Re: Hominid speciation, was h

KathieDon (
22 Jul 1995 18:44:38 -0400

I think that hybridization is a reasonable way of resolving the "H.
habilis" question. Of course we can't know what the genetic distances
were like, but I think it reasonable to suppose that they were small
enough that fertile cross-breeds between, say, robust australopithecines
and whatever 1470 was.
The picture, then, is something like this: at about 2 million years
ago, we don't have clearly defined species, but rather a continuous gene
pool with strongly developed clines--the equivalent of "racial" variation.
Out of this pool we eventually get H. erectus and a robust species.
These last two apparently didn't interbreed because we don't have (at
least I don't think we have) intermediate morpholgies, not after about 1.7
Could this be right? And if so, is the "pool" continuous with the
ancestral ramidus-like populations? That would mean that from about 4
and a half million years ago, to about 1.7 million years ago, we had
diversification at the morphological (and presumably behavioral) level
with little or not diversification at the genetic level. An interesting
set of affairs.
Any comment on this "Just So" story would be much appreciated.

Carl Sachs