Joined: Feb. 2008
speciation hasn't been observed nor is there evidence for it because it can't happen. Speaking from a strictly atheist, scientific viewpoint, the proof of speciation is no proof, just sheer speculation and fantasizing while at the same time disregarding the limitations of reproduction within species.
Each species has its own limited gene pool, and can only produce its own species. Any variance or differing traits are still part of the species, so a taller human is still a human, etc... There's no dog with wings, or hairless monkeys that resemble hairless humans. So natural selection can't progress anything because all these traits still propogate the same species. Evolution would have to rely on nothing but random mutations that need to be so alien as to help propogate a different species, such as a cow with a giraffe's neck. Then, these mutations need to have successive mutations in order to bring about a larger change, such as a cow's neck becoming longer and longer. This is not only extremely rare, but physically impossible. These preliminary mutations aren't even advantageous for natural selection to work on them, nor would they necessarily always turn out properly in the new generation. If an ape is to become a human, it would have to somehow be born bipedal and start walking bipedally, and conceiving bipedal apes. If evolution has a starting point, then these preliminary changes should be seen today, as random mutations don't take millions of years to happen, because they aren't based on natural selection. We should be able to see monkeys being born bipedal, or hairless, which would then begin the process of natural selection if these traits are even advantageous, then they would be passed on. BUT, there's more problems. These apes will still mate with apes, and it's not possible to make an entirely new species while you're conceiving with the same one all the time. A hairless monkey would still be a monkey, there would be no reason for it to speciate and not be able to reproduce with monkeys anymore.
Alas we see that no physical mutation has any beneficial effects for animals or humans, nor do they turn humans into another species. If humans can evolve, then we should see kids who are sometimes born with 3 arms, to be able to live and use their arms productively, but this is the opposite. Most physical mutations even reduce fertility and increase chances of miscarriage such as Down's Syndrome.