Re: Hair and AAS
David Froehlich (eohippus@curly.cc.utexas.edu)
Mon, 16 Oct 1995 16:34:39 -0500
On 15 Oct 1995, Tom Clarke wrote:
> Not at all. I thought the current thought is that man and apes
> had a common ancestor about 6 million years ago in the Miocene.
> DNA evidence is crucial here as well as fossils. Either the common
> ancestor had hair, or it didn't. If it did then the assumption is
> met. If not then the problem is to explain why three (two?) apes
> gained hair.
AAS assumes that hairlesness is an aquired feature from some aquatic
stage. My arguement is that we cannot know where hairlessness occured.
If (as in AAS) the aquatic phase caused the loss of hair then you are
implicitly stating that all the australopithecines are hairless (they
postdate the AAS transition). Where is the evidence for this? All we
have is modern humans without hair and hominoids with hair. From the
phylogeny of hominoids, it is obvious that the lack of hair in humans is
an autapomorphy (at least by the principle of parsimony). What I
pointing out is that hairlessness could have occured any time after
the last common ancestor of humans and chimps (or if you prefer,
chimps and gorillas) and before we have evidence of it (possibly cave art
depictions???). AAS assumes that it is functionally related to an
aquatic episode (this basically assumes what you are trying to
demonstrate, that hair was lost in an aquatic episode). I do not buy
this assumption. Please defend it.
David J. Froehlich Phone: 512-471-6088
Vertebrate Paleontology Laboratory Fax: 512-471-5973
J.J. Pickle Research Campus
The University of Texas, Austin, Texas 78712
|