancestor. A literal interpretation of biblical creation suggests that life was created by an all powerful, supernatural being (God).
Still others have tried to merge these two concepts by contending that evolution does not exclude the possibility of the existence of God, but merely explains the process by which God created life. This view however, still contradicts a literal interpretation of creation as presented in the bible.
In paring down the issue, a major bone of contention between the two views is the concept of macroevolution. For the most part, evolutionists and creationists agree that microevolution does occur and is visible in nature.
Macroevolution however, refers to the process of evolution that takes place on the level of species, in which one species evolves from another species. This is in stark contrast to the biblical view that God was personally involved in the formation and creation of living organisms.
For now, the evolution/creation debate continues on and it appears that the differences between these two views are not likely to be settled any time soon.
8 Incredible Facts About Human Evolution
Homo sapiens evolved about 200-150,000 years ago in Africa, but our story as a species stretches back much further than that with early human ancestors. And the evolution of Homo sapiens is itself a tangled tale, full of unanswered questions and gothic family melodrama. Here are a few facts you may not know about the human evolutionary story.
1. Early human beings left Africa over 1 million years ago
Most of us have heard the story about how Homo sapiens poured out of Africa into Europe and Asia starting about 80,000 years ago. What you may not realize is that our ancestor, Homo erectus, had been taking the same routes out of Africa on and off for over 1 million years. In fact, when Homo sapiens left Africa, they would have encountered other humans who looked very much like themselves – these would be the descendents of the common ancestor we share with Neanderthals, as well as the descendents of Homo erectus. All of these people were early humans. And they had been wandering around Eurasia for hundreds of thousands of years.
2. Humans have incredibly low genetic diversity
Humans are among the least genetically diverse apes, mostly because we all appear to be descended from a small group of humans who lived in East Africa. To describe genetic diversity, population geneticists use a measure called "effective population size." Put extremely simply, effective population size is how many people you would need to reproduce the genetic diversity of our full population. For humans, this number hovers around 15,000 individuals, which is pretty insane when you consider our actual population size is 7 billion. As a point of comparison, some species of mice have an effective population size of 733,000.
3. You may be part Neanderthal
This is pretty widely known, but it bears repeating. Recent genetic analysis of Neanderthal bones reveals that there are some Neanderthal genes that have made their way into modern non-African populations. This suggests that when Cro-Magnons entered Europe, the Middle East and Asia, they probably had children with the local Neanderthal populations. We are all one happy human family.
4. The human population crashed about 80,000 years ago
Something mysterious happened about 80,000 years ago that reduced humanity's effective population size. If you recall, the effective population size is not the same thing as the actual population size – it's a measure of genetic diversity. So basically, our genetic diversity shrank by a lot 80,000 years ago. There are a lot of theories about why this might be, ranging from an apocalyptic disaster caused by the eruption of the Toba volcano, to something more mundane like interbreeding among small populations.
5. Humans navigated the Indian ocean in boats 50,000 years ago
Homo sapiens arrived in Australia roughly 50,000 years ago. How the hell did they get there from the shores of Africa? They used small boats, probably lashed together out of reeds. (Likely they were similar to the boats that brought us from Asia to the Americas over 17,000 years ago.) It was the Paleolithic equivalent of flying to the moon in a tin can. It shouldn't have worked, but it did. Using those small boats, we crossed the Pacific many times and populated an entire continent.
6. Homo sapiens has only had a culture for less than 50,000 years
While we're talking about all the cool things that happened 50,000 years ago, it's worth noting that many anthropologists now believe early humans probably did not develop what we would recognize as culture until around that time. This is amazing when you consider that the "mitochondrial Eve" theory suggests that we are all descended from one East African woman who lived about 200-150,000 years ago. Given that Homo sapiens evolved around the time of mitochondrial Eve, that means our species hung around for a really long time before we developed awesome things like art, symbolic communication, ornaments, and fancy bone tools. Certainly, pre-cultural humans had fairly sophisticated toolkits and fire, but we have very little evidence that they had art and symbolic communication, which are the cornerstones of that thing we call "culture." Some anthropologists believe that we didn't even invent language until that cultural explosion, but this is almost impossible to prove one way or the other.
7. Homo sapiens has always used fire as a tool
Homo sapiens evolved after our ancestors tamed fire and started making tools. This sounds simple, but when you start to think about it, the implications are profound. As a species, we have never existed without one of the most important tools for building a civilization: tamed fire. As a species, we are born tool users and fire makers. Some might even say that means we were born cyborgs, because our species has always been augmented by the invention of artificially made fire and tools. Whoa.
8. Homo sapiens is still evolving rapidly
Good news, everyone! Homo sapiens is still evolving – and one day our progeny will be as different from us as we are from Homo erectus. Evolutionary biologists have isolated a few areas of the human genome that are under rapid selection. That means mutations in those genes are spreading rapidly throughout the population. Many of these mutations are related to brain size and development, and others have to do with our ability to tolerate certain kinds of foods (like dairy) and disease resistance. This has led some biologists to wonder whether we are evolving to be more intelligent, but it is not yet clear whether the evolutionary changes we are seeing have anything to do with intelligence — especially since our brains are actually shrinking. Still, it's good to know that that the genes which control one of my favorite anatomical systems is still evolving.
Funny and Interesting Medical Fact
Medical facts can be fun. From things we thought we knew were true to things that just seem completely unbelievable, these amazing medical facts will have you in disbelief. But they are all true.
- Your tongue has a unique print similar to your fingerprints.
- Your brain is more active at night than during the day.
- If you squeezed out all of the bacteria from your intestines, you could almost fill up a coffee mug.
- Undertakers report that human bodies do not deteriorate as quickly as they used to. The reason, they believe, is that the modern diet contains so many preservatives that these chemicals tend to prevent the body from decomposition too rapidly after death.
- Facial hair grows faster than any other hair on the human body, which explains the 5 o clock shadow that men get.
- The storage capacity of human brain exceeds 4 Terabytes.
- The acid in your stomach, that which helps digest your food, is strong enough to dissolve razor blades! Don't try swallowing metal objects to prove this, but hydrochloric acid (found in the stomach) can dissolve a variety of metals.
- Women's hearts beat faster than men's due to having a smaller area to pump blood to.
- Your stomach lining replaces itself every three to four days. If it did not do this your stomach would digest itself. If you have ever had a stomach ulcer you will know how painful this is.
- A scientist discovered this weird medical fact – the left lung is smaller than the right lung to make room for the heart.
- During your lifetime you will produce enough saliva to full up two swimming pools.
- Every time you sneeze it reaches speeds of over 100mph, which is why people struggle to keep their eyes open when they sneeze.
- This random medical fact is one for the ladies – women have a better sense of smell than men and continue to have a better sense of smell throughout their lives.
- Everyone has a unique smell, except for identical twins.
- The attachment of the human skin to muscles is what causes dimples.
- In 1972, a group of scientists reported that you could cure the common cold by freezing the big toe.
- The number one cause of blindness in the United States is diabetes.
- People who laugh a lot are much healthier than those who don't. Dr. Lee Berk at the Loma Linda School of Public Health in California found that laughing lowers levels of stress hormones, and strengthens the immune system. Six-year-olds have it best – they laugh an average of 300 times a day. Adults only laugh 15 to 100 times a day.
- In 1815 French chemist Michael Eugene Chevreul realized the first link between diabetes and sugar metabolism when he discovered that the urine of a diabetic was identical to grape sugar.
- The first Band-Aid Brand Adhesive Bandages were three inches wide and eighteen inches long. You made your own bandage by cutting off as much as you needed.
- According to the Centers for Disease Control and Prevention (CDC), 18 million courses of antibiotics are prescribed for the common cold in the United States per year. Research shows that colds are caused by viruses. 50 million unnecessary antibiotics are prescribed for viral respiratory infections.
- It takes an interaction of 72 different muscles to produce human speech.
- The first known heart medicine was discovered in an English garden. In 1799, physician John Ferriar noted the effect of dried leaves of the common plant, digitalis purpurea, on heart action. Still used in heart medications, digitalis slows the pulse and increases the force of heart contractions and the amount of blood pumped per heartbeat.
- Coca-Cola contained Coca (whose active ingredient is cocaine) from 1885 to 1903.
- Ketchup was sold in the 1830s as medicine.
How Is a Stroke Treated?
Treatment for a stroke depends on whether it is ischemic or hemorrhagic. Treatment for a transient ischemic attack (TIA) depends on its cause, how much time has passed since symptoms began, and whether you have other medical conditions.
Strokes and TIAs are medical emergencies. If you have stroke symptoms, call 9–1–1 right away. Do not drive to the hospital or let someone else drive you. Call an ambulance so that medical personnel can begin life-saving treatment on the way to the emergency room. During a stroke, every minute counts.
Once you receive initial treatment, your doctor will try to treat your stroke risk factors and prevent complications.
Treating Ischemic Stroke and Transient Ischemic Attack
An ischemic stroke or TIA occurs if an artery that supplies oxygen-rich blood to the brain becomes blocked. Often, blood clots cause the blockages that lead to ischemic strokes and TIAs.
Treatment for an ischemic stroke or TIA may include medicines and medical procedures.
A medicine called tissue plasminogen activator (tPA) can break up blood clots in the arteries of the brain. A doctor will inject tPA into a vein in your arm. This medicine must be given within 4 hours of the start of symptoms to work. Ideally, it should be given as soon as possible.
If, for medical reasons, your doctor can't give you tPA, you may get an antiplatelet medicine. For example, aspirin may be given within 48 hours of a stroke. Antiplatelet medicines help stop platelets from clumping together to form blood clots.
Your doctor also may prescribe anticoagulants, or "blood thinners." These medicines can keep blood clots from getting larger and prevent new blood clots from forming.
Medical Procedures
If you have carotid artery disease, your doctor may recommend a carotid endarterectomy (END-ar-ter-EK-to-me) or carotid artery percutaneous (per-ku-TA-ne-us) coronary intervention, sometimes referred to as angioplasty (AN-jee-oh-plas-tee). Both procedures open blocked carotid arteries.
Researchers are testing other treatments for ischemic stroke, such as intra-arterial thrombolysis (throm-BOL-ih-sis) and mechanical clot (embolus) removal in cerebral ischemia (MERCI).
In intra-arterial thrombolysis, a long flexible tube called a catheter is put into your groin (upper thigh) and threaded to the tiny arteries of the brain. Your doctor can deliver medicine through this catheter to break up a blood clot in the brain.
MERCI is a device that can remove blood clots from an artery. During the procedure, a catheter is threaded through a carotid artery to the affected artery in the brain. The device is then used to pull the blood clot out through the catheter.
Treating Hemorrhagic Stroke
A hemorrhagic stroke occurs if an artery in the brain leaks blood or ruptures (breaks open). The first steps in treating a hemorrhagic stroke are to find the cause of bleeding in the brain and then control it.
Unlike ischemic strokes, hemorrhagic strokes aren't treated with antiplatelet medicines and blood thinners. This is because these medicines can make bleeding worse.
If you're taking antiplatelet medicines or blood thinners and have a hemorrhagic stroke, you'll be taken off the medicine.
If high blood pressure is the cause of bleeding in the brain, your doctor may prescribe medicines to lower your blood pressure. This can help prevent further bleeding.
Surgery also may be needed to treat a hemorrhagic stroke. The types of surgery used include aneurysm clipping, coil embolization (EM-bol-ih-ZA-shun), and arteriovenous malformation (AVM) repair.
Aneurysm Clipping and Coil Embolization
If an aneurysm (a balloon-like bulge in an artery) is the cause of a stroke, your doctor may recommend aneurysm clipping or coil embolization.
Aneurysm clipping is done to block off the aneurysm from the blood vessels in the brain. This surgery helps prevent further leaking of blood from the aneurysm. It also can help prevent the aneurysm from bursting again.
During the procedure, a surgeon will make an incision (cut) in the brain and place a tiny clamp at the base of the aneurysm. You'll be given medicine to make you sleep during the surgery. After the surgery, you'll need to stay in the hospital's intensive care unit for a few days.
Coil embolization is a less complex procedure for treating an aneurysm. The surgeon will insert a tube called a catheter into an artery in the groin. He or she will thread the tube to the site of the aneurysm.
Then, a tiny coil will be pushed through the tube and into the aneurysm. The coil will cause a blood clot to form, which will block blood flow through the aneurysm and prevent it from bursting again.
Coil embolization is done in a hospital. You'll be given medicine to make you sleep during the surgery.
Arteriovenous Malformation Repair
If an AVM is the cause of a stroke, your doctor may recommend an AVM repair. (An AVM is a tangle of faulty arteries and veins that can rupture within the brain.) AVM repair helps prevent further bleeding in the brain.
Doctors use several methods to repair AVMs. These methods include:
- Surgery to remove the AVM
- Injecting a substance into the blood vessels of the AVM to block blood flow
- Using radiation to shrink the blood vessels of the AVM
Treating Stroke Risk Factors
After initial treatment for a stroke or TIA, your doctor will treat your risk factors. He or she may recommend lifestyle changes to help control your risk factors.
Lifestyle changes may include quitting smoking, following a healthy diet, maintaining a healthy weight, and being physically active.
If lifestyle changes aren't enough, you may need medicine to control your risk factors.
Quitting Smoking
If you smoke or use tobacco, quit. Smoking can damage your blood vessels and raise your risk of stroke and other health problems. Talk with your doctor about programs and products that can help you quit. Also, try to avoid secondhand smoke. Secondhand smoke also can damage the blood vessels.
For more information about how to quit smoking, go to the Health Topics Smoking and Your Heart article and the National Heart, Lung, and Blood Institute's (NHLBI's) "Your Guide to a Healthy Heart." Although these resources focus on heart health, they include general information about how to quit smoking.
The U.S. Department of Health and Human Services (HHS) also has information about how to quit smoking.
Following a Healthy Diet
A healthy diet is an important part of a healthy lifestyle. Choose a variety of fruits, vegetables, and grains; half of your grains should come from whole-grain products.
Choose foods that are low in saturated fat, trans fat, and cholesterol. Healthy choices include lean meats, poultry without skin, fish, beans, and fat-free or low-fat milk and milk products.
Choose and prepare foods with little sodium (salt). Too much salt can raise your risk of high blood pressure. Studies show that following the Dietary Approaches to Stop Hypertension (DASH) eating plan can lower blood pressure.
Choose foods and beverages that are low in added sugar. If you drink alcoholic beverages, do so in moderation.
For more information about following a healthy diet, go to the NHLBI's Aim for a Healthy Weight Web site, "Your Guide to a Healthy Heart," and "Your Guide to Lowering Your Blood Pressure With DASH." All of these resources provide general information about healthy eating.
Maintaining a Healthy Weight
Maintaining a healthy weight can lower your risk of stroke. A general goal to aim for is a body mass index (BMI) of less than 25.
BMI measures your weight in relation to your height and gives an estimate of your total body fat. You can measure your BMI using the NHLBI's online calculator, or your health care provider can measure your BMI.
A BMI between 25 and 29.9 is considered overweight. A BMI of 30 or more is considered obese. A BMI of less than 25 is the goal for preventing a stroke.
For more information about losing weight and maintaining your weight, go to the HEALTH TOPICS Overweight and Obesity article.
Being Physically Active
Regular physical activity can help control many stroke risk factors, such as high blood pressure, unhealthy cholesterol levels, and excess weight.
Talk with your doctor before you start a new exercise plan. Ask him or her how much and what kinds of physical activity are safe for you.
People gain health benefits from as little as 60 minutes of moderate-intensity aerobic activity per week. The more active you are, the more you will benefit.
Generic and Trade Names of Drugs for Treatment of Fever
New HIV-Neutralizing Antibody Offers Hope for the Cure of HIV
The research team has now discovered that one particular bNAb may be able to recognize this signature protein, even as it takes on different conformations during infection, making it easier to detect and neutralize the viruses in an infected patient.
First author Louise Scharf said, "The same collaborators at Rockefeller University are already testing bNAbs in a human treatment in a clinical trial. Although the initial trial will not include 8ANC195, the antibody may be included in a combination therapy trial in the near future."
Generic of Drugs for Treatment of Chest Pain
Amyl Nitrite
Nitroglycerin Ointment
Nitroglycerin Skin Patches
Nitroglycerin Tablets, Capsules and Spray
Trimetazidine Hydrochloride
The 10 "T"s to help relieve depression and heartache:
1. Trust yourself and the universe.
Know that the universe has a greater plan for us than we can ever imagine. My first authentic feeling of surrender came by reading self-help books. This gave me the first push toward believing and trusting in the power of the universe. It's the greatest comfort knowing that you are taken care of.
2. Touch other people's lives by sharing your personal story.
By reaching out you can help others in similar situations. Tiny Buddha and other spiritual websites helped me recognize that I am not alone with my emotions. There are people out there fighting the same type of battles who are willing to share their experiences. This kind of support system was needed in order to rebuild a healthy relationship with myself.
3. Therapy sessions are like taking an inner journey.
With my therapist's help, it became clear to me why I acted the way I did and how I could overcome the fear, sorrow, and aggression I felt trapped with. Although professional therapy worked for me on a deeper level, the support from friends and family has been invaluable.
A previous teacher also helped me tremendously during depression. He instantly saw my full potential and became my friend and mentor. We keep in regular contact and he is a true source of inspiration that motivates me to be the person I want to be.
I encourage everyone to connect with someone they trust. Perhaps it's your grandmother, aunt, friend, teacher, or neighbor who inspires you. Whoever it is, cherish that relationship.
4. Treat yourself (and others) with respect and compassion.
When suffering from depression and heartbreak, the last thing you may want to do is take a walk or go for a haircut. Beauty comes from inside, without a doubt, but taking care of yourself will make you feel better and stronger.
Start with little things, like moisturizing your skin with some nice smelling body lotion. You deserve the extra attention.
5. Tear down those walls that you have built up saying that you are not good enough.
I tell myself every day that I am a unique and beautiful, and I believe it.
6. Thank the universe or your higher power for keeping you healthy, safe, and alive.
I do this every night before going to sleep. It truly helps. I promise.
7. Tea and other hot drinks (not coffee) are calming.
Lighting a candle and drinking a nice cup of green tea can be such a soothing sensation.
8. Trying new things is fun.
For me, practicing guided mediations became an important part of my healing. I am still learning and loving every minute I dedicate to myself.
9. Traveling can be therapeutic, relaxing, and stimulating.
Until recently, traveling was my drug, as I would "use" it to escape from my anxiety. It seemed like a great idea for years, even though the outcome was always the same: I'd spend all my money and still feel empty, as the destination and people never made me feel complete in the way I'd hoped they would.
It took me a long time to accept and realize that serenity and peace start from within. Today, traveling is pure joy and inspiration.
10. Taking risks and chances is crucial to find a sense of purpose.
By throwing yourself out there, amazing opportunities can and will arise. I know this because it has happened to me several times.
For example, after reading the book Find Your Happy, by fellow Tiny Buddha contributor Shannon Kaiser, I suddenly felt a wave of courage to write publicly.
Service of Microscopy
Detailed Microscopic Examination
Our analysts have taken on a diverse range of projects requiring microscopic examinations. From determining general particle size distribution of water turbidity to detailed characterization of wooddust samples, we are able to customize a method of analysis for your specific project.
Cryptosporidium & Giardia
ALS Laboratory Group (ALS) offers analysis for the detection of Cryptosporidium (Crypto) and Giardia in water using the recently approved EPA method 1623 immuno-magnetic separation technique. This procedure can isolate both Crypto and Giardia using one 10L water sample resulting in improved sensitivity and the lowest possible detection of oocysts per liter.
ALS is AIHA-LAP, LLC, accredited to perform identification and enumeration of environmental mould samples to genus and species. Our capabilities include analysis of bulk, swabs, tapes and air samples for viable moulds, as well as spore traps for non-viable moulds. Our staff is highly trained for these tests offering assistance with sampling strategies and data interpretation. This expertise, along with our AIHA-LAP, LLC, accreditation, can give you confidence in the analysis you are using in your investigations.
Benthic Invertebrates
Many laboratories offer the chemistry services required for in-depth environmental baseline studies, but ALS also offers the associated benthic and phyto/zooplankton identification services. We employ a large number of biologists capable of handling multiple project requirements and deadlines using CAEAL (ISO 17025) accredited procedures. We have analyzed fresh water benthic samples to various taxonomic levels from coast to coast, and can provide reference libraries with each project.
Blue-green (BG) algae have become an organisms of concern in drinking water sources across Canada. ALS can assist water quality professionals in identifying and monitoring BG or any other algae of concern, as well as microcystin-LR quantities. We are capable of reporting detailed identification, counts and biovolumes to ensure the accurate assessment of Canada's water quality.
Human and Microbes
As with many things in life, humans need more than nature provides, not only to battle hazards in nature but also to battle things we have created ourselves. You're asking, "What are these guys talking about?" Biotechnology! Scientists all over the world are experimenting with viruses, bacteria, and fungi for hundreds of reasons. Why mess around with these little creatures? They are the simplest of all organisms. They can also be the most deadly. That is reason enough to study them.
Microbes to Make Medicine
Scientists are working with microbes and the compounds they create to make new medicines to save our lives. You might be vaccinated for pox or the flu. Scientists have studied those viruses to see how they act. Then they came up with a way to teach your immune system to do battle. If you get sick at all, you will be able to fight off the infection. Labs are also developing drugs that help you fight infections after you get the disease. We already spoke about antibiotics. Labs are creating new and stronger antibiotics every day.
Microbes in War
Although nobody likes to talk about it, humans have a history of using disease and compounds created by microbes in warfare. Labs were built to create chemical compounds that would kill people. They also isolate diseases (viruses) that could be released to infect entire populations of people. Most of the world has chosen not to develop diseases for use in war. They realized how dangerous and uncontrollable these diseases are. Once they are out, they might not be able to be stopped.
Cleaning the Environment
Let's finish on a good note. Scientists are also working with microbes to help the environment. In reality, the environment did not need help; we're just trying to lower the negative impact we have on the environment. Good examples are the bacteria that have developed to break down oil in the water. If a tanker leaked and oil began to get into the water, these bacteria could be released to break down the oil. The resulting compounds would not hurt the environment. Scientists are also working with bacteria and fungi to help breakdown garbage.
Facts about Confocal Laser Scanning Microscopy
In CLSM, a laser light beam is focused to a diffraction-limited spot in the focal plane. Images are captured by scanning the beam over the focal plane, and recording the variations in fluorescence intensity.
A pinhole aperture in front of the fluorescence detectors, placed to correspond with the focal plane (hence confocal), excludes most of the out-of-focus fluorescence. By recording fluorescence from mainly the focal plane, you acquire an image that is an "optical section" of the specimen.
By scanning consecutive focal planes, a series of optical sections can be acquired. These optical sections can be assembled in a "z-stack", which can be used for 3D-analysis and 3D-rendering of the fluorescent structures.
What's so good with confocal microscopy?
The immediate gain in confocal microscopy, when compared with conventional epifluorescence microscopy, is the superior depth resolution. With a high-resolution objective (numerical aperture 1,3-1,4) it is possible to acquire an image in which most of the signal comes from a ca. 0,5 µm tick optical section! With the epifluorescence microscope (using the same objective) the image would contain light from the entire thickness of the specimen. Thus, the confocal microscope improves the signal-to-noise ratio (S/N) tremendously, making it easier to distinguish small structures in the specimen.
Please note, though, that resolution in the image plane (x/y) is only about 25% better than in conventional light microscopy. The improvement depends on that coherent laser light can be focussed into a smaller spot than non-coherent light from e.g. a Hg-lamp – in all other respects is it "the same microscope optics". However, the combination of a dramatic improvement of S/N due to the optical sectioning, and a marginal improvement in lateral resolution, gives a superior detection of e.g. co-localized fluorescent markers.
And which are the limitations?
It is of course not possible to acquire high-resolution images of deep structures at any depth in a specimen. First, the objective's working distance (distance between lens surface and focal point) is a physical constraint. In practice, however, it is more usual that factors like optical density and variations in the refractive index set an absolute limit at depths around 200 µm in biological specimens. If you need to study deeper volumes you should consider using multiphoton microscopy, which may work down to approximately 500 µm.
Confocal laser scanning microscopy is a good tool for studying different types of dynamic processes. However, the scan speed of the laser beam limits how fast process you can study. For studies of biological processes at the cellular level (and some biochemical processes) it may often suffice to "zoom in" and scan only a small area/volume, thus achieving an adquate frame rate. If this approach is not fast enough, you should consider using conventional (wide-field) fluorescence, TIRF, or spinning disk confocal microscopy, where temporal resolution is limited by the read-out reate of the CCD camera.
Finally: as mentioned above, the resolution (x/y) in a confocal microscope is only marginally better than in conventional light microscopy. If you need to resolve, visualize and exactly locate smaller structures using fluorescent markers, you'll have to use one of many so-called super-resolution (or subdiffraction) microscopy methods, like STED, GSD, GSDIM, PALM, STORM, etc. Please note, though, that these methods are very specialized, have great limitations, and demand special (often not commercially available) technically advanced equipment. Another alternative is to use quantum dots that may first be visualized with fluorescence, and then exactly localized with electron microscopy!
Six Facts About Microscopy
- The magnification of a light microscope is found by multiplying the separate magnifications of its objective and eyepiece lenses.
- The maximum useful magnification of a microscope depends on its resolving power.
- The resolution of a microscope is its ability to distinguish two close structures as separate objects.
- An electron microscope has a higher resolution than a light microscope and so it can be used at a higher magnification.
- The resolution of an electron microscope is due to the shorter wavelength of its electron beam compared to light.
- Staining allows cell structures to be distinguished.
Bacteria Basics
Bacteria are the simplest of creatures that are considered alive. Bacteria are everywhere. They are in the bread you eat, the soil that plants grow in, and even inside of you. They are very simple cells that fall under the heading prokaryotic. That word means they do not have an organized nucleus. Bacteria are small single cells whose whole purpose in life is to replicate.
Okay. So we've told you they don't have an organized nucleus. True. They do have DNA. It is grouped in an area called the nucleoid. They have cell membranes like other cells and even a protective cell wall. Mind you, their cell wall is not like the one in a plant. It's a special kind that bacteria have for protection. They don't have any organelles, just ribosomes. (These are all characteristics of prokaryotes if you remember.)
What Do Bacteria Look Like?
Very small. Very, very small. You might have seen pictures of some bacteria. Since we don't know what you have seen, we'll tell you there are three basic shapes. Spherical bacteria are in the shape of little spheres or balls. They usually form chains of cells like a row of circles. Rod shaped bacteria are look like the E. coli living in your intestine. You can imagine a bunch of bacteria that look like hot dogs. They can make chains like a set of linked sausages. Spiral shaped bacteria twist a little. Think about balloon animals for these shapes. It's like a balloon animal in the shape of a corkscrew.
What Do Bacteria Do?
All sorts of things. Sorry to be so vague, but they do just about everything. Some help plants absorb nitrogen (N) from the soil. Some cause diseases like botulism. Some bacteria even live inside the stomachs of cows to help them break down cellulose. Cows on their own can digest grass and plants about as well as we do. They don't get many nutrients out of the plants and can't break down the cellulose. With those super bacteria, the cellulose can be broken down into sugars and then release all of the energy they need. Imagine if scientists could develop bacteria to live inside of us that would break down plants. That would be something. We could eat grass and leaves all day long.
Good and Bad Microbes
Good Microbes
With such a variety of microscopic organisms, it's bound to happen that there are some that help the world. There will also be some that hurt the world. We will cover those in another section. We're going to cover a few of the good ones here.
Fixing Nitrogen in Soil
There are bacteria that go through a process called fixing nitrogen. These bacteria, living in the roots of plants, actually help them absorb nitrogen from the surrounding soil. The nitrogen is very important for the growth of the plant, and these little bacteria give them an advantage for survival.
Helping Cows Eat Grass
As we said, not all protists are bad for the world. In the bacteria section we already told you about a species that lives in the digestive system in cows. These bacteria help cows break down the cellulose in plants. Similar bacteria live in all sorts of grazing animals, helping them survive off plant material. Many ecosystems are based on creatures that are called herbivores.
Scientists have even discovered fungi that will help you battle bacterial diseases. So you get sick, the doctor looks at you and says you have a bacterial infection, maybe bronchitis. He prescribes an antibiotic to help you get better. Antibiotics are drugs designed to destroy bacteria by weakening their cell walls. When the bacterial cell walls are weak, your immune cells can go in and destroy the bacteria. Although there are many types now, one of the first antibiotics was called penicillin. It was developed from a fungus (a fungus named Penicillium found on an orange, to be exact).
Bad Microbes
With such a variety of microscopic organisms, it's bound to happen that some do not help anything in the world. Some also help the world. We cover those in another section. We're going to cover a few of the bad ones here.
Many species of bacteria cause disease in humans, animals, and even plants. Humans worry about bacteria that cause botulism (bacteria living in spaces without oxygen, such as cans), tetanus and E. coli. You should know that there are also some good forms of E. Coli living in your intestines. They help break down food and live a simple life (and yes, they make it smell down there). There are also E. Coli that can be passed to you from undercooked meat. These bad bacteria can make you very sick and even kill you.
A Role in Natural Selection
We don't know of any viruses that are good for the world. They are an important piece of evolution and natural selection. Weaker and older animals are more easily infected. Those organisms are removed from the population so that healthier animals can survive. But the virus life cycle, that of a parasite, only hurts the organisms. Some even destroy cells in order to reproduce. And don't think you are the only one to get sick. Viruses attack plants and even bacteria. No organism is safe from damage. Examples of viruses include Rabies, Pneumonia, and Meningitis.
Prokaryotes – Missing a Nucleus
If you're looking to learn about cells with a nucleus, this is the wrong place. Prokaryotes do not have an organized nucleus. Their DNA is kind of floating around the cell. It's clumped up, but not inside of a nucleus. If you want to learn about cells with a nucleus, look for information on eukaryotes. And, once again, a prokaryote is a single cell or organisms that does NOT have organized nuclei.
Can You Exist Without a Nucleus?
You can't, but they can. What can you do without a nucleus? You can do a whole lot. Most prokaryotes are bacteria and bacteria can do amazing things. Although they are very simple organisms, they are found everywhere on the planet. Some scientists even think that they may be found on other planets (maybe even Mars). Some places you can find bacteria every day are in your intestines, a cup of natural yogurt, or a bakery. Prokaryotes are the simplest of simple organisms. Here's the checklist.
(1) Prokaryotes have no organized nucleus. Like we said, the DNA is clumped in an area but there is no organized nucleus with a membrane.
(2) Prokaryotes do not usually have any organelles. They will probably have ribosomes inside of their cells, but ribosomes are not technically considered organelles. No chloroplasts. No mitochondria. No nucleus. Not much at all.
(3) Prokaryotes are very small. Because they don't have all of the normal cell machinery, they are limited in size. As always in biology, there are exceptions, but generally, prokaryotes are very small (compared to other cells). Mind you, compared to a virus they are big, but next to an amoeba, tiny.
(4) Prokaryotes don't have mitosis or meiosis like other cells. Scientists don't really have a good way of describing how they duplicate, but it's not through normal means. Check out the bacteria tutorial to get an idea.
The Littlest Organisms
Let's study the wee ones of the world known as the microbes or the microorganisms. If you spend your life studying them, you would be a microbiologist. These are the smallest of the small and the simplest of the simple. Some of them, like viruses, may not even be alive as we currently define life.
What is a Microbe?
What makes a microbe? We suppose you need a microscope to see them. That's about it. There is a huge variety of creatures in this section. They can work alone or in colonies. They can help you or hurt you. Most important fact is that they make up the largest number of living organisms on the planet. It helps to be that small. It's not millions, billions, or trillions. There are trillions of trillions of trillions of microbes around the Earth. Maybe more.
Calling all Microscopes
As with all of science, discovery in biology is a huge thing. While microbes like bacteria, fungi, some algae, and protozoa have always existed, scientists did not always know they were there. They may have seen a mushroom here or there, but there were hundreds of thousands of species to be discovered.
It took one invention to change the way we see the world of microbes – the microscope. In 1673, Anton von Leeuwenhoek put a couple of lenses together and was able to see a completely new world. He made the first microscope. It wasn't that impressive, but it started a whole history of exploration. More important to us, scientists were eventually able to discover the cause and cure of many diseases.
Too Many to Count, Too Small to Find
We'll give the big overview on the variety of microorganisms here. There is no simple explanation of a microbe besides the fact that they are small. The list goes on. Just remember that there is a lot of variety going on here.
They can be heterotrophic or autotrophic. These two terms mean they either eat other things (hetero) or make food for themselves (auto). Think about it this way: plants are autotrophic and animals are heterotrophic.
They can be solitary or colonial. A protozoan like an amoeba might spend its whole life alone, cruising through the water. Others, like fungi, work together in colonies to help each other survive.
They can reproduce sexually or asexually. Sometimes the DNA of two microbes mixes and a new one is created (sexual reproduction). Sometimes a microbe splits into two identical pieces by itself (asexual reproduction).
Biology Facts
Increase your biology knowledge with this great collection of interesting biology facts. Learn about cells, DNA, ecology, natural selection, bacteria, viruses, yeast, evolution, cloning and much more.
People that study biology are known as biologists.
Australia's Great Barrier Reef is the largest living structure on Earth. Reaching over 2000 kilometres (1240 miles) in length.
The first person to see a live cell with a microscope was Antonie van Leeuwenhoek, in 1674.
Ecology is the study of ecosystems and how organisms interact with their environment.
While some bacteria can make you sick, others have positive benefits such as helping you digest food or even make yoghurt.
Moulds, yeasts and mushrooms are types of fungus.
The common cold is a type of virus.
Viruses can be treated with antiviral drugs.
Bacteria are extremely small and are made up of just one cell.
Bacterial infections can be treated with antibiotics.
Animals that eat plants as their primary food source are known as herbivores.
Endangered species are those that are in danger of being completely wiped out, they include blue whales, tigers and pandas. Without protection these species may eventually become extinct.
Born on July 5th 1996, Dolly the sheep was the first mammal to be cloned from an adult cell.
When the DNA of an organism changes and results in a new trait (characteristic) it is known as mutation.
French chemist and microbiologist Louis Pasteur was well known for inventing a process to stop various foods and liquids making people sick. Called Pasteurization, it reduces the amount of microorganisms that could lead to disease without having a noticeable effect on taste and quality in a way which methods such as sterilization might.
Charles Darwin developed the idea of natural selection, sometimes called survival of the fittest. It is a process that involves living things with favorable traits being more likely to reproduce, passing on their favorable traits to future generations.
10 Most Mind-Bending Physics Facts
For some of us, physics was something we dreaded at school, abandoning our studies in it at the earliest opportunity, all before reaching adulthood and realising that this particular branch of science is arguably the coolest. Fortunately, there are graduates, postgrads and doctors who had more foresight than people like this humble writer and made the study of physics their life's work. Here are some of the unbelievably cool things about physics that we have learned because of people like them.
1. Relativity Makes Space Travellers Younger (Kinda)
Both velocity and gravity have an effect on the speed of time; the higher they are, the slower time passes. Astronauts aboard the International Space Station (ISS) (who are in reduced gravity compared to people on Earth but travelling at increased speed around it) experience time more slowly, at a rate of roughly 1 second 'lost' every 747 days.
2. Without E=MC2 GPS Would Malfunction
The satellite navigation in your car or on your phone relies on a series of geostationary satellites to pinpoint your location, exchanging data using radio waves. Because of the theory of relativity, the speed at which the satellites' onboard clocks tick is around 38,000 nanoseconds faster than clocks on the ground. Every time data is sent to the receiving device, a calculation must be applied to correct the timings to within the required 20-30 nanosecond accuracy.
3.'The Speed Of Light' Isn't Constant
Most people will have heard about the speed of light (c. 671 million miles per hour), which according to all accepted laws of Physics is the fastest that anything can travel. In actual fact, this figure refers only to the speed of light in a vacuum. Really, light is slowed whenever it passes through something, being measured travelling as slowly as just 38 miles per hour at absolute zero (-273.15C) through ultra-cooled rubidium.
4. Humanity Could Fit In A Sugar Cube
Remember when you learned all about the basic structure of the atom – protons, neutrons, electrons? You might recall there was a lot of empty space, and you'd be right. Most of atoms is just empty space, so much so that if you gathered the entire human race together and removed the empty space of all the atoms that make them up you would be left with something no larger than a sugar cube. Incidentally…
5. That Sugar Cube Would Weigh Five Billion Tons
Why? Because all that empty space doesn't have any mass, so the sugar cube of humanity would be extremely dense. It's the same principle behind why 1kg of bricks and 1kg of feathers weighs the same, but a box of bricks is denser and has more mass than an equally-sized box of feathers.
6. We Don't Know What Most Of The Universe Is
Despite all the advances made in astrophysics in recent years, not least the discovery of various exoplanets beyond our solar system, we don't know what makes up the majority of the universe. It is possible to make reasonable estimates of the mass of the universe, except that visible matter (stars, planets, stellar objects) only accounts for 2% of that; what exactly makes up the rest – so-called 'dark matter' and 'dark energy' – remains a mystery.
7. Go Fast, Gain Weight
Our old friend relativity explains this one as well – mass and energy are equivalent, meaning that as you add energy to a moving object (i.e. increase speed) then that object's mass increases. At 'normal' speeds, this mass gain is pretty negligible, but as you approach the speed of light mass begins to increase dramatically. In case you're wondering why sprinters and cars and aeroplanes don't get heavier because of this, don't worry – the increase in mass as a result of increased speed is only temporary.
8. You Could Be A Walking H-Bomb
The First Law of Thermodynamics holds that in any situation, the total amount of energy in will equal the exact same amount of energy out. As well as meaning that you can't create energy out of nothing, this law means that you also can not destroy energy. So what happened to all the energy that came from what you put in your own body? The short answer is that most of it remains stored within your body, an average of 7×1018 joules – this amount of energy, if released all at once, would have the same power as 30 hydrogen bombs.
9. You Might Already Have Read This
According to Big Bang cosmology, the universe is constantly expanding. One school of thought suggests that this expansion must eventually not only slow down, but also go into reverse and cause a 'Big Crunch'. What would happen then is a mystery, but if there is indeed a cycle of 'bang, expansion, contraction, collapse, bang', it may well be that the universe plays out in exactly the same way. You might have been born, lived, read this article, lived some more and died in exactly the same way over and over again and not even know it.
10. Another You Might Have Died Reading This
According to the multiverse theory (yes, it's not just a Family Guy thing), there are an infinite number of universes existing parallel to one another, with each differing slightly and every possible scenario being played out in its own universe. This would mean that in at least one universe, a freak accident meant that you were hit by a meteor and killed before finishing this sentence. In another universe, you wouldn't have even read this article in the first place, because I would have been hit by a meteor and killed before finishing writing it. For a classic 90s TV take on this theory, go look up Sliders on Youtube.
20 Amazing Facts About the Human Body
The appendix gets a bad press. It is usually treated as a body part that lost its function millions of years ago. All it seems to do is occasionally get infected and cause appendicitis. Yet recently it has been discovered that the appendix is very useful to the bacteria that help your digestive system function. They use it to get respite from the strain of the frenzied activity of the gut, somewhere to breed and help keep the gut's bacterial inhabitants topped up. So treat your appendix with respect.
Practically everything we experience is made up of molecules. These vary in size from simple pairs of atoms, like an oxygen molecule, to complex organic structures. But the biggest molecule in nature resides in your body. It is chromosome 1. A normal human cell has 23 pairs of chromosomes in its nucleus, each a single, very long, molecule of DNA. Chromosome 1 is the biggest, containing around 10bn atoms, to pack in the amount of information that is encoded in the molecule.
It is hard to grasp just how small the atoms that make up your body are until you take a look at the sheer number of them. An adult is made up of around 7,000,000,000,000,000,000,000,000,000 (7 octillion) atoms.
It might seem hard to believe, but we have about the same number of hairs on our bodies as a chimpanzee, it's just that our hairs are useless, so fine they are almost invisible. We aren't sure quite why we lost our protective fur. It has been suggested that it may have been to help early humans sweat more easily, or to make life harder for parasites such as lice and ticks, or even because our ancestors were partly aquatic.
But perhaps the most attractive idea is that early humans needed to co-operate more when they moved out of the trees into the savanna. When animals are bred for co-operation, as we once did with wolves to produce dogs, they become more like their infants. In a fascinating 40-year experiment starting in the 1950s, Russian foxes were bred for docility. Over the period, adult foxes become more and more like large cubs, spending more time playing, and developing drooping ears, floppy tails and patterned coats. Humans similarly have some characteristics of infantile apes – large heads, small mouths and, significantly here, finer body hair.
Goosepimples are a remnant of our evolutionary predecessors. They occur when tiny muscles around the base of each hair tense, pulling the hair more erect. With a decent covering of fur, this would fluff up the coat, getting more air into it, making it a better insulator. But with a human's thin body hair, it just makes our skin look strange.
Similarly we get the bristling feeling of our hair standing on end when we are scared or experience an emotive memory. Many mammals fluff up their fur when threatened, to look bigger and so more dangerous. Humans used to have a similar defensive fluffing up of their body hairs, but once again, the effect is now ruined. We still feel the sensation of hairs standing on end, but gain no visual bulk.
If sci-fi movies were to be believed, terrible things would happen if your body were pushed from a spaceship without a suit. But it's mostly fiction. There would be some discomfort as the air inside the body expanded, but nothing like the exploding body parts Hollywood loves. Although liquids do boil in a vacuum, your blood is kept under pressure by your circulatory system and would be just fine. And although space is very cold, you would not lose heat particularly quickly. As Thermos flasks demonstrate, a vacuum is a great insulator.
In practice, the thing that will kill you in space is simply the lack of air. In 1965 a test subject's suit sprang a leak in a Nasa vacuum chamber. The victim, who survived, remained conscious for around 14 seconds. The exact survival limit isn't known, but would probably be one to two minutes.
The atoms that make up your body are mostly empty space, so despite there being so many of them, without that space you would compress into a tiny volume. The nucleus that makes up the vast bulk of the matter in an atom is so much smaller than the whole structure that it is comparable to the size of a fly in a cathedral. If you lost all your empty atomic space, your body would fit into a cube less than 1/500th of a centimetre on each side. Neutron stars are made up of matter that has undergone exactly this kind of compression. In a single cubic centimetre of neutron star material there are around 100m tons of matter. An entire neutron star, heavier than our sun, occupies a sphere that is roughly the size across of the Isle of Wight.
The atoms that make up matter never touch each other. The closer they get, the more repulsion there is between the electrical charges on their component parts. It's like trying to bring two intensely powerful magnets together, north pole to north pole. This even applies when objects appear to be in contact. When you sit on a chair, you don't touch it. You float a tiny distance above, suspended by the repulsion between atoms. This electromagnetic force is vastly stronger than the force of gravity – around a billion billion billion billion times stronger. You can demonstrate the relative strength by holding a fridge magnet near a fridge and letting go. The electromagnetic force from the tiny magnet overwhelms the gravitational attraction of the whole Earth.
Every atom in your body is billions of years old. Hydrogen, the most common element in the universe and a major feature of your body, was produced in the big bang 13.7bn years ago. Heavier atoms such as carbon and oxygen were forged in stars between 7bn and 12bn years ago, and blasted across space when the stars exploded. Some of these explosions were so powerful that they also produced the elements heavier than iron, which stars can't construct. This means that the components of your body are truly ancient: you are stardust.
One of the mysteries of science is how something as apparently solid and straightforward as your body can be made of strangely behaving quantum particles such as atoms and their constituents. If you ask most people to draw a picture of one of the atoms in their bodies, they will produce something like a miniature solar system, with a nucleus as the sun and electrons whizzing round like planets. This was, indeed, an early model of the atom, but it was realised that such atoms would collapse in an instant. This is because electrons have an electrical charge and accelerating a charged particle, which is necessary to keep it in orbit, would make it give off energy in the form of light, leaving the electron spiralling into the nucleus.
In reality, electrons are confined to specific orbits, as if they ran on rails. They can't exist anywhere between these orbits but have to make a "quantum leap" from one to another. What's more, as quantum particles, electrons exist as a collection of probabilities rather than at specific locations, so a better picture is to show the electrons as a set of fuzzy shells around the nucleus.
When you see blood oozing from a cut in your finger, you might assume that it is red because of the iron in it, rather as rust has a reddish hue. But the presence of the iron is a coincidence. The red colour arises because the iron is bound in a ring of atoms in haemoglobin called porphyrin and it's the shape of this structure that produces the colour. Just how red your haemoglobin is depends on whether there is oxygen bound to it. When there is oxygen present, it changes the shape of the porphyrin, giving the red blood cells a more vivid shade.
Surprisingly, not all the useful DNA in your chromosomes comes from your evolutionary ancestors – some of it was borrowed from elsewhere. Your DNA includes the genes from at least eight retroviruses. These are a kind of virus that makes use of the cell's mechanisms for coding DNA to take over a cell. At some point in human history, these genes became incorporated into human DNA. These viral genes in DNA now perform important functions in human reproduction, yet they are entirely alien to our genetic ancestry.
On sheer count of cells, there is more bacterial life inside you than human. There are around 10tn of your own cells, but 10 times more bacteria. Many of the bacteria that call you home are friendly in the sense that they don't do any harm. Some are beneficial.
In the 1920s, an American engineer investigated whether animals could live without bacteria, hoping that a bacteria-free world would be a healthier one. James "Art" Reyniers made it his life's work to produce environments where animals could be raised bacteria-free. The result was clear. It was possible. But many of Reyniers's animals died and those that survived had to be fed on special food. This is because bacteria in the gut help with digestion. You could exist with no bacteria, but without the help of the enzymes in your gut that bacteria produce, you would need to eat food that is more loaded with nutrients than a typical diet.
Depending on how old you are, it's pretty likely that you have eyelash mites. These tiny creatures live on old skin cells and the natural oil (sebum) produced by human hair follicles. They are usually harmless, though they can cause an allergic reaction in a minority of people. Eyelash mites typically grow to a third of a millimetre and are near-transparent, so you are unlikely to see them with the naked eye. Put an eyelash hair or eyebrow hair under the microscope, though, and you may find them, as they spend most of their time right at the base of the hair where it meets the skin. Around half the population have them, a proportion that rises as we get older.
Your eyes are very sensitive, able to detect just a few photons of light. If you take a look on a very clear night at the constellation of Andromeda, a little fuzzy patch of light is just visible with the naked eye. If you can make out that tiny blob, you are seeing as far as is humanly possible without technology. Andromeda is the nearest large galaxy to our own Milky Way. But "near" is a relative term in intergalactic space – the Andromeda galaxy is 2.5m light years away. When the photons of light that hit your eye began their journey, there were no human beings. We were yet to evolve. You are seeing an almost inconceivable distance and looking back in time through 2.5m years.
Despite what you've probably been told, you have more than five senses. Here's a simple example. Put your hand a few centimetres away from a hot iron. None of your five senses can tell you the iron will burn you. Yet you can feel that the iron is hot from a distance and won't touch it. This is thanks to an extra sense – the heat sensors in your skin. Similarly we can detect pain or tell if we are upside down.
Another quick test. Close your eyes and touch your nose. You aren't using the big five to find it, but instead proprioception. This is the sense that detects where the parts of your body are with respect to each other. It's a meta-sense, combining your brain's knowledge of what your muscles are doing with a feel for the size and shape of your body. Without using your basic five senses, you can still guide a hand unerringly to touch your nose.
Just like a chicken, your life started off with an egg. Not a chunky thing in a shell, but an egg nonetheless. However, there is a significant difference between a human egg and a chicken egg that has a surprising effect on your age. Human eggs are tiny. They are, after all, just a single cell and are typically around 0.2mm across – about the size of a printed full stop. Your egg was formed in your mother – but the surprising thing is that it was formed when she was an embryo. The formation of your egg, and the half of your DNA that came from your mother, could be considered as the very first moment of your existence. And it happened before your mother was born. Say your mother was 30 when she had you, then on your 18th birthday you were arguably over 48 years old.
We are used to thinking of genes as being the controlling factor that determines what each of us is like physically, but genes are only a tiny part of our DNA. The other 97% was thought to be junk until recently, but we now realise that epigenetics – the processes that go on outside the genes – also have a major influence on our development. Some parts act to control "switches" that turn genes on and off, or program the production of other key compounds. For a long time it was a puzzle how around 20,000 genes (far fewer than some breeds of rice) were enough to specify exactly what we were like. The realisation now is that the other 97% of our DNA is equally important.
If you are like most people, you will locate your conscious mind roughly behind your eyes, as if there were a little person sitting there, steering the much larger automaton that is your body. You know there isn't really a tiny figure in there, pulling the levers, but your consciousness seems to have an independent existence, telling the rest of your body what to do.
In reality, much of the control comes from your unconscious. Some tasks become automatic with practice, so that we no longer need to think about the basic actions. When this happens the process is handled by one of the most primitive parts of the brain, close to the brain stem. However even a clearly conscious action such as picking up an object seems to have some unconscious precursors, with the brain firing up before you make the decision to act. There is considerable argument over when the conscious mind plays its part, but there is no doubt that we owe a lot more to our unconscious than we often allow.
The picture of the world we "see" is artificial. Our brains don't produce an image the way a video camera works. Instead, the brain constructs a model of the world from the information provided by modules that measure light and shade, edges, curvature and so on. This makes it simple for the brain to paint out the blind spot, the area of your retina where the optic nerve joins, which has no sensors. It also compensates for the rapid jerky movements of our eyes called saccades, giving a false picture of steady vision.
But the downside of this process is that it makes our eyes easy to fool. TV, films and optical illusions work by misleading the brain about what the eye is seeing. This is also why the moon appears much larger than it is and seems to vary in size: the true optical size of the moon is similar to a hole created by a hole punch held at arm's length.
Biology is Harder than Physics?
Biological processes of course are consequences of physics and chemistry, which is why we require our biology students to study the physical sciences. But organisms are also historical entities, and that's where the complexities arise. The facts of physics and chemistry are constant across time and space. Any one carbon atom is the same as any other, and today's carbon atoms are the same as those of a billion years ago. But each organism is different. That's not just a statement that fruit flies are different from house flies. Rather, each fruit fly is different from every other fruit fly alive today, and from every other fruit fly that ever lived, and it's the differences that make biology both thrilling and hard.
No disagreements from me here. The laws which govern physics and chemistry are contant across the universe (though there is some debate as to their constancy in time). Without the strict adherence to the laws we observe, physics and chemistry would be near impossible to understand. It is lucky for biology that this is how the world works, because, as Rosie notes, biology depends on it!
Skipping ahead, here's where I get confused:
Even genetically identical cells are not functionally identical. When a cell divides its molecules are randomly distributed between the two daughters; because 'randomly' does not mean 'evenly', these daughters will have inherited different sets of the proteins and RNAs that carry out their functions. And even if the two cells had identical contents, these contents would still have different interactions – repressors bump into cofactors at different times, DNA polymerase slips or doesn't slip at different points in its progress along a chromosome. Understanding the how and why of biological phenomena thus requires us to consider historical and ecological factors that are many orders of magnitude more complex than those of physical systems.
When trying to understand biological systems (nay, any kind of system, be it a crystal or a batch of cells), much ultimately depends on the type of measurement. Every measurement does not need to take into account the histories and ecological factors that make up every individual cell – it is impossible to know them to the required resolution that such data would be useful. When and where a DNA polymerase may stall on the chromosome in a particular cell of a mL culture containing billions upon billions of cells is effectively irrelevant for a huge number of interesting experiments I might want to do with those cells — say, the study of expression of a particular gene with a gene chip.
The critical word is probably 'population'. Biologists rarely try to define it, but they use the term everywhere to refer to similar but not identical organisms or cells (or even molecules) that interact in some way. 'Population thinking', the realization that species are populations, not pure types, is said to have been key to Darwin's insight that members of a species undergo natural selection. And population thinking is probably what makes biology so much more complex than the physical sciences.
Here's where I think my ultimate displeasure with the post lies. That biology is more complex than physics (though what exactly is limited to the realm of physics is now very much in question) is a reasonable statement: the most common biological molecules are much too complicated to apply something like the Schroedinger Equation and expect to understand anything about them, but "complex" and "difficult" are not the same thing. That physics has traditionally been confined to the well-defined and "simple" systems like infinite lattices of identical carbon atoms, doesn't make it "easier" to study than biology. I don't even know what it could mean for one field of science to be "easier" than another, given that everyone studying a science is different, like, as Rosie mentions above, how each fruit fly is different from every other fruit fly. Some people find the mathematics required to understand physical systems extremely difficult, while others don't have the required attention to detail to perform a successful experiment in a biology lab. To do any kind of science, however, it is the same: you require critical thinking and quantitative analysis of experiments to make any sense of your results. This is true from particle physics all the way up to ecology.
Rosie's opening paragraph ends with the following: In reality biology is much more complex than the physical sciences, and understanding it requires more, not less, brain work.
Is Biology Reducible to the Laws of Physics?
Alex Rosenberg is unusual among philosophers of biology in adhering to the view that everything occurs in accordance with universal laws, and that adequate explanations must appeal to the laws that brought about the thing explained. He also believes that everything is ultimately determined by what happens at the physical level—and that this entails that the mind is "nothing but" the brain. For an adherent of this brand of physicalism, it is fairly evident that if there are laws at "higher" levels—laws of biology, psychology or social science—they are either deductive consequences of the laws of physics or they are not true. Hence Rosenberg is committed to the classical reductionism that aims to explain phenomena at all levels by appeal to the physical.
It is worth mentioning that, as Rosenberg explains, these views are generally assumed by contemporary philosophers of biology to be discredited. The reductionism that they reject, he says,
holds that there is a full and complete explanation of every biological fact, state, event, process, trend, or generalization, and that this explanation will cite only the interaction of macromolecules to provide this explanation.
Such views have been in decline since the 1970s, when David Hull (The Philosophy of Biological Science [1974]) pointed out that the relationship between genetic and phenotypic facts was, at best, "many/many": Genes had effects on numerous phenotypic features, and phenotypic features were affected by many genes. A number of philosophers have elaborated on such difficulties in subsequent decades.
The question then is whether Rosenberg's latest book, Darwinian Reductionism: Or, How to Stop Worrying and Love Molecular Biology, constitutes a useful attack on a dogmatic orthodoxy or merely represents a failure to understand why the views of an earlier generation of philosophers of science have been abandoned. Unfortunately I fear the latter is the case. More specifically, his portrayal of the genome as a program directing development, which is the centerpiece of his reductionist account of biology, discloses a failure to appreciate the complex two-way interactions between the genome and its molecular environment that molecular biologists have been elaborating for the past several decades.
In earlier work, Rosenberg accepted the consensus among philosophers of biology that biology couldn't be reduced to chemistry or physics. But whereas most philosophers saw this as a problem for philosophy of science, and for traditional models of reduction, Rosenberg concluded that it was a problem for biology, a problem indicating that the field's purported explanations were neither fundamental nor true.
However, in his most recent book Rosenberg is more sanguine about biology. As the title suggests, the new idea is that recognition of the pervasiveness of Darwinism in biology will enable us to assert reductionism after all. Rosenberg is an admirer of Dobzhansky's famous remark that nothing in biology makes sense except in the light of evolution:
Biology is history, but unlike human history, it is history for which the "iron laws" of historical change have been found, and codified in Darwin's theory of natural selection. . . . [T]here are no laws in biology other than Darwin's. But owing to the literal truth of Dobzhansky's dictum, these are the only laws biology needs.
The suggestion is that something Rosenberg calls "the principle of natural selection" is actually a fundamental physical law. Natural selection, according to him, is not a statistical consequence of the operation of many other physical (or perhaps higher-level) laws, as most philosophers of biology believe. Rather, it is a new and fundamental physical law to be added to those already revealed by chemistry and physics. I won't try to recount Rosenberg's arguments for this implausible position.
The largest part of the book motivates reductionism from a quite different direction by defending the view that genes literally embody a program that produces development. Rosenberg introduces this view by recounting some work on the development of insect wings. There is a rather disturbing tendency in this exegesis to suggest an imputation of agency to the genes that are implementing this program. He says that the genes fringe and serrate "form the wing margin," for example, and "wingless builds wings." He also maintains that in Drosophila, "2500 genes . . . are under direct or indirect control of eyeless." As the last two examples illustrate and Rosenberg explains, genes are frequently identified by what doesn't happen when they are deleted. But Rosenberg seems quite untroubled by the dubious inference from what doesn't happen to the conclusion that making this happen is what the genes "do" when in place. These reifications provoke a range of worries, but at a minimum, a defense of such ways of speaking will need to address another growing philosophical consensus to which Rosenberg is an exception, that the gene is a concept that no longer has an unproblematic place in contemporary biology.
Rosenberg does attempt a defense of the gene, but his arguments are unconvincing. The biggest problem is that he never says what he means by a gene. He refers uncritically to estimates of the number of genes in the human genome; although he does outline some of the difficulties with these estimates, he does not seem to appreciate their force. As a positive contribution, it appears that all he has to offer is the proposal that genes are "sculpted" out of the genome by natural selection to serve particular functions. The central point of critics of the gene concept is that functional decomposition identifies multiple overlapping and crosscutting parts of genomes. The "open reading frames" to which biologists refer when they count the genes in the human genome not only can overlap but are sometimes read in both directions. Subsequent to transcription they are broken into different lengths, edited, recombined and so on, so that one "gene" may be the ancestor of hundreds or even thousands of final protein products. Sophisticated would-be reductionists, such as Kenneth Waters, have tried to accommodate this point. Rosenberg seems just to ignore it as happily as he ignores most of the literature that has expounded the difficulties (for example, What Genes Can't Do, by Lenny Moss [2003], and The Concept of the Gene in Development and Evolution, edited by Peter Beurton, Raphael Falk and Hans-Jörg Rheinberger [2000]).
The problem might have been ameliorated if Rosenberg had paid more attention to the increasingly diverse constituents recognized in the genome apart from the genes he needs to run his programs. The lack of concern with the genome is highlighted, for example, when in the course of a single paragraph he says that sculpting of the genome by natural selection has resulted in "a division mainly into genes" and refers to 95 percent of the human DNA sequence appearing to be "mere junk" (another hypothesis that has been widely rejected). It is conceivable that Rosenberg means to define genome so as to exclude the junk, although I have never encountered such a usage before. What is clear, though, is that he sees the genome merely as a repository for the informationally conceived genes supposed to run the developmental program. Attention to the increasingly understood complexities of the genome as a material object would have made the misguided nature of the enterprise much clearer.
A further problem is that some of the biology in the book is dated. For example, Rosenberg says that "there are about 30,000 to 60,000 genes in our genome," but in fact there is a fairly stable consensus now that the number is about 23,000. More striking is his remark that alternative splicing is "uncommon but not unknown," whereas it is actually widely accepted that such splicing occurs in more than 70 percent of human genes. Although Rosenberg has researched some biological topics in detail, the book contains other lapses as well. He appears to be unaware, for instance, that methylation occurs in contexts other than sexual imprinting. And I was struck by his remark that the world is now mainly populated by sexual species; in fact, the overwhelming majority of organisms now, as ever, are prokaryotes and (relatively) simple asexual eukaryotes. It is admittedly difficult or impossible to stay fully au courant with the latest in molecular biology, but a careful reading of the manuscript by a practitioner would have been very helpful.
Because I have been involved for many years in criticism of the earlier orthodoxy that Rosenberg continues to defend, it is not surprising that I am unconvinced by his reactionary argument. And it is of course very often a good thing for philosophers to confront the orthodoxies of their discipline. But the standards for undermining orthodoxy are inevitably high, and Rosenberg does not come close to meeting them.
The subtitle invites us to learn to love molecular biology. Many of the philosophers whom Rosenberg's views contradict greatly admire the achievements of molecular biology. Love, however, is well known for being blind. I would encourage Rosenberg to settle for admiration.
Biology is Different?
It may have occurred to you at one time or another that there are some subtle differences between Biology as a science and Chemistry, Physics, and Mathematics. Obviously, the main difference is that Biology deals with living organisms, but the ramifications of this fact go beyond just the subject matter, because it also affects the nature of the scientific methods employed by biologists.
The evolutionary biologist Ernst Mayr has written extensively on the philosophical implications of evolutionary biology and has discussed (Mayr, 1982) what he sees as the fundamental points that should be incorporated into a philosophy for the biological sciences. That these principles have not been recognized more clearly is because, according to Mayr, philosophers of science continue to use the physical sciences (especially Physics) as a model for all of the sciences. The points raised by Mayr are summarized in the table below and are as follows:
Understanding Organisms: One approach to understanding a phenomenon is to reduce it to its fundamental aspects, and, by understanding each component, you can gain some appreciation of the overall process. This approach, often referred to as reductionism, is useful, especially in the physical sciences, where, for example, a knowledge of the behavior of individual atoms allows you to predict the dynamics of an reaction system. However, the hierarchical organization of biological systems makes it impossible to understand all aspects of even a single organism by studying each of its components. Furthermore, there are certain biological processes, like Natural Selection, which cannot be predicted based on only a knowledge of Physics and Chemistry. In other words, the entire range of material phenomena are to be found in biological systems, whereas Physics and Chemistry only deal with a subset of these phenomena.
History: There are many disciplines, besides History itself, where unique historical events play a critical role. Astronomy and Geology, for example, are often concerned with individual historical events. In Biology, however, we study not only historical events but also the organisms which have been either directly or indirectly shaped by those events. A good case in point is the effect of the extinction of the dinosaurs on subsequent mammalian diversification. This historical aspect of biology is compounded by the fact that the DNA within each organism is in fact an historical record of the ancestor-descendant relationships of that particular individual.
Principles that should be included in the formation of a philosophy for the biological sciences. From Mayr (1982).
1. That a full understanding of organisms cannot be secured through the theories of Physics and
Chemistry alone.
2. That the historical nature of organisms must be fully considered, in particular their possession
of an historically acquired genetic program.
3. That individuals at most hierarchical levels, from the cell up, are unique and form populations,
the variance of which is one of their major characteristics.
4. That there are two biologies, functional biology, which asks proximate questions, and
evolutionary biology, which asks ultimate questions.
5. That the history of biology has been dominated by the establishment of concepts and by their
maturation, modification, and – occasionally – their rejection.
6. That the patterned complexity of living systems is hierarchically organized and that higher
levels in the hierarchy are characterized by the emergence of novelties.
7. That observation and comparison are methods in biological research that are fully as scientific
and heuristic as the experiment.
8. That an insistence on the autonomy of biology does not mean an endorsement of vitalism,
orthogenesis, or any other theory that is in conflict with the laws of chemistry or physics.
Uniqueness: One of the things that enables research in the physical sciences to be so efficient and precise is the fact that there is so little variability in many of the entities studied. For example, all atoms of a particular isotope of carbon behave in exactly the same way, and this means that an organic chemist can readily predict the outcome of a particular reaction. Contrast this situation with that of a biologist, who, regardless of his or her field must deal with the fact that the subjects being investigated are not all the same, but instead differ to some degree because they have different genotypes. Even studies at the biochemical level must take into account the possible existence of more than one protein variant in a given system. The variance that is observed in physical systems is treated as either an error in measurement or as the result of some random "noise" factor, but in biological research the observed variance is a reflection of a fundamental aspect of living systems.
Two Approaches to Biology: The tendency to look at some aspects of biology as being somehow less "scientific" than the physical sciences is not restricted to philosophers of science who use the physical sciences as their model; the same attitude can be found within biology because there are two main ways in which biologists can approach their research. In studying a particular phenomenon, you can ask either proximate or ultimate questions. The proximate aspects of a phenomenon are usually related to the question "How…?", while the ultimate issues are usually addressed by "Why…?". For example, it is well known that male frogs call during the mating season in order to attract females. You could study this phenomenon by describing the vocalization mechanism of the males, the frequencies of the sounds produced, and the auditory apparatus of the females. Each of these is basically a functional, physiological question, but there is the other approach to the same question which is to determine the significance of what is happening. One simple explanation is that these calls are the only way in which the sexes can find each other in the dark. However, an increasing amount of research shows that these calls are critical to the process of mate selection and subsequent mating success (e. g., Ryan, 1990). Addressing this issue requires that we determine the evolutionary processes associated with the mating system – the fitness consequences of mating with a particular male, the correlation, if any, between male calling frequency and fitness, etc. Obviously, studying this aspect of the phenomenon is not as clear cut as the physiological questions, but it is still a legitimate scientific inquiry. In fact, those who deal with proximate questions in biology often find that the more they learn about their systems, the more they must concern themselves with the ultimate, evolutionary issues.
Concepts in Biology: The model of the scientific method that is derived from the physical sciences leaves one with the impression that the goal of science is to generate "laws" (e. g., the statements of Newton and Kepler on general and planetary motion, respectively). Laws in this sense are statements of fact that have been demonstrated to fit all known cases. Biologists have occasionally suffered from a desire to emulate the physical sciences by establishing laws (e. g., Ernst Haeckel's Biogenetic Law – "Ontogeny recapitulates Phylogeny"), but the historical component and intrinsic variability of biological systems make such universal statements impossible. Biological science advances by developing general concepts which are used to guide our approach to particular phenomena. Natural Selection is an example of a concept, and, while some have discussed it from the perspective of a law (Reed, 1981), it is merely a formal generalization about the interactions among the environment, organisms, and the genotypes of those organisms in terms of the impact of these interactions on genotypic frequencies. The formal generalizations of biology always include exceptions that "prove the rule" and result in the modification and refinement of the concepts over time.
Hierarchy: Students in Biology are well acquainted with the listing of the biological hierarchy that runs from molecules and cells to ecosystems and the biosphere, but few ever stop to think about the ramifications of this hierarchy for the study of biological systems. The existence of this structure in biological systems means that we must deal with the fact of emergent properties at each level. The concept of emergence is the idea that the entire system may exhibit properties that are not deducible from a knowledge of the individual components of the system. This idea is often summarized by the phrase "the whole is greater than the sum of the parts". The existence of emergent properties in living systems is what limits the usefulness of the reductionist approach to biology. The recognition of the hierarchical structure of life on this planet has caused some to suggest that major areas of biological investigation should operate formally with this structure in mind (e. g., Eldredge, 1985; O'Neill, et al., 1986).
Observation and Comparison: The introductory textbook description of the scientific method has scientists operating by making observations, formulating hypotheses, and conducting experiments to test their hypotheses. This is an accurate description of how to study common, contemporary phenomena, but how, for example, do you go about scientifically studying the extinction of the dinosaurs? The notion of the laboratory experiment as the scientific method is so ingrained that even biologists who study proximate questions in existing organisms tend to discount the efforts of those who conduct evolutionary and/or ecological research. However, evolutionary biologists can – and do – formulate hypotheses, but only some of these hypotheses are testable through controlled laboratory or field experiments. In many instances, evolutionary hypotheses can be tested only by comparing populations or species under different sets of conditions, or, in the case of past events, looking for evidence related to corollaries of the main hypothesis. For example, if an asteroid impact caused the extinction of the dinosaurs at the end of the Cretaceous (Alvarez, et al., 1980), then there should be several geological and paleontological lines of evidence which would support this scenario.
Biology as an Autonomous Science: Whenever people argue that there is an intrinsic difference between living and non-living systems, they leave themselves open to the charge that they are advocating either vitalism or orthogenesis. Vitalism is the discredited notion that what makes living systems different is their possession of some "vital force" that when removed from the system just leaves you with a mass of organic molecules. This concept was most recently popularized in the 20th century by the French philosopher Henri Bergson. Orthogenesis is a related concept which holds that the evolutionary process is somehow goal-directed to produce progressively higher levels of perfection and complexity. The application of this concept to evolution has a history that stretches from Lamarck to the theological writings of Teilhard de Chardin. As you have seen, there is no need to postulate the existence of some metaphysical force to explain the difference between living and non-living systems. The reason why Biology differs from the physical sciences is because of the characteristics of living systems which are, among others: (1) the importance of history in organic evolution; (2) the possession of a structured, inheritable genetic program; (3) the hierarchical structure of living systems, and the existence of emergent properties at almost every level; (4) the fact that certain processes (e. g., Natural Selection) only occur in living systems.
Biophysics is a bridge between biology and physics.
Biology studies life in its variety and complexity. It describes how organisms go about getting food, communicating, sensing the environment, and reproducing. On the other hand, physics looks for mathematical laws of nature and makes detailed predictions about the forces that drive idealized systems. Spanning the distance between the complexity of life and the simplicity of physical laws is the challenge of biophysics. Looking for the patterns in life and analyzing them with math and physics is a powerful way to gain insights.
Biophysics looks for principles that describe patterns. If the principles are powerful, they make detailed predictions that can be tested.
What do biophysicists study?
All of Biology is Fair Game.
Biophysicists study life at every level, from atoms and molecules to cells, organisms, and environments. As innovations come out of physics and biology labs, biophysicists find new areas to explore where they can apply their expertise, create new tools, and learn new things. The work always aims to find out how biological systems work. Biophysicists ask questions, such as:
How do protein machines work? Even though they are millions of times smaller than everyday machines, molecular machines work on the same principles. They use energy to do work. The kinesin machine shown here is carrying a load as it walks along a track. Biophysics reveals how each step is powered forward.
How do systems of nerve cells communicate? Biophysicists invented colored protein tags for the chemicals used by cells. Each cell takes on a different color as it uses the tagged chemicals, making it possible to trace its many pathways.
How do proteins pack DNA into viruses? How do viruses invade cells? How do plants harness sunlight to make food?
Biophysics studies life at every level, from atoms and molecules to cells, organisms, and environments.
How essential is biophysics to progress in biology?
Biophysics discovers how atoms are arranged to work in DNA and proteins.
Protein molecules perform the body's chemical reactions. They push and pull in the muscles that move your limbs. Proteins make the parts of your eyes, ears, nose, and skin that sense your environment. They turn food into energy and light into vision. They are your immunity to illness. Proteins repair what is broken inside of cells, and regulate growth. They fire the electrical signals in your brain. They read the DNA blueprints in your body and copy the DNA for future generations.
Biophysicists are discovering how proteins work. These mysteries are solved part by part. To learn how a car works, you first need to know how the parts fit together. Now, thanks to biophysics, we know exactly where the thousands of atoms are located in more than 50,000 different proteins. Each year, over a million scientists and students from all over the world, from physicists to medical practitioners, use these protein structures for discovering how biological machines work, in health and also in diseases.
Variations in proteins make people respond to drugs differently. Understanding these differences opens new possibilities in drug design, diagnosis, and disease control. Soon, medicines will be tailored to each individual patient's propensity for side effects.
Biophysics revealed the structure of DNA
Experiments in the 1940's showed that genes are made of a simple chemical–DNA. How such a simple chemical could be the molecule of inheritance remained a mystery until biophysicists discovered the DNA double helix in 1953.
The structure of DNA was a great watershed. It showed how simple variations on a single chemical could generate unique individuals and perpetuate their species.
Biophysics showed how DNA serves as the book of life. Inside of cells, genes are opened, closed, read, translated, and copied, just like books. The translation leads from DNA to proteins, the molecular machinery of life.
During the 2000's, biophysical inventions decoded all the genes in a human being. All the genes of nearly 200 different species, and some genes from more than 100,000 other species have been determined. Biophysicists analyze those genes to learn how organisms are related and how individuals differ.
Discoveries about DNA and proteins fuel progress in preventing and curing disease.
What are the applications?
Biophysics is a wellspring of innovation for our high-tech economy. The applications of biophysics depend on society's needs. In the 20th century, great progress was made in treating disease. Biophysics helped create powerful vaccines against infectious diseases. It described and controlled diseases of metabolism, such as diabetes. And biophysics provided both the tools and the understanding for treating the diseases of growth known as cancers. Today we are learning more about the biology of health and society is deeply concerned about the health of our planet. Biophysical methods are increasingly used to serve everyday needs, from forensic science to bioremediation.
Biophysics gives us medical imaging technologies including MRI, CAT scans, PET scans, and sonograms for diagnosing diseases.
It provides the life-saving treatment methods of kidney dialysis, radiation therapy, cardiac defibrillators, and pacemakers.
Biophysicists invented instruments for detecting, purifying, imaging, and manipulating chemicals and materials.
Advanced biophysical research instruments are the daily workhorses of drug development in the world's pharmaceutical and biotechnology industries. Since the 1970's, more than 1500 biotechnology companies, employing 200,000 people, have earned more than $60 billion per year.
Biophysics applies the power of physics, chemistry, and math to understanding health, preventing disease and inventing cures.
Why is biophysics important right now?
Society is facing physical and biological problems of global proportions. How will we continue to get sufficient energy? How can we feed the world's population? How do we remediate global warming? How do we preserve biological diversity? How do we secure clean and plentiful water? These are crises that require scientific insight and innovation. Biophysics provides that insight and technologies for meeting these challenges, based on the principles of physics and the mechanisms of biology.
Biophysics discovers how to modify microorganisms for biofuel (replacing gasoline and diesel fuel) and bioelectricity (replacing petroleum products and coal for producing electricity).
Biophysics discovers the biological cycles of heat, light, water, carbon, nitrogen, oxygen, heat, and organisms throughout our planet.
Biophysics harnesses microorganisms to clean our water and to produce lifesaving drugs.
Biophysics pushes back barriers that once seemed insurmountable.
Relationship Between Physicists and Biologists
There's some truth to this: advances in biology have frequently been driven more by technology than ideas about biology. For long time, many (not all, but many) answers to biological questions have been obvious once we have the technology to "just look at the thing."
As a result, you have generations of biologists with little training in math, who approach their work primarily by intuitive reasoning about their system of interest. And of course you have some very clever, amazing technologies (developed by biologists as well as physicists).
Many of the fundamental questions that can be solved by just looking at things have been solved; as a result, a lot of biological research isn't about fundamental questions – it's about details, about how something works in a different cell type or a different organism, or at a different stage of embryonic development.
The result is that there is a growing recognition that there are important, remaining fundamental questions that can be solved by getting quantitative – by having more formal, mathematical ideas about biology. We can generate mountains of data, and we can do unbelievable, nano-scale experimental manipulations that Feynman would have loved, but do we know how to think about biology instead of technology?
Some of these important questions include how the structure of regulatory networks gives rise to the network dynamics: how do regulatory networks control gene expression in space and time? How do you get irreversible transitions in cell division or development? What types of structural features produce robust biological oscillators? How do regulatory pathways evolve – either adaptively or neutrally? How can we formally describe information transduction or processing inside of a cell in a way that leads to useful insights?
And the Sun runs to its resting place. That is the decree of the Almighty, the All-Knowing. (Surah Ya Sin, 38)
The Sun has been emitting heat for around 5 billion years as a result of the constant chemical reactions taking place on its surface. At a moment determined by Allah in the future, these reactions will eventually come to an end, and the Sun will lose all its energy and finally go out. In that context, the above verse may be a reference to the Sun's energy one day coming to an end. (Allah knows the truth.)
The Arabic word "limustaqarrin" in the verse refers to a particular place or time. The word "tajree" translated as "runs," bears such meanings as "to move, to act swiftly, to move about, to flow." It appears from the meanings of the words that the Sun will continue in its course in time and space, but that this motion will continue until a specific, predetermined time. The verse "When the sun is compacted in blackness," (Surat at-Takwir, 1) which appears in descriptions of Doomsday, tells us that such a time will be coming. The specific timing is known only to Allah.
The Arabic word "taqdeeru," translated as "decree" in the verse, includes such meanings as "to appoint, to determine the destiny of something, to measure." By this expression in verse 38 of Surah Ya Sin, we are told that the life span of the Sun is limited to a specific period, one ordained by Allah. Other verses of the Qur'an on the subject read:
Allah is He Who raised up the heavens without any support – you can see that – and then established Himself firmly on the Throne. He made the Sun and Moon subservient, each running for a specified term. He directs the whole affair. He makes the Signs clear so that hopefully you will be certain about the meeting with your Lord. (Surat ar- Ra'd, 2)
He makes night merge into day and day merge into night, and He has made the Sun and Moon subservient, each one running until a specified time. That is Allah, your Lord. The Kingdom is His. Those you call on besides Him have no power over even the smallest speck. (Surah Fatir, 13)
He created the heavens and the earth with truth. He wraps the night around the day and wraps the day around the night, and has made the Sun and Moon subservient, each one running for a specified term. Is He not indeed the Almighty, the Endlessly Forgiving? (Surah az-Zumar, 5)
The use of the word "musamman" in the above verses shows that the life span of the Sun will run for a "specified term." Scientific analysis regarding the end of the Sun describes it as consuming 4 million tons of matter a second, and says that the Sun will die when that fuel has all been consumed.1 The heat and light emitted from the Sun is the energy released when matter is consumed as hydrogen nuclei turn into helium in the nuclear fusion process. The Sun's energy, and therefore its life, will thus come to an end once this fuel has been used up. (Allah knows the truth.) A report titled "The Death of the Sun" by the BBC News Science Department says:
… The Sun will gradually die. As a star's core crashes inwards, it eventually becomes hot enough to ignite another of its constituent atoms, helium. Helium atoms fuse together to form carbon. When the helium supply runs out, the centre collapses again and the atmosphere inflates. The Sun isn't massive enough to fully re-ignite its core for a third time. So it goes on expanding, shedding its atmosphere in a series of bursts… The dying core eventually forms a white dwarf – a spherical diamond the size of the Earth, made of carbon and oxygen. From this point on the Sun will gradually fade away, becoming dimmer and dimmer until its light is finally snuffed out. 2
A documentary, also called "The Death of the Sun," broadcast by National Geographic TV, provides the following description:
It (the Sun) generates heat and sustains life on our planet. But like humans, the Sun has a limited lifespan. As our star ages, it will become hotter and expand, evaporating all of our oceans and killing all life on planet Earth… The Sun will get hotter as it ages and burns fuel faster. Temperatures will increase, eventually wiping out animal life, evaporating our oceans and killing all plant life… the Sun will swell and become a red giant star, swallowing up the nearest planets. Its gravitational pull will lessen and perhaps allow Earth to escape. By the end, it will shrink into a white dwarf star, emitting a week glow for hundreds of billions of years. 3
Scientists have only recently unravelled the structure of the Sun and discovered what goes on inside it. Before that, nobody knew how the Sun obtained its energy or how it emitted heat and light. The way that such a giant mass of energy would one day consume all its energy and expire was revealed 1400 years ago in the Qur'an shows the presence of a sublime knowledge. That knowledge belongs to our Lord, Whose knowledge enfolds all things. Another verse of the Qur'an reveals:
… My Lord encompasses all things in His knowledge so will you not pay heed? (Surat Al-An'am, 80)
"By heaven furnished with paths;" (Surat adh-Dhariyat, 7)
The Arabic word "alhubuki," translated as "furnished with paths" in verse 7 of Surat adh-Dhariyat, comes from the verb "hubeke," meaning "to weave closely, to knit, to bind together." The use of this word in the verse is particularly wise and represents the current state of scientific knowledge in two aspects.
The first is this: The orbits and paths in the universe are so dense and intertwined that they constitute intersecting paths, just like the threads in a piece of fabric. The Solar System we live in is made up of the Sun, the planets and their satellites and heavenly objects in constant motion such as meteors and comets. The Solar System moves through the galaxy known as the Milky Way, which contains 400 billion stars.1 It is estimated that there are billions of galaxies. Celestial bodies and systems revolving at speeds of thousands of kilometers an hour move through space without colliding with one another.
The science of astronomy was developed with the aim of mapping the positions and courses of stars, while astro-mechanics was developed in order to determine these complex motions. Astronomers used to assume that orbits were perfectly spherical. The fact is, however, that heavenly bodies are known to follow mathematical shapes, such as spherical, elliptical, parabolic or hyperbolic orbits. Dr. Carlo Rovelli of the University of Pittsburgh says, "Our space in which we live is just this enormously complicated spin network."
Above left; the orbits of some of the bodies in the Solar System. Based on this picture and looking clockwise, it can be seen that the Solar System itself is part of even greater orbital movements.
The picture above shows some of the complex movements of stars.
The second aspect is that the description in the Qur'an of the sky using a word meaning "woven" may be a reference to the String Theory of physics. (Allah knows the truth.) According to this theory, the basic elements that comprise the universe are not point-like particles, but strings resembling miniature violin strings. These tiny, identical and one dimensional strings oscillating in the form of filaments are regarded as being like loops in appearance. It is assumed that the origin of all the diversity in the universe lies in the way these strings vibrate at different vibrations, in the same way that violin strings produce different sounds with different vibrations.
Although it is not possible to see the size of the threads in the String Theory, the only theory to bring theories such as Einstein's theory of general relativity and quantum mechanics together in a coherent way, it can still be calculated mathematically. These strings, which scientists regard as the material from which space and time are woven, are just 1.6×10-35 m (0.000000000000000000000000000000000016 meters) in size.5 This, known as Plank's length, is the smallest known, being just 10-20 of the protons that make up the nucleus of that atom.6 If an atom were to be magnified to the size of the Solar System, each one of these strings would be no bigger than a tree. 7 Bearing in mind that an atom is 100,000 times smaller than the smallest thing that can be seen with the naked eye, the minute scale of these strings can be more easily grasped.
Professor of Physics Abhay Ashtekar from the University of Pennsylvania and Professor of Physics Jerzy Lewandowski from the University of Warsaw interpret the woven appearance of space as follows in an article titled "Space and Time Beyond Einstein":
In this theory, Einstein wove the gravitational field into the very fabric of space and time… The continuum we are all used to is only an approximation. Perhaps the simplest way to visualize these ideas is to look at a piece of fabric. For all practical purposes, it represents a 2-dimensional continuum; yet it is really woven by 1-dimensional threads. The same is true of the fabric of space-time. It is only because the "quantum threads" which weave this fabric are tightly woven in the region of the universe we inhabit that we perceive a continuum. Upon intersection with a surface, each thread, or polymer excitation, endows it with a tiny "Plank quantum" of area of about 10-66 cm2. So an area of 100 cm2 has about 1068 such intersections; because the number is so huge, the intersections are very closely spaced and we have the illusion of a continuum.
An Article in the New York Times seeking an answer to the question "How Was the Universe Built?" contained the following lines:
Even the tiny quarks that make up protons, neutrons and other particles are too big to feel the bumps that may exist on the Planck scale. More recently, though, physicists have suggested that quarks and everything else are made of far tinier objects: superstrings vibrating in 10 dimensions. At the Planck level, the weave of space-time would be as apparent as when the finest Egyptian cotton is viewed under a magnifying glass, exposing the warp and woof.
In his book Three Roads to Quantum Gravity, the theoretical quantum physicist Lee Smolin devotes one chapter to "How to Weave a String" and says this on the subject:
… space may be 'woven' from a network of loops… just like a piece of cloth is 'woven' from a network of threads.
In his book Our Cosmic Habitat the cosmologist and astrophysicist Prof. Martin Rees says:
According to our present concepts, empty space is anything but simple… and on an even tinier scale, it may be a seething tangle of strings.
The way that Allah describes the universe as being woven paths and orbits in verse 7 of Surat adh-Dhariyat shows that the Qur'an is in extraordinary agreement with science. As can be seen in a great many other instances, the way that all the information revealed in the Qur'an 1400 years ago is confirmed by modern scientific data is highly thought provoking. This perfect harmony between the Qur'an and scientific developments clearly reveals that the Qur'an is the word of our Lord, the creator of and He who knows best about all things. In one verse Allah states:
"Will they not ponder the Qur'an? If it had been from other than Allah, they would have found many inconsistencies in it." (Surat an-Nisa, 82)
Some of the Scientific Miracles in Brief
Ever since the dawn of mankind, we have sought to understand nature and our place in it. In this quest for the purpose of life many people have turned to religion. Most religions are based on books claimed by their followers to be divinely inspired, without any proof. Islam is different because it is based upon reason and proof.
There are clear signs that the book of Islam, the Quran, is the word of God and we have many reasons to support this claim:
· There are scientific and historical facts found in the Quran which were unknown to the people at the time, and have only been discovered recently by contemporary science.
· The Quran is in a unique style of language that cannot be replicated, this is known as the 'Inimitability of the Quran.'
· There are prophecies made in the Quran and by the Prophet Muhammad, may the mercy and blessings of God be upon him, which have come to be pass.
This article lays out and explains the scientific facts that are found in the Quran, centuries before they were 'discovered' in contemporary science. It is important to note that the Quran is not a book of science but a book of 'signs'. These signs are there for people to recognise God's existence and affirm His revelation. As we know, science sometimes takes a 'U-turn' where what once scientifically correct is false a few years later. In this article only established scientific facts are considered, not just theories or hypothesis.
Scientific Facts in the Quran
The Quran was revealed to the Prophet Muhammad in the 7th century.
Science at the time was primitive, there were no telescopes, microscopes or anything even close to the technology we have today. People believed that the sun orbited the earth and that the sky was held up by big pillars at the corners of a flat earth. Within this backdrop the Quran was revealed, and it contains many scientific facts on topics ranging from astronomy to biology, geology to sociology.
Some people may claim that the Quran was changed as new scientific facts were discovered but this cannot be the case because it is a historically documented fact that the Quran is preserved in its original language. The Quran was written down and memorised by people during the lifetime of the Prophet Muhammad. One of the copies of the Quran which was written a few years after the death of the Prophet Muhammad is preserved in a museum in Uzbekistan. This copy is over 1400 years old and is exactly the same as the Arabic Quran that we have today.
The following are nine scientific facts found in the Quran:
1. Origin of Life
Water is essential for all living things. We all know that water is vital to life but the Quran makes a very unusual claim:
We made every living thing from water? Will they not believe? (Quran 21:30)
In this verse water is pointed out as the origin of all life. All living things are made of cells. We now know that cells are mostly made up of water. For example, 80% of the cytoplasm (basic cell material) of a standard animal cell is described as water in biology textbooks.
The fact that living things consist mostly of water was discovered only after the invention of the microscope. In the deserts of Arabia, the last thing someone would have guessed is that all life came from water.
2. Iron
Iron is not natural to the earth. It did not form on the earth but came down to earth from outer space. This may sound strange but it's true. Scientists have found that billions of years ago the earth was stuck by meteorites. These meteorites were carrying Iron from distant stars which had exploded.
The Quran says the following on the origin of Iron:
"We sent down Iron with its great inherent strength and its many benefits for humankind." (Quran 57:25)
God uses the words 'sent down' for Iron. It is clear from the verse that Iron is not an earthly material, but was sent down for the benefit of humanity. The fact that Iron came down to earth from outer space is something which could not be known by the primitive science of the 7th century.
3. Sky's Protection
The sky plays a crucial role in protecting the earth. The sky protects the earth from the lethal rays of the sun. If the sky did not exist then the sun's radiation would have killed off all life on earth. It also acts like a blanket wrapped around the earth, to protect it from the freezing cold of space. The temperature just above the sky is approximately -270oC. If this temperature was to reach earth then the planet would freeze over instantly. The sky also protects life on earth by warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night. These are some of the many protective functions of the sky.
The Quran asks us to consider the sky in the following verse:
"We made the sky a protective ceiling. And yet they are turning away from Our signs!" (Quran 21:32)
The Quran points to the sky's protection as a sign of God. The protective properties of the sky were discovered by scientific research conducted in the 20th century.
4. Mountains
The Quran draws our attention to a very important characteristic of mountains:
"Did We not make the earth a resting place? And the mountains as stakes?" (Quran 78:6-7)
The Quran indicates that mountains have deep roots by using the word stakes to describe them. In fact mountains do have deep roots, and the word stakes is an accurate description for them. A book titled 'Earth' by Geophysicist Frank Press explains that mountains are like stakes, and are buried deep under the surface of the earth. Mount Everest (pictured below), the height of which is approximately 9 km above ground, has a root deeper than 125 km.
The fact that mountains have deep 'stake' like roots was not known, until after the development of the theory of plate tectonics in the beginning of the 20th century.
5. Expansion of the Universe
At a time when the science of Astronomy was still primitive, the expansion of the universe was described in Quran:
"And it is We who have built the Universe with [Our creative] power and keep expanding it." (Quran 51:47)
The fact that the universe is expanding was discovered in the last century. The physicist Stephen Hawking in his book 'A Brief History of Time' writes, "The discovery that the universe is expanding was one of the great intellectual revolutions of the 20th century.".
The Quran mentioned the expansion of the universe even before the invention of the telescope!
6. Sun's Orbit
In 1512 the astronomer Nicholas Copernicus put forward his theory that the Sun is motionless at the centre of the solar system, and that the planets revolve around it. The belief that the Sun is stationary was widespread amongst astronomers until the 20th century. It is now a well-established scientific fact that the Sun is not stationary, but is moving in an orbit around the centre of our Milky Way galaxy[7].
The Quran mentions the orbit of the Sun:
"It is He who created night and day, the Sun and the Moon, each floating in its orbit." (Quran 21:33)
The Quran would have been wrong according to astronomers just a couple of decades ago. But we now know that the Quranic account of the Sun's motion is consistent with modern Astronomy.
7. The Ocean
The Quran uses imagery to covey its deep meanings, here it describes the state of the unbelievers as:
"Darkness out in a deep ocean which is covered by waves, above which are waves, above which are clouds, layers of darkness, one upon the other. When one puts out his hand [therein], he can hardly see it. Those God gives no light to, they have no light." (Quran 24:40)
It is commonly thought that waves only occur on the surface of the ocean. However oceanographers have discovered that there are internal waves that take place below the surface of the ocean. These waves are invisible to the human eye, and can only be detected by specialist equipment. The Quran mentions darkness in a deep ocean above which are waves, above which are waves, then clouds above that. This description is not only remarkable because it describes the internal waves in the ocean, but also because it describes darkness deep in the ocean. A human being can dive no more than 70 metres without breathing equipment. Light is present at that depth, but if we go down 1000 metres it is completely dark. 1400 years ago there were no submarines or specialist equipment to discover internal waves or the darkness deep inside the oceans.
8. Lying and Movement
There was a cruel oppressive tribal leader named Abu Jahl who lived during the time of Prophet Muhammad, may the mercy and blessings of God be upon him. God revealed a verse of the Quran to warn him:
"No Indeed! If he does not stop, We will seize him by the forehead, his lying, sinful forehead." (Quran 96:15-16)
God does not call this person a liar, but calls his forehead (the front part of the brain) 'lying' and 'sinful', and warns him to stop.
This verse is significant for two reasons. The first is that the front part of our brain is responsible for voluntary movement.This is known as the frontal lobe. A book titled 'Essentials of Anatomy and Physiology' which includes the results of research on the functions of this area states: The motivation and the foresight to plan and initiate movements occur in the anterior portion of the frontal lobes, the prefrontal area. The part of the brain that is responsible for movement is said to be seized if the man does not stop.
Secondly, numerous studies have shown that this same region (frontal lobe) is responsible for the lying function of the brain. One such study at the University of Pennsylvania in which volunteers were asked questions during a computerized interrogation, it was found that when the volunteers were lying there was significantly increased activity in the prefrontal and premotor cortices (frontal lobe region).
The front part of the brain is responsible for movement and lying. The Quran links movement and lying to this area. These functions of the frontal lobe were discovered with medical imaging equipment which was developed in the 20th century.
9. Pain Receptors
For a long time it was thought that the sense of feeling and pain was dependent on the brain. However it has been discovered that there are pain receptors present in the skin[14]. Without these pain receptors, a person would not be able to feel pain.
Consider the following verse on pain:
"We shall send those who reject Our revelations to the (Hell) Fire. When their skins have been burned away, We shall replace them with new ones so that they may continue to feel the pain: God is Almighty, All-Wise." (Quran 4:56)
God tells the people who reject his message that when they are in Hell and their skins are burnt off (so they can't feel any pain), he will give them new skins so that they continue to feel the pain.
The Quran makes it clear that pain is dependent upon on the skin. The discovery of pain receptors in the skin is a fairly recent discovery for Biology.
These are just some of the many scientific facts found in the Quran. It is important to note that the Quran is not a book of science, but that it is consistent with science. To claim that scientific facts in the Quran are due to coincidence would be irrational. The best explanation is that God revealed this knowledge to the Prophet Muhammad.
Just like the Quran contains knowledge about the natural world, it also contains information about the inner dimensions of our souls. It relates to our feelings, wants and needs. The Quran informs us that we have a purpose in life, and that following God's guidance will lead us to inner peace in this life, and Paradise in the hereafter. And that rejection of his message will lead to depression in this life and Hellfire after death.
"We shall show them Our signs in the Universe and within themselves, until it becomes clear to them that this is the Truth. Is it not enough that your Lord is the witness of all things?" (Quran 41:53)
The Miracle of Iron
Iron is one of the elements highlighted in the Quran. In the chapter known Al-Hadeed, meaning Iron, we are informed:
"And We also sent down iron in which there lies great force and which has many uses for mankind…" (Quran 57:25)
The word "anzalna," translated as "sent down" and used for iron in the verse, could be thought of having a metaphorical meaning to explain that iron has been given to benefit people. But, when we take into consideration the literal meaning of the word, which is, "being physically sent down from the sky, as this word usage had not been employed in the Quran except literally, like the descending of the rain or revelation, we realize that this verse implies a very significant scientific miracle. Because, modern astronomical findings have disclosed that the iron found in our world has come from giant stars in outer space.[1]
Not only the iron on earth, but also the iron in the entire Solar System, comes from outer space, since the temperature in the Sun is inadequate for the formation of iron. The sun has a surface temperature of 6,000 degrees Celsius, and a core temperature of approximately 20 million degrees. Iron can only be produced in much larger stars than the Sun, where the temperature reaches a few hundred million degrees. When the amount of iron exceeds a certain level in a star, the star can no longer accommodate it, and it eventually explodes in what is called a "nova" or a "supernova." These explosions make it possible for iron to be given off into space.
One scientific source provides the following information on this subject:
"There is also evidence for older supernova events: Enhanced levels of iron-60 in deep-sea sediments have been interpreted as indications that a supernova explosion occurred within 90 light-years of the sun about 5 million years ago. Iron-60 is a radioactive isotope of iron, formed in supernova explosions, which decays with a half life of 1.5 million years. An enhanced presence of this isotope in a geologic layer indicates the recent nucleosynthesis of elements nearby in space and their subsequent transport to the earth (perhaps as part of dust grains)."
All this shows that iron did not form on the Earth, but was carried from Supernovas, and was "sent down," as stated in the verse. It is clear that this fact could not have been known in the 7th century, when the Quran was revealed. Nevertheless, this fact is related in the Quran, the Word of God, Who encompasses all things in His infinite knowledge.
The fact that the verse specifically mentions iron is quite astounding, considering that these discoveries were made at the end of the 20th century. In his book Nature's Destiny, the well-known microbiologist Michael Denton emphasizes the importance of iron:
"Of all the metals there is none more essential to life than iron. It is the accumulation of iron in the center of a star which triggers a supernova explosion and the subsequent scattering of the vital atoms of life throughout the cosmos. It was the drawing by gravity of iron atoms to the center of the primeval earth that generated the heat which caused the initial chemical differentiation of the earth, the outgassing of the early atmosphere, and ultimately the formation of the hydrosphere. It is molten iron in the center of the earth which, acting like a gigantic dynamo, generates the earth's magnetic field, which in turn creates the Van Allen radiation belts that shield the earth's surface from destructive high-energy-penetrating cosmic radiation and preserve the crucial ozone layer from cosmic ray destruction…
"Without the iron atom, there would be no carbon-based life in the cosmos; no supernovae, no heating of the primitive earth, no atmosphere or hydrosphere. There would be no protective magnetic field, no Van Allen radiation belts, no ozone layer, no metal to make hemoglobin [in human blood], no metal to tame the reactivity of oxygen, and no oxidative metabolism.
"The intriguing and intimate relationship between life and iron, between the red color of blood and the dying of some distant star, not only indicates the relevance of metals to biology but also the biocentricity of the cosmos…"
This account clearly indicates the importance of the iron atom. The fact that particular attention is drawn to iron in the Quran also emphasizes the importance of the element.
Moreover, iron oxide particles were used in a cancer treatment in recent months and positive developments were observed. A team led by Dr. Andreas Jordan, at the world famous Charité Hospital in Germany, succeeded in destroying cancer cells with this new technique developed for the treatment of cancer—magnetic fluid hyperthermia (high temperature magnetic liquid). As a result of this technique, first performed on the 26-year-old Nikolaus H., no new cancer cells were observed in the patient in the following three months.
This method of treatment can be summarized as follows:
1. A liquid containing iron oxide particles is injected into the tumour by means of a special syringe. These particles spread throughout the tumour cells. This liquid consists of thousands of millions of particles, 1,000 times smaller than the red blood corpuscles, of iron oxide in 1 cm3 that can easily flow through all blood vessels.
2. The patient is then placed in a machine with a powerful magnetic field.
3. This magnetic field, applied externally, begins to set the iron particles in the tumour in motion. During this time the temperature in the tumour containing the iron oxide particles rises by up to 45 degrees.
4. In a few minutes the cancer cells, unable to protect themselves from the heat, are either weakened or destroyed. The tumour may then be completely eradicated with subsequent chemotherapy.
In this treatment it is only the cancer cells that are affected by the magnetic field, since only they contain the iron oxide particles. The spread of this technique is a major development in the treatment of this potentially lethal disease. Iron has also been found to be a cure for people suffering from anemia. In the treatment of such a widespread diseases, the use of the expression "iron in which there lies great force and which has many uses for mankind" (Quran, 57:25) in the Quran is particularly noteworthy. Indeed, in that verse, the Quran may be indicating the benefits of iron even for human health. (God knows best.)
The Quran on Seas and Rivers
Modern Science has discovered that in the places where two different seas meet, there is a barrier between them. This barrier divides the two seas so that each sea has its own temperature, salinity, and density. For example, Mediterranean sea water is warm, saline, and less dense, compared to Atlantic ocean water. When Mediterranean sea water enters the Atlantic over the Gibraltar sill, it moves several hundred kilometers into the Atlantic at a depth of about 1000 meters with its own warm, saline, and less dense characteristics. The Mediterranean water stabilizes at this depth (see figure 1).
Although there are large waves, strong currents, and tides in these seas, they do not mix or transgress this barrier.
The Holy Quran mentioned that there is a barrier between two seas that meet and that they do not transgress. God has said:
"He has set free the two seas meeting together. There is a barrier between them. They do not transgress." (Quran 55:19-20)
But when the Quran speaks about the divider between fresh and salt water, it mentions the existence of "a forbidding partition" with the barrier. God has said in the Quran:
"He is the one who has set free the two kinds of water, one sweet and palatable, and the other salty and bitter. And He has made between them a barrier and a forbidding partition." (Quran 25:53)
One may ask, why did the Quran mention the partition when speaking about the divider between fresh and salt water, but did not mention it when speaking about the divider between the two seas?
Modern science has discovered that in estuaries, where fresh (sweet) and salt water meet, the situation is somewhat different from what is found in places where two seas meet. It has been discovered that what distinguishes fresh water from salt water in estuaries is a "pycnocline zone with a marked density discontinuity separating the two layers." This partition (zone of separation) has a different salinity from the fresh water and from the salt water(see figure 2).
This information has been discovered only recently, using advanced equipment to measure temperature, salinity, density, oxygen dissolubility, etc. The human eye cannot see the difference between the two seas that meet, rather the two seas appear to us as one homogeneous sea. Likewise, the human eye cannot see the division of water in estuaries into the three kinds: fresh water, salt water, and the partition (zone of separation).
The Quran on Mountains
A book entitled Earth is a basic reference textbook in many universities around the world. One of its two authors is Professor Emeritus Frank Press. He was the Science Advisor to former US President Jimmy Carter, and for 12 years was the President of the National Academy of Sciences, Washington, DC. His book says that mountains have underlying roots.These roots are deeply embedded in the ground, thus, mountains have a shape like a peg (see figures 1, 2, and 3).
Figure 1: Mountains have deep roots under the surface of the ground. (Earth, Press and Siever, p. 413.)
Figure 2: Schematic section. The mountains, like pegs, have deep roots embedded in the ground. (Anatomy of the Earth, Cailleux, p. 220.)
Figure 3: Another illustration shows how the mountains are peg-like in shape, due to their deep roots. (Earth Science, Tarbuck and Lutgens, p. 158.)
This is how the Quran has described mountains. God has said in the Quran:
"Have We not made the earth as a bed, and the mountains as pegs?" (Quran 78:6-7)
Modern earth sciences have proven that mountains have deep roots under the surface of the ground (see figure 3) and that these roots can reach several times their elevations above the surface of the ground.So the most suitable word to describe mountains on the basis of this information is the word 'peg,' since most of a properly set peg is hidden under the surface of the ground. The history of science tells us that the theory of mountains having deep roots was introduced only in the latter half of the nineteenth century.
Mountains also play an important role in stabilizing the crust of the earth.They hinder the shaking of the earth. God has said in the Quran:
"And He has set firm mountains in the earth so that it would not shake with you…" (Quran 16:15)
Likewise, the modern theory of plate tectonics holds that mountains work as stabilizers for the earth. This knowledge about the role of mountains as stabilizers for the earth has just begun to be understood in the framework of plate tectonics since the late 1960's.
Could anyone during the time of the Prophet Muhammad have known of the true shape of mountains? Could anyone imagine that the solid massive mountain which he sees before him actually extends deep into the earth and has a root, as scientists assert? A large number of books of geology, when discussing mountains, only describe that part which is above the surface of the earth. This is because these books were not written by specialists in geology. However, modern geology has confirmed the truth of the Quranic verses.
Science and Miracles (1998) Theodore M. Drange
1. The definition of "Miracle"
The problem I wish to investigate is the relation between science and religion, with a special focus on religion's appeal to miracles. Let us define a "miracle" simply as an event which violates at least one law of nature. I realize that the term is used in other ways. For example, it is sometimes additionally required that miracles be caused by a supernatural being. For our purposes and in the interest of economy, that further requirement can be dispensed with. Alternatively, a miracle is sometimes taken to be any extraordinary event, particularly one that provides someone with a great benefit. That is certainly another use of the term in English, but not relevant to our topic, so let us disregard it. If we employ the definition initially given, that will allow us to focus on a particularly troublesome puzzle in the philosophy of science.
If miracles violate laws of nature, then they could never be explained by appeal to natural law. Note that it needs to be a genuine law of nature that is violated by a miracle, not a manmade generalization erroneously taken as a law of nature. This needs some clarification. By a law of nature I mean a proposition which describes an actual uniformity that obtains in our universe. An example would be the Archimedean Law that a floating body always displaces an amount of fluid the weight of which is equal to its own weight. And an example of a miracle which violates that law would be a man walking on water (thereby displacing an amount of fluid the weight of which would be considerably less than his own bodyweight). In science, events are explained naturalistically (i.e., by appeal to laws of nature), so a miracle would be an event that could never be explained in that way. But if events which cannot at present be explained in that way were to come to be explained naturalistically in the future, then, in retrospect, it would need to be said of them that they were never miracles, although they may at one time have (erroneously) been thought to be that. At the very least, the laws that miracles violate need to be genuine ones.
Consider an example. Centuries ago, it was regarded a law of nature that matter cannot be destroyed. Thus, an event like an atomic explosion, in which matter is destroyed, would at that time have been considered a miracle, for it violates the given law. But subsequent science came to abandon or amend the law in question in such a way that atomic explosions no longer violate natural law. A miracle, then, must be regarded, not as an event which violates current law (which may very well come to be superseded), but an event which violates one or more genuine laws, i.e., ones which can never be superseded by laws of nature which are more accurate and which cohere better with other parts of science.
What would be the status of laws of nature if miracles were actually to occur? First, would they cease to be genuine laws? If we say that a generalization that is violated by some event cannot be a genuine law of nature, then it would follow that miracles are logically impossible. That can be shown as follows:
(1) Miracles, by definition, are events which violate genuine laws of nature.
(2) If a generalization is violated by an event, then it cannot be a genuine law of nature.
(3) Thus, it is impossible for a genuine law of nature to be violated by any event. [from (2)]
(4) Hence, it is impossible for any event to be a miracle. [from (1) & (3)]
I think what we need to do here, to generate our philosophical issue, is to allow that it is at least logically possible for a law of nature to be violated. Let us therefore understand the concept of a law of nature in such a way that step (2) of the above proof is false. It may be that no laws of nature are ever violated, but there is no contradiction in the mere idea of it.
Another issue is that of truth. If a law of nature were to be violated, then could it still be true? One answer that might be given is: Yes, a violated law could still be true because laws of nature are only intended to describe events within the natural realm and miracles are outside the natural realm. Thus, miracles would not then render laws of nature false, for they would not show that the laws fail to correctly describe the natural realm. However, to view the matter in this way, the definition of "miracle" would need to be changed slightly. Instead of saying that miracles violate laws of nature, we would need to say that miracles are outside the natural realm and would violate laws of nature if they were in the natural realm. They would then not actually violate laws of nature, since laws of nature only describe events within the natural realm.
I do not like this way of viewing matters, because it places too much emphasis on the concept of a "natural realm." To work with a definition of "miracles" as events outside the natural realm, we would need some criterion for deciding whether or not an event is inside or outside that realm, and we do not have any such criterion. The result would be that the term "miracle" would be obscure, perhaps even meaningless. Let us, therefore, simply go with our original definition of a miracle as an event which violates a law of nature. That results in the conclusion that if an miracle were to occur, then the law of nature which it violates would be false, since such a law would be a generalization with at least one exception to it. Thus, some laws would be false (namely, the ones violated by miracles) and other laws would be true (namely, those not violated by any miracles). This way of speaking, distinguishing true laws of nature from false ones, may sound rather peculiar, but there seems to be no other meaningful way to permit talk of miracles to enter the discussion. The idea of a law still being useful even though it is false is a familiar one. Newton's Laws, for example, have been superseded in contemporary physics (and thus regarded as false), and yet they are still used in various practical fields. So, to speak of a law as false is not incoherent.
However, there is a problem here. Previously, a distinction was drawn between "genuine laws" and "erroneous (or superseded) laws." How could that distinction still be drawn if we allow that even some of the genuine laws might be false? Let us say that if genuine laws are false, it is only because of isolated counter-instances which cannot be explained or predicted on the basis of any other empirical laws. But when erroneous (or superseded) laws are false, it is because of regular counter-instances which are both explainable and predictable on the basis of other empirical laws. Atomic explosions, for example, occur according to known regularities on the basis of which they could be explained and predicted. Thus, the law that matter cannot be destroyed is an erroneous (or superseded) one. But if a man were to walk on water, although that would make Archimedes' Law false, it would not make it an erroneous law in the given sense. The counter-instance(s) would still be isolated and neither explainable nor predictable on the basis of any other empirical laws. Archimedes' Law could still be a genuine law, though it would no doubt be somewhat suspect under such circumstances.
What would be the result if people walking on water were to become commonplace? Suppose various men were to do it every year, say, on Easter Sunday. Their action could not be explained by Archimedes' Law, since the amount of fluid they displace as they walk on water does not correspond to a force sufficient to keep them from sinking. Some other force would be sought, but suppose that none is ever found and so their actions remain a mystery for science forever. Although such counter-instances to Archimedes' Law would in that case not be isolated events, they would still be miracles if, indeed, the law cannot be replaced by other natural laws which are not violated by the given events. Thus, miracles need not be isolated events, but they do need to be events that violate natural law which are forever unexplainable within the system of science.
2. Scientists' Attitudes
The philosophical issue which now comes into play is that of the relation between science and miracles (defined in the given way), particularly the attitude of scientists towards miracles. There seem to be at least the following possibilities:
(A) No scientist could ever believe in miracles under any circumstances.
(B) Scientists could believe in miracles, but not as scientists.
(C) Scientists could believe in miracles, even as scientists, but not when they are engaged in scientific research on the specific area in which the alleged miracles occur.
(D) Scientists, as scientists, could believe in miracles, even when engaged in scientific research on the specific area in which the alleged miracles occur, but such belief could not be regarded to be a result of the research or a scientific finding.
It seems clear that position (A) is incorrect, for there certainly have been scientists in the past who believed in miracles and there are still scientists today who do so (for example, many of those who identify themselves as Christians). But even if (A) is deleted, the question of which of the other positions is the correct one is rather difficult.
Certainly the last part of position (D) is correct. It could never be a scientific finding that a miracle occurred, for science is the attempt to understand reality in terms of the laws of nature. To say that a miracle occurred is to abandon the scientific (= naturalistic) perspective on the matter. If a scientist were to end up with such a belief, then it would be incompatible with the scientific point of view. It would be as if to say, "Here is something that could never be naturalistically explained and so it lies outside the domain of science."
It might be objected here that the purpose of science is not to try to understand reality but only to predict it and thereby control it. That is, science is of significance only to the extent that it yields (or has the prospect of yielding) technological results. This is the pragmatic view of the nature of science. I don't particularly care for it, since I find it too limited, but even if it were correct, it would still leave no room for any appeal to miracles within science. There is no way that an appeal to miracles could lead to theories which produce predictions or technological results. Thus, whether science is construed realistically or pragmatically, all appeals to miracles would be excluded from it.
But even if the last part of position (D), above, is correct, the first part of it may not be. It could be, instead, that (B) or (C) is the correct approach to take on this matter. Let us consider a hypothetical situation. Suppose a man is diagnosed with a terminal illness but then recovers fully. Such events have been known to happen and they are often termed "miracles." Some medical researchers believe that miracles, of that sort, do indeed occur. One main question is whether, when they express such belief, they can do so as scientists, or whether they necessarily do so only as laypersons (or private citizens, as it is sometimes put).
According to position (D), it is indeed possible for medical researchers to believe, as scientists, that a miraculous cure has occurred. It is simply that they cannot put this down as a "scientific finding." But it might be objected that if they cannot put the result down as a "scientific finding," then when they claim that a miracle has occurred, they are not speaking as scientists at all. In order to speak as a scientist, one must be in a position to report a scientific finding, for the reporting of such findings is a major component of science. The first part of (D), therefore, conflicts with its last part, and so (D) needs to be rejected.
According to position (C), it would be possible for other scientists to claim, as scientists, that a miraculous cure has occurred, but not those scientists (medical researchers) who are engaged in the specific area of research in question. But that seems rather anomalous. Why should scientists who are outside a particular field be in any better position to speak in the name of science on a matter related to that field than those scientists who are working in the very field in question? It would seem more reasonable to say that the people best able to speak in the name of science on a particular area would be the very scientists who are working in that area. Position (C) has other difficulties as well, but this one seems sufficient to refute it.
By a process of elimination, only position (B) remains, and that is the one which I shall endorse. Scientists can claim that miracles occur, but when they do so, they do so only as laypersons, not as scientists. But what, then, are we to say about such persons? Their minds seem to be compartmentalized into at least a scientific part and a religious part. When they think in terms of their profession, they have a positive outlook on science, assuming that what it deals with is in principle explainable by appeal to natural law, but when they think religiously, they have a negative outlook on science, assuming that there are aspects of reality that can never be explained by appeal to natural law, no matter how far science advances.
Why would anyone assume that science has such limits? What possible evidence could there be that there are events which science will be forever unable to explain? The only possible evidence is that certain events have not as yet been given naturalistic explanations. However, many such events in the past later came to be explained naturalistically. Thus, the mere use of induction should lead us to infer that, eventually, the events presently unexplained may very well, and perhaps even probably will, be explained. It would seem, then, that the epistemic stance most compatible with a scientific way of thinking would be to withhold judgement on whatever events have not as yet been explained naturalistically. To reason that what has not as yet been explained can never be explained would be invalid. It would be a non sequitur (more specifically, a kind of hasty generalization). Furthermore, one should not adopt a pessimistic outlook on science by calling such events "miraculous," for to do so would be not only unscientific, but anti-scientific as well.
Two points should be made regarding this matter. First, if there are scientists who have such a pessimistic (anti-scientific) outlook with regard to their own profession, then presumably they acquired it from religion, which partly regulates the early mental development of most children. There is certainly no scientific basis whatever for such pessimism. And, second, it may be that the belief in miracles is connected with the idea that there are aspects of reality which must be forever beyond scientific scrutiny. If one already believes that there are facts which it is impossible for science to explain, then one would be already predisposed towards a belief in miracles. Well, what sorts of facts might those be? Here are some possible candidates:
(A) Religious experiences in people
(B) Selfless love and sacrifice
(C) Objective values (e.g., morality)
(D) God and an afterlife
(E) Free will
(F) Mind or consciousness
(G) Life
(H) Basic uniformities of nature
(I) The fact that the uniformities permit life
(J) Laws of logic
(K) Abstract entities, like numbers
(L) The existence of the universe itself
(M) The fact that something exists
In each case, there are two questions: whether there is some fact there to be explained, and, if so, whether there is any hope that science might come up with a complete and adequate explanation of that fact. If, for some items on the list, the answers are "yes" and "no," respectively, then that would predispose one towards a belief in miracles. That is, if there are other facts to be explained which science can't possibly explain, then there is not so much involved in adding (the occurrence of) miracles to the list. I think that many of the items listed above are ones which religion appeals to as "facts beyond scientific explanation." At any rate, if one is indoctrinated by religion to believe that there are such facts, then the acceptance of miracles would come easily. If the person should later adopt science as a profession, then the kind of compartmentalization of the person's mind mentioned above would be an expected outcome.
It is an interesting question whether any items on the above list really have the features claimed for it by religion, that is: (1) a fact to be explained, and (2) forever incapable of any naturalistic explanation. I myself am inclined to deny it. For some of the items, it is condition (1) that fails to be met. I would say that of (C), (D), (J), (K), & (M). For all the other items, it is condition (2) that fails to be met: i.e., naturalistic explanations can be given. I shall not defend this here, for it is a large topic and beyond the scope of the present essay.
Perhaps the main question before us at this point is whether, within such mental compartmentalization as described above, the person necessarily holds incompatible beliefs. What it comes down to is the issue whether the scientist qua scientist must believe that all of reality is naturalistically explainable. If so, then scientists who believe in miracles would be inconsistent in their thinking.
We have already established that the scientist qua scientist cannot believe in miracles. But it is a further question whether he must deny that they ever occur. In other words, is the scientist qua scientist like an agnostic regarding miracles, neither believing in them nor denying them, or is he like an atheist, denying that they ever occur? If he is like an atheist, then for him to believe in miracles in some other compartment of his mind would be inconsistent, for it would contradict something that he believes in the scientific compartment. But if he is only like an agnostic, then there need be no such inconsistency. In his scientific compartment, there would (necessarily) be no belief in miracles, but there would not be anything that contradicts their occurrence either.
So, what is the answer? I argued above that when people work as scientists, they necessarily have a naturalistic worldview. But do they, in addition, necessarily believe that such a worldview is complete and not contradicted by anything else in reality? There are indeed scientists who do not regard the naturalistic worldview to be complete in that way. In their scientific work, they are only methodological naturalists and not also metaphysical naturalists. That is, they assume naturalism as an outlook presupposed by their scientific work, but they do not regard naturalism to be generally true of all reality. They might say, "I can make no reference to miracles here in science, but science is limited; there are aspects of reality that lie beyond it." Are such scientists necessarily deficient as scientists? I shall make no pronouncement on this matter here but will leave it open. Certainly scientists who believe in miracles have compartmentalized minds, and some of the time (in their religious life) they have not only an unscientific but an anti-scientific outlook. But whether they must also have inconsistent beliefs is a further matter, one which I shall leave to the reader to judge.
Crystallography: Exploring the Structure of Matter
Crystallography is the study of atomic and molecular structure. Crystallographers want to know how the atoms in a material are arranged in order to understand the relationship between atomic structure and properties of these materials. They work in many disciplines, including chemistry, geology, biology, materials science, metallurgy and physics. Crystallographers study diverse substances, from living cells to superconductors, from protein molecules to ceramics.
Crystallography began with the study of crystals, like quartz. Today, crystallographers study the atomic architecture of any material that can form an orderly solid – from diamonds to viruses. They also investigate a wide variety of other materials, such as amorphous thin films, membranes, liquid crystals, fibers, glasses, liquids, gases and quasicrystals.
Because many crystallographers use x-rays to study crystals, the field is often called "x-ray crystallography." But modern crystallographers use many other methods as well. Atomic force microscopy, neutron diffraction, electron crystallography, molecular modeling, high- and low-temperature studies, high-pressure diffraction and micro-gravity experiments in space are all methods used by crystallographers to unlock the secrets of structure and function.
Crystallographers at Work
Two familiar materials, diamond and graphite, provide an easy example of how the arrangement of atoms determines the characteristics of a material. Both diamonds and graphite are composed entirely of carbon atoms. A diamond is one huge molecule, very hard, with a very high melting point. By contrast, the carbon atoms in graphite are arranged in layers of flat hexagons which can slide relative to each other, so graphite is the soft, greasy material used in pencils and lubricants. Excitement was high when scientists recently discovered a new all-carbon chemical, with each molecule consisting of sixty carbon atoms. The crystal structure of "C60", shown here1 looks like a geodesic dome or soccer ball. Scientists are enthusiastically investigating the unusual electrical, magnetic and chemical properties of these tiny soccer balls.
The three-dimensional shape of a molecule relates to how the molecule will work – in a chemical reaction in the laboratory, or in a cell in your body. Once the relationship between the structure and properties is understood, it is often possible to design new materials, such as plastic, drugs, alloys, and superconductors, which have specific desired properties. For instance, crystallographers found that, in its crystal form, coenzyme B12 has a very long chemical bond (on a molecular scale) between the central cobalt and the carbon atom. This located a weak, reactive part of the molecule, where a free radical reaction is initiated when the bond breaks. (2) With this knowledge, other scientists may be able to develop new catalysts to speed up the chemical reaction.
A precise fit between two molecules is often the requirement for a reaction. Crystallographers have recently discovered how proteins recognize the shape of DNA to turn genes on and off. (3) With information like this, other scientists may design drugs to control blood pressure, inhibit the growth of the AIDS virus, or cure the common cold.
Image 2: Crystal structure of a protein which regulates DNA. Two gray helical ribbons represent the DNA; cylinders outline the protein ÿ-helices; the dark lines show bonds between atoms in an important part of the protein which makes specific contacts to the DNA.
Liquid crystals are sometimes described as the "fourth state of matter." The molecules in liquid crystals are arranged in an orderly, periodic way, but these materials are fluid, like a liquid. Using diffraction techniques, polarizing microscopy and/or nuclear magnetic resonance (NMR), crystallographers can determine the approximate arrangement of molecules in liquid crystals. They have also studied transitions between liquid crystalline phases in real time using synchrotron x-ray sources. There is still a great deal that we do not understand about these novel materials.
Image 3: A schematic cartoon showing one possible arrangement of molecules in a liquid crystal. Ovals represent the polar head group and "tails" the hydrocarbon chain. (4)
Quasicrystals are crystals with quasi-periodic order. They might also be described as impossible crystals. The molecules in some quasicrystals are arranged about an axis of 5-fold symmetry. Traditionally, crystallographers have considered this to be impossible since there is no strictly periodic way to make this arrangement work. (Try covering your floor with tiles shaped like regular pentagons. Your pattern will show gaps or overlaps!) Nevertheless, there are crystals that have 5 fold external symmetry and display 5-fold (or 10-fold) diffraction symmetry (when x-rays are passed through them). These structures pose a great challenge to crystallographers.
In chemistry, biology and materials science – anywhere atomic structure is the key to understanding and controlling chemical and physical properties – crystallographers are making fundamental discoveries and exciting advances.
Brain and Senses
Your brain is the most complex part of your body, it performs a large number of amazing calculations every second, taking in information from the outside world in the form of senses and allowing you to quickly respond to various situations. Use this senses lesson plan to show students some fun brain activities and teach them more about brain functions such as memory, taste, sight and touch.
It is said that as far back as 10000 years ago people had a strong awareness of the importance of the head and brain.
- The word 'brain' originated from the ancient Egyptians.
- Early philosophers such as Socrates and Aristotle wrote and made theories regarding the human brain although Aristotle also believed that the heart played a crucial role in human intelligence.
- The human brain interprets the world around us in many different ways. These processes are researched in the study of neuroscience.
- Can you name some of the ways that humans process information from the world around us? Memory, reflexes, senses etc.
- If you have access to old human and animal skulls they are great for giving a physical perspective. Ask the students for any differences or similarities they notice between them. Good posters and images are also useful, you explain what scientists already know about the human skull and brain.
Physical differences in the brain of different species go much deeper than the obvious size and shape aspects, feel free to discuss more about this, the senses and brain functions in general.
Sight Activity:
- Another way that our brains make assumptions is through optical illusions. Our brain tries to fill in the gaps, especially as we have been taught to use specific shapes and angles to tell us about size. Your brain is always looking for blank spaces and filling them with information. Our brains are always trying to recognise things in our environment and create meaning out of them. It is part of our survival instinct. Sometimes your brain leaps to the wrong conclusion and you get a surprise. Magicians and illusionists are experts at using this to their advantage.
Taste Activity:
- Show the students a colored jellybean, red for example. They have to guess what flavour it might be. After they have guessed, give them all one of these jellybeans and see if they were right. Talk to them about how our brain sometimes makes assumptions about certain things that we have a memory of.
Memory Activity:
- Test the short term memory of the students. Show them a number of different objects and tell them to remember as many as possible. They have only one minute to look at them. Hide the objects after one minute has passed. Let the kids write down as many things as they can remember on a sheet of paper. Can they remember all of the items? Are there any that were forgotten by everyone? What could they do to improve their memory?
Touch Activity:
What areas of our bodies are most sensitive to touch? Our Hands? Feet? Fingers?
- Bend a paper clip into the shape of a U with the tips about 2 cm apart. Make sure the tips of the U are evenly aligned with each other.
- Lightly touch the two ends of the paper clip on the back of your partners hand. Your partner should not be looking as you do this. Do not press to hard!
- Try and make sure that both tips touch the skin at the same time. Ask your partner if they felt one or two pressure points.
- If your partner felt one point, spread the tips of the clip a bit further apart, then touch the back of your partners hand again. If your partner felt two points, push the tips a bit closer together and test again.
- Measure the distance at which your partner can feel two points.
- Now try the same thing on different parts of the body and record the distances.
What's happening?
The receptors in our skin are not distributed in a uniform way around our body. Some places, such as our finger and lips, have more touch receptors than other parts of our body, such as our backs. That is one reason why we are more sensitive to touch on our fingers and face than on our backs.
Fun Animals Fact
Rats breed so quickly that in just 18 months, 2 rats could have created over 1 million relatives.
The blue whale can produce the loudest sound of any animal. At 188 decibels, the noise can be detected over 800 kilometres away.
Horses and cows sleep while standing up.
Giant Arctic jellyfish have tentacles that can reach over 36 metres in length.
Locusts have leg muscles that are about 1000 times more powerful than an equal weight of human muscle.
Hummingbirds are so agile and have such good control that they can fly backwards.
Instead of bones, sharks have a skeleton made from cartilage.
Insects such as bees, mosquitoes and cicadas make noise by rapidly moving their wings.
The horn of a rhinoceros is made from compacted hair rather than bone or another substance.
Sharks lay the biggest eggs in the world.
Even when a snake has its eyes closed, it can still see through its eyelids.
Unlike humans, sheep have four stomachs, each one helps them digest the food they eat.
Despite the white, fluffy appearance of Polar Bears fur (which is transparent), it actually has black skin.
As well as being a famous Looney Tunes character, the Tasmanian Devil is a real animal that is only found in the wild in Tasmania, Australia. It is the largest carnivorous marsupial in the world.
The average housefly only lives for 2 or 3 weeks.
Mosquitoes can be annoying insects but did you know that it's only the female mosquito that actually bites humans.
Cats use their whiskers to check whether a space is too small for them to fit through or not.
What does ecology have to do with me?
What is Ecology?
Ecology is the study of the relationships between living organisms, including humans, and their physical environment; it seeks to understand the vital connections between plants and animals and the world around them. Ecology also provides information about the benefits of ecosystems and how we can use Earth's resources in ways that leave the environment healthy for future generations.
Ecologists study these relationships among organisms and habitats of many different sizes, ranging from the study of microscopic bacteria growing in a fish tank, to the complex interactions between the thousands of plant, animal, and other communities found in a desert.
Ecologists also study many kinds of environments. For example, ecologists may study microbes living in the soil under your feet or animals and plants in a rainforest or the ocean.
The Role of Ecology in Our Lives
The many specialties within ecology, such as marine, vegetation, and statistical ecology, provide us with information to better understand the world around us. This information also can help us improve our environment, manage our natural resources, and protect human health. The following examples illustrate just a few of the ways that ecological knowledge has positively influenced our lives.
Improving Our Environment
Pollution From Laundry Detergents And Fertilizers
In the 1960s, ecological research identified two of the major causes of poor water quality in lakes and streams-phosphorous and nitrogen-which were found in large amounts in laundry detergents and fertilizers. Provided with this information, citizens were able to take the necessary steps to help restore their communities' lakes and streams-many of which are once again popular for fishing and swimming.
Non-Native or Introduced Species Invasions
Some non-native species (plants, animals, microbes, and fungi not originally from a given area) threaten our forests, croplands, lakes, and other ecosystems. Introduced species, such as the kudzu vine shown below, do this by competing with plants and animals that were originally there, often damaging the environment in the process. For example, the gypsy moth, a native of Europe and Asia, wreaks havoc on great swaths of forest lands by defoliating, or eating the leaves off of trees. At first, highly toxic chemicals, which also poisoned other animals, were the only methods available to control this introduced pest. By targeting vulnerable stages in the moths' life cycle, ecologists devised less toxic approaches to control their numbers.
Public Health
Natural Services
Ecologists have discovered that marshes and wetlands filter toxins and other impurities from water. Communities can reap the benefit of this ecological service. Leaving some of these filtering ecosystems intact can reduce the burden on water treatment plants that have been built to perform the same service. By using natural filtering systems, we have the option to build fewer new treatment plants.
Biomedical Contributions
Ecologists have discovered that many plants and animals produce chemicals that protect them from predators and diseases. Some of these same chemicals have been synthesized by scientists or harvested from the organism and used to treat human diseases. For example, the Pacific Yew tree produces a substance which is used in cancer treatments. Another example is a substance found in horseshoe crabs, hemolymph, that is used in leukemia treatments.
Lyme Disease
Lyme Disease is a potentially serious bacterial infection that is transmitted to humans by certain ticks. Ecological studies have found that people are more likely to get Lyme disease when acorns are plentiful. Why? Because mice and deer, which carry the disease and the ticks, feed on acorns. More acorns usually mean more mice and deer, providing a favorable environment for large populations of ticks to flourish. Knowing the connections between acorns, deer, mice, and ticks, ecologists are able to predict the likelihood of infection and let people know when they need to be more careful when outdoors.
Natural Resource Management
Endangered Species Protection
Some of our nation's most cherished species, such as the bald eagle and peregrine falcon, as well as countless other less familiar species, like the Virginia Big-Eared Bat and the American Burying Beetle, have either been brought back from the brink of extinction or their populations have been stabilized. These successes are the result of successful captive breeding efforts, reintroduction methods, and a greater understanding of species, in part because of ecological research.
Forestry Solutions
Ecological concepts have been applied to forest management and are slowly being integrated into traditional forest science. For example, ecological studies have shown that fire plays a key role in maintaining healthy forest ecosystems in certain types of forests. This knowledge has encouraged more research to find ways to use controlled fires to prevent unpredictable and costly wildfires.
Agricultural Solutions
Biological control is a technique that uses the natural enemies and predators of pests to control damage to crops. It is based in part on knowing the ecology of pests, which is used to understand when and where they are the most vulnerable to their enemies. Biological control alleviates crop damage by insects, saves money, and decreases problem associated with pesticides.
Fishing Solutions
Ecological research has shown that estuaries are nursery grounds for fish populations that live in coastal waters, an important reason to protect these areas. Ecological research has also identified obstacles, such as dams, that fish encounter when returning to their breeding areas. This information has been used to help design structures for fish so they can move around these obstacles to reach their breeding areas.
Common Terms
An ecosystem is any geographic area that includes all of the organisms and nonliving parts of their physical environment. An ecosystem can be a natural wilderness area, a suburban lake or forest, or a heavily used area such as a city. The more natural an ecosystem is, the more ecosystem services it provides. These include cleansing the water (wetlands and marshes) and air (forests), pollinating crops and other important plants (insects, birds, bats), and absorbing and detoxifying pollutants (soils and plants).
Short for biological diversity, biodiversity is the range of variation found among microorganisms, plants, fungi, and animals. Some of this variation is found within species, such as differences in shapes and colors of the flowers of a single species of plants. Biodiversity also includes the richness of species of living organisms on earth.
The environment is the surroundings of an organism including the physical and chemical environment, and other organisms with which it comes into contact. This term is most frequently used in a human context, often referring to factors affecting our quality of life.
Natural Resources
Natural resources are living and nonliving materials in the environment that are used by humans. There are two types: renewable (wildlife, fish, timber, water) and nonrenewable (fossil fuels and minerals).
A group of individuals belonging to one species (of bacteria, fungi, plant, or animal) living in an area.
Populations of organisms of different species that interact with one another.
Where Can I Go For More Information or Assistance?
If you are interested in learning more about ecology, or would like to know what you can do to become involved, a number of resources are at your disposal. Public and university libraries offer articles, journals, and books on a range of ecological research.
Many environmental organizations have developed educational materials that focus on species and ecosystems, and offer tips on becoming involved in community activities that relate to the environment. Finally, professional ecological organizations can connect you with scientific experts in all types of ecological study, from those that specialize in wetland ecology, to those that focus on endangered species, to those whose work emphasizes city environments.