Re: Bipedalism and theorizing... was Re: Morgan and creationists
Paul Crowley (Paul@crowleyp.demon.co.uk)
Fri, 27 Sep 96 07:57:22 GMT
In article <01bbab90$83ecdfc0$1e2470c2@jdwaters.dircon.co.uk>
jdwaters@dircon.co.uk "John Waters" writes:
> Paul Crowley <Paul@crowleyp.demon.co.uk> wrote in article > > >
>
> > No, No. You're missing my point. Forget rest stops. I'm saying
> > that the female must have put the infant down for particular
> > reasons arising from the new niche (probably one of wading and
> > swimming). This was a drastic break with a >65 Myr primate
> > behaviour.
>
> JW: Yes, I did miss your point; and probably a lot of previous
> correspondence on the matter. As you say, such a development
> would be a drastic break with past primate behaviour. Too
> drastic in my opinion.
>
> To me, it is inconceivable that a relatively advanced primate
> mother would put down her new born baby, and go off wading or
> swimming.
I glad you appreciate the drastic nature of the behaviour
(although you've overstated it by putting in "new-born" and
apparently assuming that the infant was left alone). The point
is that this radical change in behaviour *was_adopted* by our
ancestors at some stage. Human infants are put down; for a
long time (several million years) hominid mothers have not been
carrying infants close to their bodies, as all their primate
ancestors did, and all their primate relatives still do.
Was this drastic change in behaviour adopted for no particular
reason at some vague and uncertain time (as traditional PA
thinking has it)? Or was it associated with the other
distinctive hominid adaptations - such as bipedalism? Since
bipedal feet are not adapted for grasping, the two changes are
almost certainly linked.
As you have emphasised, early hominids would be highly social.
The sharing of infant care would have been the major barrier,
but if the niche made it essential, then it would have happened.
H.s.s. mothers have no great problems about it. When did they
acquire this characteristic - unique among the primates ? When
it started it would have followed present patterns: i.e. only
older infants would be left in a sister's, mother's or sibling's
care, while the female foraged. New-born infants would probably
be carried as much as possible.
You have to face up to the facts: This pattern *was* adopted.
The infant was put down. It may be unlikely, but it's there.
If you can't explain it you haven't got a theory of human
evolution.
> JW: An extension of the period of helplessness would not come
> about simply through infantile inactivity.
Why not? The more active infants would eliminate themselves and
leave no descendants. There's no mechanism more effective than
that.
Paul.
|