Biology, programming, linguistics, phylogeny, systematics....
Actually, if Chimpanzees and apes, etc. have an ape-like ancestor, that would either prove they are different species of the same kind, or they perhaps did evolve from an ape-like ancestor. But what did it look like if not like an ape?Today, Neanderthals, Cro-Magnon Man, Homo Erectus, etc. have all been considered to be pretty much completely human. Shouldn't scientists be looking for a human-like ancestor, one that looked pretty much like a human?All I see are two distinct lines of descent, one line of monkey kind, but they are just different kinds of monkeys and are all at the top of the branches. The other line is human-kind, but they are all at the top of the branches. Is there anything to suggest the ancient human-like ancestor would be somehow related to the ape-like ancestor, if they actually ever found either one?
Cro-Magnon man is completely human. Neandertals are a related species, and Homo erectus is a slightly more distant species, but they are both very humanlike.What you are missing is the fairly seamless transition from species that we would probably call "apes" to humans and humanlike forms. This illustration doesn't show it, but Ardipithecus is very chimpanzee-like, to the point that it might actually be our last common ancestor with chimps (and is at least very close to it). Praeanthropus is also quite chimplike, especially in the cranium and torso, but it shows some more humanlike characteristics, most saliently an erect stance (at least in later species). Early Homo and early Australopithecus are very similar to and overlap with late Praeanthropus. There is a gradual accumulation of human traits in what begins as a fairly chimpanzee-like lineage.I'm not sure what you mean by "one line of monkey kind". The term "monkey" is a rather useless one. There are many, many lineages in the simian tree, and humans are one twig in that tree (albeit the most successful twig, by far, and certainly one of the strangest twigs). This diagram focuses on the human-chimpanzee group, so are you referring to chimpanzees (which are generally considered apes, not monkeys)? Or are you considering this diagram as well? I guess I'm not exactly sure what you are asking.
Hi! I just followed your name from your last comment on Eric Michael Johnson's blog. Really interesting stuff! I'm particularly looking forward to the complete "The Case for human evolution" (especially the 126 morphological characteristics you used for your graph).As for Arv Edgeworth's comment, every time I hear someone speaking of biological "kinds", there is a little red flag in my mind. And a quick Google search tends to confirm, if it is indeed the same Mr. Edgeworth, that he is a creationist minister of the kind who thinks dinosaurs were on Noah's Ark and that every living creature ate plants before the flood, so you'd have a lot of work to do before you'd convince him...http://www.truthandscience.net/endorsements.htmAnd as many of them, he is a specialist on a wide array of subjects, including chromium isotopes...http://www.nature.com/news/2009/090909/full/news.2009.901.html
And, of course, since I posted this, the new Ardipithecus material has been published, showing that that genus is a very good ancestor candidate (although the new A. ramidus material is a bit too late to be the actual ancestor). It has chimpanzee-like traits (opposable toes, brow ridges, long arms, etc.), but it also has human-like traits (small canines, bowl-like pelvis, large heel, etc.). And in some ways its more "primitive" than either (small brain size). So, there you go, there's your convergence of chimpanzee and human lineages.