Re: AAT Theory

chris brochu (
27 Oct 1995 16:39:26 GMT

In article <46qrg6$> Thomas Clarke, 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

>> 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

>> 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