Re: Aquatic Apes 3 of 5
Phil Nicholls (pn8886@csc.albany.edu)
11 Dec 1994 15:13:55 GMT
In article <lmm5-101294191802@132.236.78.46>, loopy <lmm5@cornell.edu> wrote:
>In article <3c0ul8$cvd@newsbf01.news.aol.com>, patdooley@aol.com (Pat
>Dooley) wrote:
>
>> He misses the point that bipdalism is much less efficient for the other
>> apes
>> than their usual mode of locomotion. Conversely, most of us humans avoid
>> knuckle walking.
>
>We don't knuckle-walk because it is a very specialized form of locomotion,
>just like bipedalism. If the first biped was an inefficient runner or
>walker, then that provides evolutionary pressure for that hominid to become
>a better runner or walker.
>
>> How do we know the common ancestror of around 12 mya was not a knuckle
>> walker. About all we do know for certain is that it wasn't truly bipedal.
>
>strictly speaking we don't know either, since we haven't found fossils from
>that period.
Actually we do. Knuckle-walking leaves facets on the metacarpals that are
the result of hyperextention. These are present in the skeltons of newborn
apes but are not present in any hominids. Knuckle-walking is most likely
a derived behavior of pongids, specifically the chimpanzee-gorilla clade.
There are also no facets of this kind on the bones of any fossil apes.
As for bipedality, there is no evidence of skeletal adaptations to
bipedalism in modern apes or fossil apes so it is likely a derived
condition for hominids.
My own believe is that bipedalism originated on the forest floor and
was extended onto the savannah as proto-hominids exploited the zone
between savannah and forest -- quick forays to clumps of trees that
were about 30 m or so away from the main forest, gather food and
return with it to the relative saftey of the forest.
But then I don't believe Lucy is a direct ancestor of modern hominids
either.
--
Philip "Chris" Nicholls Department of Anthropology
Institute for Hydrohominoid Studies SUNY Albany
University of Ediacara pn8886@cnsunix.albany.edu
"Semper Alouatta"
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