Re: Bipedalism and theorizing... was Re: Morgan and creationists
Phillip Bigelow (bh162@scn.org)
2 Aug 1996 23:45:42 GMT
herwin@mason2.gmu.edu (HARRY R. ERWIN) wrote:
>
>2. The issue of motor programs is a lot more important than
>non-specialists are aware.
Undoubtably. But without fossilizable motor program evidence, we are left to
speculate
on what phylogenetic route(s) motor program evolution in Primates went. In other
words, was motor progam evolution a "leader" in biped evolution, was it a "follower"
in biped evolution, or was it simply a "co-evolver" in biped evolution?
>From your perspective as a neurologic specialist, can you provide us with
any concrete ways in which your discipline can actually productively contribute to
this phylogeny discussion?
>Now bring an orthograde suspensory primate down to the ground. The motor
>program they use in the trees is suspensory climbing, and that does not
>convert easily into either terrestrial quadrupedalism or bipedalism.
Perhaps not. But it appears to be somewhat of a non-issue here. If arboreal
suspensory movement is considered to be
a primitive trait for Primates, then at least some ground-anthropoids seem to
have conquered this "motor program roadblock to quadrupedalism
and bipedalism" fairly well; e.g., those being the gorillas, chimpanzees, and
hominids.
The corrolary to this fact is that, PERHAPS, just perhaps, the evolutionary
PATHWAY of motor programming in the hominoid brain is not as complicated
as is, say, the influences of a mosaic of niche and ecological changes
that probably affected most anthropoids around 5 mya.
>
>Note that if you put a orthograde suspensory primate into deep water, it
>will swim with its arms--that's what the motor program is biased towards.
>Bipedal locomotion in water is wading.
An experiment involving an orthograde suspensory primate placed in deep water is
considerably different than a researcher observing a biped in shallow water.
Bad comparison, Harry. What do bipeds do when placed in deep water? What do
suspensory primates do when placed in very shallow water? Is there any overlap in
locomotor motions between the two morphotypes when placed in similar water depths?
How "plastic" is the adaptation levels of individuals in such circumstances?
<pb>
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