why DID we evolve into humans?

I wanted to expand on the original questions/points posted. In my post, I'm going to refrain from using technical terms like species to help keep the topic from being bogged down with criticism on my definition or use of the word. Unfortunately, I can't think of a general word for "evolution" or natural selection, so I'm just going to use "evolution" when I mean whatever mechanism is responsible for getting us from primordial soup to human.When we look at humans now, we can see some complex mechanisms, for example: eyes. My next thoughts/questions could apply to other organs/mechanisms in humans, but I think it's best to only focus on one thing at a time so the topic doesn't get diluted. If anyone wants to comment though, feel free to use whatever example you want.Humans don't have exclusive claim to eyes. Eyes exist is a many other creatures. I think that some creatures have eyes that are better in some ways than ours, some are worse, or completely different (I'm thinking of insects with compound eyes)In the case of some animals, their eyes operate very similar to our eyes, even being able to see almost exactly like we do.My comparisons about eyes are very general, because I don't have specialized knowledge on eyes, so I'm drawing these conclusions from listening to the Discover Channel and Animal Planet. I don't believe I need more specifics though for my question.If I understand evolution correctly, all human/animal life descended form one species (if you go back far enough). So at what point did eyes first come into existence? Since most creatures have eyes, they must have started pretty far back, right? For if they didn't, that means that multiple creatures developed similar eyes simultaneously.If they did start before whatever split happened to our common ancestor, then how could something so complex have evolved even before we were all different species?Our bodies are filled with complexities, many of which are shared among at least one other group of creatures or another. How can complexities that are so similar have developed independently from each other? Of if they did develop early on, what kind of creature possessed all these traits, then evolved into birds, cats, etc?I admit to being a novice at this, so I'm hoping for some good explanations.

Thanks for the link. I read the text and watched the little video. I thought the logic was poor in the video. Also, there was a severe lack of details and information about eye evolution, however, it might have been toned down to address a specific audience, so I can forgive the lack of information just not the logic.But, I wasn’t really concerned specifically the eye, or how or why it evolved, but the order it evolved. Our bodies are so complex, when did all that complexity get there?According to evolution, was it before our last common ancestor (common to all mammals, and maybe even fish and insects), or did all the mammals etc develop all this complexity independently from each other?In other words: was there some creature that had eyes, ears, liver, heart, spleen, (all that good stuff), and through mutations, some gradually became giraffes, others become people, or cats, bears, etc?I understand no one claims we went from (for example) bacteria to human in one step, that every change was very gradual, so please don’t get sidetracked on my language above.Thanks.

I’m not an expert in autonomy, but I know that many creatures share some of the same organs that we do. Many different creatures have ears, eyes, liver, and kidneys. I’m sure that there are many more.So you are saying these organs evolved in our common ancestor (maybe a fish, in your example), meaning we had a biologically complete common ancestor. I don’t know of any organs we have that no other creature has, so a complete ancestor means biologically, they had all the organs we do now, they just weren’t human.At that point, we had a non-human ancestor with everything it needed to change into a human. So it then grew legs (over small steps, not in one big jump), arms, etc, learned to stand upright, and then became smart (to become human)Others could have evolved into dogs, lions, etc. through the same small step evolution process.So does that sum this up?