Evolution (Introduction)

by David Turell , Tuesday, October 13, 2009, 16:06 (5519 days ago) @ dhw


> C.O. Lovejoy: The discovery of Ar. Ramidus also requires rejection of theories that presume a chimpanzee or gorilla-like ancestor to explain habitual upright walking. Ar. Ramidus was fully capable of bipedality and had evolved a substantially modified pelvis and foot with which to walk upright. -Lovejoy's summary is here: (also posted 10/12/09, 16:07)- http://www.sciencemag.org/cgi/content/full/326/5949/74/DC1 -> 1) Normally when I read "the common ancestor", I assume it's the ancestor common to humans and apes, but if apes branched off the hominid line, what was the common ancestor common to? And don't apes then become irrelevant to human ancestry?-Your last sentence is the correct conclusion. It is very important to understand that the prevailing opinion up until this juncture with Ardi is that we humans decended from an ape-like ancestor. Now that appears to not be the case. If there is a common ancestor, and one would think there must be, since evolution seems to act like a tree with branching, it may well be more hominid-like than ape-like, a complete reversal of previous thought.--> 2) If apes did indeed branch off from humans, is it not possible that Ardi's long arms and opposable toes represent a development from the shorter arms and non-opposable toes of non-tree-climbing hominids? And that the all-important projecting canine (though I thought that was a purely male feature) plus aggressive behaviour came after Ardi? In other words, that she's moving away from the hominid line towards chimpanzeedom?-No, to answer that question, look at Lucy, a million or so years down the line. Ardi is a development toward the Luci skeleton formation, with a loss of the prehensile big toe, and other changes.
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> 3) Ardi is estimated to be 4.4 million years old. I thought the conventional theory was that humans and apes split from the "common ancestor" about 6 million years ago, i.e. long before Ardi hit the ground. So if chimps and gorillas already existed, say, a million or so years before her, how does she disprove the theory of the chimpanzee-like ancestor? Wouldn't we need to know for sure that chimps did NOT exist before her?-Chimps may have branched off the main line (hominid)as stated above and established their general appearance immediately, and have been static ever since. We just don't know. But as I finish Schroeder I'll be reading "Not A Chimp", by Jeremy Taylor (Channel 4 in the UK), which looks at the specific genetic differences, small in total percentage, but extremely large in effect.
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> I apologize for the ignorance underlying these questions, but perhaps I'm not the only one in need of enlightenment.-These findings are turning Darwin's assumptions on their head. If they turn out to be true, then we are definitely different in kind, and a universal intelligence, or God, must philosophically rear its ugly head!