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Re: 30,000 year old Homo erectus - ajava [1/1]
Timo Niroma (timo.niroma@tilmari.pp.fi)
19 Dec 1996 23:40:44 GMT
In article <32b8d81d.270384376@nntp.ix.netcom.com>, sarima@ix.netcom.com
(Stanley Friesen) says:
>
>pmanansala@csus.edu (Paul Kekai Manansala) wrote:
>>I'm not sure how it supports the Out of Africa hypothesis unless there
>>is some modification to the replacement concept.
>
>A. Because the Multi-regional theory require that all H. erectus
>populations evolved over time into H. sapiens populations, over the
>entire range. So, if the two forms really overlapped in time, then
>gradual conversion of one into the other throughout their area is
>contradicted.
>
>B. The replacement hypothesis only states that some time before modern
>times H. sapiens replaced all prior species of Homo. It really says
>nothing about the *timing* of that replacement.
>
>> Wolpoff argues that
>>certain non-adaptive traits are shared between Homo Erectus of Java
>>and modern Australians. If we accept genetic exchange, which Wolpoff
>>does, then the Out of Africa hypothesis might be supported but minus
the
>>total replacement theory.
>
>Retention of distinctive morphology *at* *all* for several 10's of
>thousands of years of population contact is impossible in the presence
>of any significant gene flow. The presence of a form with a definite
>H. erectus morphology at a 30Ka BP date is nearly absolute proof of
>*lack* of gene flow between H. sapiens and H. erectus. Ergo, Out-of-
>Africa.
>
>> However, there was no mention of genetic
>>exchange in the article, which still leaves the question open has to
how
>>modern humans in SE Asia/Pacific share certain non-selective
>>cranial features with Java Man (Homo Erectus).
>
>The point is that the presence of a H. erectu as a distinct population
>that late makes any genetic exchange virtually out of the question.
>
>In short, it pretty much demolishes Wolpoff's contention of shared
>non-adaptive traits. Either the traits really are adaptive, or the
>supposedly shared traits are not really the same traits.
>
>The peace of God be with you.
>
>Stanley Friesen
The traditional view has it that Homo sapiens left Africa a little over
100,000 years ago. However, Homo erectus had left Africa already at
least a million years ago. The flow of Homo erectus seemed to have
stopped 700,000 years ago, when the ice ages became more severe. It
seems evident that Homo sapiens went north-east to nowadays China,
which it reached about 60,000 years ago. From there they continued to
Australia most probably 50,000 years ago.
It seems also evident that at this point Homo sapiens had replaced Homo
erectus in Africa, in most parts of Asia and Australia. Europe was
habitated by Homo neanderthalensis, and America was still without human
population. But at that point, 50,000 years ago, it is very possible
that there were places in Asia, islands most probably, and possibly
also in Africa, where there still lived Homo erectus. If the latest
Homo erectus people found thus far lived some 250,000 years ago, it's
no proof that there would not be far more later populations. Maybe they
were small, maybe they were at remote places. Java some 40,000 years
ago would just be a case in point. Remember that Neanderthals lived in
Europe at the same time.
So I think there is no reason to modify the Out of Africa theory. Homo
erectus was replaced from about 300,000 to 30,000 years ago by Homo
sapiens both in Africa and Asia. The replacement seems not to have
included any gene flow, just conquer of a niche by a more able species
of Homo.
The article "Latest Homo erectus of Java" by C. C. Swisher III et al.
in Science 374, 13 Dec 1996, is very profound and careful in its
Uranium/Thorium analysis. U/Th has previously showed evidence of being
a fairly accurate chronometer and in this case it has been used very
carefully and very knowingly.
So I think we have now a more accurate and believable Out of Africa
theory. I don't think that there is anything specially sensational or
odd in the Java case. Interesting and challenging it is.
Timo
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