Re: Bipedalism and theorizing... was Re: Morgan and creationists
Nathan K. Edel (nate@coos.Dartmouth.EDU)
22 Jul 1996 10:01:59 GMT
Paul Crowley (Paul@crowleyp.demon.co.uk) wrote:
: Ape infants, when they're born, have arms and legs that are long
: enough to reach the mother's sides and have grasping hands and
: feet that are strong enough to hold and bear its weight. It's a
: design that goes a very long way back in primate evolution, maybe
: over 100 Myr. It was probably *the* distinctive primate
: adaptation. (Is there a primatologist in the house?) It required
: singleton births and suggests a nomadic arboreal existence.
(not a primatologist, but taking a primatology course...)
Grasping hands and feet are indeed a primitive characteristic of primates,
infant as well as adult, although I'm not sure whether it's safe to add the
the "long enough to reach the mother's sides..." part in all cases...
The distinctive (primitive) primate adaptions also include color vision
(actually a retained primitive mamalian trait, it's just very commonly lost
in other developed mammals), binocular vision, etc.
The distinctive adaptive trends among primates are increased brain to body
size ratio, increasingly altricial young, a replacement of claws with nails,
and a reduction in the importance of smell vs. the importance of vision,
with a corresponding reorganization of the brain.
: And why should early hominids have been hairy? The parsimonious
: and normal assumption is that all the distinctive features of a
: species were adopted at the point of speciation. Fossil or other
: data may modify this assumption, but we have no reason to modify
: it in respect of hair.
Yes, but that would place it somewhere between 30,000 and 1.6 Million years
ago depending on when you place the origins of H. sapiens -- a zoo in its
own regard... since hair and soft parts very rarely (practically never)
preserve, it is very difficult to prove anything with re: to the
hairiness/lack of hair of any species prior to H. sapiens -- or even of
archaic populations of our own species, to a lesser extent...
: > Since Australopithecines had brains not much
: > bigger than chimps it's not likely they had the pattern of postnatal
: > braingrowth of humans,but a pattern similar to chimps.We may therefore
: > assume that they had precocial infants that could cling to their
: > mothers shotly after birth.
:
: This is appalling logic. I know it's standard. That makes it even
: more appalling.
Until they find a sample of austalopithecine infants, that's going to be
tough to argue either way; I'm not sure what they infer from the Taung
specimen, but that's the only one I'm aware of...
Nate
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