system
Given the following post, respond as if you're commenting on Reddit:
human
I believe that Creationism is the only explanation for the existence of such diverse life on Earth. CMV

Hello, here's my two cents before everyone gets started. Please let me know if I have any information wrong or if I could be posting this in a better place:

* I am a Catholic, however, I would like this to be a discussion of pure science. I realize evolution does exist to a certain extent. I am questioning that extent.
* From what I understand, the commonly accepted theory of evolution *(please tell me if I am using the incorrect word)* is that life, not necessarily as we know it, but life nonetheless was a happy accident due to faults and fractures from rocks.
* From that, it is my understanding that these fractures formed the simplest of life--that of a single-celled organism. I would find it harder to believe that rock fractures could create a multiple-celled organism that was on the surface of the planet (above the crust, underwater counts as surface)
* Continuing, I find it incredibly hard--if not downright impossible--to believe that this single-celled organism was able to survive, let alone reproduce and become populous enough to evolve into so many different classes of animals (from birds to fish to insects). 
* In essence, I suppose my question is about how a single cell was able to evolve into so many different types of things, or why it would be bothered to evolve, because single celled organisms still exist.

Thanks to any reponses.

Edit: I unfortunately have been called in to work. I will be back in about 5 hours.

Edit2: I have returned and read through many of your responses. I'd like to thank you all very much for taking the time to respond and provide me with some great information on the subjects I was questioning; this is exactly what I was looking for. As of now, my view has not been changed due to much of this being over my head. However, as I read and research more, you fine people may well  accomplish your goals. Thanks again to everyone.
gpt
I don't think evolution talks about life coming from rocks. Evolution talks about the origin of life being self-assembling proteins and amino acids that were able to induce copies of themselves. It started with self-forming lipid micelles that went on to absorb these proteins. The longer proteins increased the osmotic pressure of the micelles, making them larger. Larger micelles "eat" smaller micelles when they come into contact. This were the first "cells." Eventually, the proteins that were larger and "coded" for longer proteins were selected for, and at some point the replication mechanisms became more and more complex.

Once we had the first single-celled organism, it continued to spread and replicate. As it spread to different environments, different traits were selected for. The first colony-type cells began to develop. Herd behavior as well as signaling developed as cells that shared genetic material helped each other survive so that their "brothers" would pass on their genes. This is the origin of altruism.

Eventually colonies evolved into the first complex organisms, with cell specialization. Each cell had the same genetic information, but signaling affected which genes were expressed in an individual.

From there, the multicellular organisms also spread throughout the world and all the environments, and as they were separated by huge distances, diversity began to appear. Since evolution is a random process, there were millions and millions of adaptations that occurred in one organism but not another. This is the origin of the great variation we see today.

Your last point is interesting--why evolve into an animal if being a bacterial cell seems to work out just fine?

Well, its about niche. The way things are now, there really isn't any more room for bacteria. The "microspace" is all filled up, and in order to break into it, you'd have to be a more efficient bacterial organism. So instead, bigger organisms are favored for their ability to gather resources and survive. However, as these new organisms moved into "unclaimed" ecospheres, they filled these up too. Its why we have insects, birds, fish, plants and humans. Each is able to survive because for the most part, they do not compete with each other for the same resources. Think about it, plants primarily consume sunlight, but animals do not. So both an exists in the same square meter of earth without getting in each other's way. They can even work together to survive better. Just like humans and the bacteria in our digestive tract can work together for mutual benefit.

The bacteria don't exist because its "better" to be a bacteria, they exist simply because they can.