system
Given the following post, respond as if you're commenting on Reddit:
human
How did nature evolve insects that look like sticks, or leaves, or even snakes? Am I to understand that was just random mutations and natural selection did all the work?

Bear with me here.  I'm trying to learn the ins and outs of evolution as it was taught only sparingly in my high school biology classes.  I'm just about to finish Richard Dawkins' *The Greatest Show On Earth* and what I feel the entire book is explaining (in between the impossibly frequent and often meaningless tangents) is that random gene mutations and natural selection are pretty well all that has driven the shaping of all modern organisms from our one common ancestor.

So for example, is it true then that nature has, by purely random happenstance, mutated an insect to look more and more stick like over countless generations, thus making them more able to camouflage themselves and survive, that has given us our modern day stick bug?  I've seen them look virtually identical to real sticks, which absolutely astounds me.  

Now I don't believe in intelligent design after reading about plenty of evidence that smashes it to bits, so I guess I'm just asking if I'm understanding this correctly? (The aforementioned book has not been the greatest, in my opinion.)

But if that is how it's done... then touché, nature.  Mind = blown.
gpt
Yep, natural selection was the guiding process for the development of the amazing camouflage and mimicry abilities within the insects you are referring to.  Mutations occur sparingly within a population, and most are detrimental to the organism.  However, there is the rare occurrence that a mutation will boost the reproductive success of an organism.  This beneficial mutation will spread to the following generations until the entire population acquires this trait.  Keep in mind that insects have been on this planet for quite some time.  There has been ample time for organisms to develop some pretty crazy attributes.