Re: An alternative to ST and AAT
Paul Crowley (Paul@crowleyp.demon.co.uk)
Thu, 31 Oct 96 21:24:38 GMT
In article <schmal-3010962256250001@ppp-14174.firstnethou.com>
schmal@firstnethou.com "T&B Schmal" writes:
> I think the *base* case is that as members of the LCA gradually became
> more bipedal they gradually became better at terrestrial progression.
> This seems like the simplest and most obvious place to start.
But bipedalism and quadrupedalism are two completely different
kinds of progression. If you get better at one, you necessarily
get worse at the other. A change from one to the other must
entail a deterioration (for at least ~100 Kyr).
> The alternative hypothesis, that as members of the LCA gradually became
> more bipedal they gradually became worse(!) at terrestrial progression,
> needs to have the case made for it.
Indeed! That's the whole mystery of bipedalism. It should not
have happened. It does need special justification - especially
when you think of the mother/infant dyad. It did not happen just
because the vegetation got a bit thinner. This is the fundamental
problem of human evolution.
Paul.
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