Re: Dissecting the Aquatic Ape: Bipedalism
Paul Crowley (Paul@crowleyp.demon.co.uk)
Sat, 27 Jul 96 23:25:45 GMT
In article <4t0ljo$hts@portal.gmu.edu>
herwin@mason2.gmu.edu "HARRY R. ERWIN" writes:
> : / - - - - - Knuckle-walker(s)
> : {a} Ancestral Ape <
> : \_ _ _ _ _ _ Bipedal hominid
>
> : {b} Ancestral Ape - - -> Proto-chimpanzee - - - -> Chimpanzee
> : \_ _ _ _ _ _ _ > Bipedal Hominid
>
> Last I checked (February), the split was still a bush. I did read a good
> article (November) that argued (based on sequencing data) that the three
> lineages diverged within a couple of hundreds of thousands of years,
> hence effectively simultaneously.
Did this split happen at the same time (or shortly after) the
Ancestral Ape descended from the trees to become largely territorial?
The likelihood must be reckoned to be small.
The niche for a ground-living large ape, that used trees for food
and for nocturnal refuge, had been available for tens of millions
of years. Surely the probability must be that it was exploited
for several million years before the split occurred. The finding
of Ankarapithecus Meteai must support this. A species that had
adapted to this niche would have become widespread throughout
tropical Africa and probably beyond. (Turkey is nowhere near the
tropics.)
The split would have resulted from small populations of this main
species becoming isolated. So which was the (widespread) parent
species? It certainly wasn't the hominid branch. Was it the
chimpanzee or the gorilla? Can DNA studies provide indications
of genetic variability to the extent that, say, an 10 Myr-old
species could be distinguished from a 6 Myr-old one? Have any
such studies been attempted? For example, how far back are the
chimpanzee and gorilla "Eves" and "Adams"?
Paul.
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