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Re: so H sapiens evolved from H. erectus?
Rohinton Collins (rohinton@collins.prestel.co.uk)
4 Nov 1996 23:14:37 GMT
Homo sapiens is largely believed to have evolved in Africa from Homo
erectus. The oldest H. sapiens fossils were found in East Africa, dated at
around 200,000 ya. H. sapiens is then thought to have colonised the rest of
the world, displacing all other hominid species including Homo erectus,
archaic H. sapiens and H. neanderthalensis. This is known as the 'Out of
Africa' or 'Displacement' theory.
Another theory, called the 'multiregional hypothesis' states that from the
original exodus of H. erectus from Africa, there was only ever one,
world-wide, hominid species, which gradually and globally evolved into H.
sapiens. The theory holds that gene flow was responsible for maintaining a
single species.
I think this latter theory is fallacious however, since it flies in the
face of what we know and understand about evolution and speciation. There
were many distinct hominid species around that time whose lifespan
(species) overlap, casting grave doubt upon the supposed gene flow. Further
this theory has gradualism written all over it, and in recent times
punctuated equilibrium has been shown to be a better description of
evolution. For the most part, species are very stable and may remain
genetically similar for millions of years, indeed in some species
(admittedly invertebrate) tens or hundreds of millions of years. And it is
well known that due to genetic momentum, speciation is very unlikely to
occur in a large gene pool such as that described above. It is much more
likely to occur in a genetic bottleneck.
Hoped this had answered your question.
Regards,
Roh
daniel hwang <dhwang@students.uiuc.edu> wrote in article
<55lo30$6mc@vixen.cso.uiuc.edu>...
> given that H. erectus is found all over asia and africa....which
>
> H. erectus group?
> --
>
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