Re: Bipedalism and theorizing... was Re: Morgan and creationists
Paul Crowley (Paul@crowleyp.demon.co.uk)
Thu, 03 Oct 96 10:54:27 GMT
In article <Dyo3Cu.GH1@inter.NL.net>
ghanenbu@inter.nl.net "Gerrit Hanenburg" writes:
> That's why I think that reorganization of the pelvic region and lower
> limbs is crucial,and happened early in hominid evolution.
> It may have started during a stage when the main function of
> bipedalism was postural and not yet locomotory.^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^
What does "the main function of bipedalism was postural" mean?
Such changes must have been very costly (in all kinds of ways)
and probably seriously affected the existing form of locomotion.
What scenario do you envisage that could have created such strong
selective pressures?
> -In case of a Pan/Gorilla clade,the LCA of humans and African apes was
> a knucklewalker and the character was secondarily lost by the
> hominids,or the LCA was not a knucklewalker and the character was
> acquired later by the LCA of the African apes after the split from the
> hominids.
> -In case of a Pan/Homo clade,The LCA of humans and chimps was a
> knucklewalker and the character was secondarily lost by hominids,or
> the LCA was not a knucklewalker and the character was acquired
> independently by Gorilla and Pan.
Origin of LCA / Chimp (knuckle-walker)
O>--------[unknown locomotion]------ Gorilla (knuckle-walker)
(20mya? 15mya? 10mya?) \ Hominid (bipedal - NEW)
Given that the hominid bipedal locomotion was new, what is
the most parsimonious suggestion for the "unknown locomotion"?
Paul.
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