Re: AAT Theory
chris brochu (gator@mail.utexas.edu)
27 Oct 1995 16:39:26 GMT
In article <46qrg6$ech@news.cc.ucf.edu> Thomas Clarke,
clarke@acme.ist.ucf.edu writes:
>> 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?
>
>Where is the evidence against it? I would argue that no matter
>which scenario you like, that hairlessness matches bipedalism.
In other words, it's completely untestable. "Untestable" and "wrong" are
not the same thing, but untestable speculations are still not valid as
evidence.
>> 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).
> ^^^^^^^^^^^^ not in my dictionary, can you define please
Autapomorphy = uniquely derived character state. On a cladogram, it
diagnoses a terminal taxon without linking it to something else. On a
phylogeny of primates, hairlessness is an autapomorphy for Homo sapiens -
it is only known in one taxon, and does not link it to anything else.
Of course, if we found a habilis carcass frozen in ice, that might
change. But for now, we are only able to score this character for extant
taxa.
>> 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 ...
>
>AAS is irrelevant as I argue above.
Relevancy is not the issue. Testability is. Hair loss is consistent
with either scenario, however valid each scenario is, and is useless as
evidence.
chris
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