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Author Topic:   Multi-regionalism and Probability
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 7 of 30 (387723)
03-02-2007 7:58 AM
Reply to: Message 4 by Jon
03-02-2007 2:12 AM


OOH or MRH?
Out of Africa:
The Out of Africa hypothesis (OOA) states that H. sapiens evolved in Africa about 100,000 years ago, and then migrated outward to where populations of H. erectus and H. neandertalensis were living.
Each having separately evolved in Africa an migrated out.
Multi-regional:
The Multi-regional hypothesis (MH) states that after H. erectus, H. neandertalensis, etc. moved from Africa, their populations, though separated, continued to interact and breed.
And that Homo sapiens features evolved in several different locations.
Evidence for MH comes from the "ginger gene",
quote:
Dr Rosalind Harding, of the Institute of Molecular Medicine at the John Radcliffe Hospital, in Oxford, calculated the age of the ginger version of the gene, known as the melanocortin 1 receptor (MC1R), by using a complex model that looked at its mutation rate.
"The gene is certainly older than 50,000 years and it could be as old as 100,000 years," she said.
Because a mathematical model says so? One assuming a constant rate of selection of mutations even though we KNOW this is false? All that is needed is sexual selection for red hair for it to have a higher selection rate.
See Human - Chimp split 4 million years ago? for more on this difference in rates.
... and fossil similarities between regional skull characteristics, especially those found in Asian H. erectus populations and modern populations.
See http://www.dmanisi.org.ge/index.html
http://www.dmanisi.org.ge/paleoanthropology.htm
quote:
The Dmanisi hominid remains are the first hominids discovered outside of Africa to show clear affinities to African H. ergaster rather than to more typical Asian H. erectus or to any European hominid.
Mandible D-211, is different from all known Homo erectus specimens, but at the same time displays a certain similarity to several African fossils from Koobi Fora and Ileret (e.g., ER 992, and ER 730).
Cranial shape is similar in both specimens, spheroidal in superior view and relatively low and angular in lateral view . Greatest cranial breadth is low at the level of the well-pneumatized mastoid processes. The occipitals are relatively narrow and angular.
The combination of the features of the Dmanisi hominids appear more similar to H. ergaster than to H. erectus sensu stricto (or to any of the habilines). This conclusion is consistent with our studies of the Dmanisi mandible . We thus assign the Dmanisi hominids to Homo ex gr. ergaster.
more later ...
ps -- Good start. Nice summary of the positions so far. You'll need more evidence pro and con to flesh it out eh?
One of the arguments for OOH is the modern H.sap. in ethiopia:
http://www.berkeley.edu/.../releases/2003/06/11_idaltu.shtml
quote:
Because the Herto fossils represent a transition between more primitive hominids from Africa and modern humans, they provide strong support for the hypothesis that modern humans evolved in Africa and subsequently spread into Eurasia. This hypothesis goes against the theory that modern humans arose in many areas of Europe, Asia and Africa from other hominids who had migrated out of Africa at a much earlier time.
Enjoy.
Edited by RAZD, : ps added

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This message is a reply to:
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RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 13 of 30 (387812)
03-02-2007 7:35 PM
Reply to: Message 8 by kuresu
03-02-2007 2:20 PM


Re: Ahem :: Clearing up Some Points
H. sapiens fossil located? The oldest cro-magnon fossil
Cro Magnon = Homo sapiens
The oldest Homo sapiens fossil (so far) is the set in Ethiopia:
http://www.berkeley.edu/.../releases/2003/06/11_idaltu.shtml
quote:
160,000-year-old fossilized skulls uncovered in Ethiopia are oldest anatomically modern humans
To show the asian link to Homo erectus would only require that Homo erectus and Homo sapiens interbreed - neander would not be necessary.
http://www.dmanisi.org.ge/index.html
quote:
The Dmanisi hominid remains are the first hominids discovered outside of Africa to show clear affinities to African H. ergaster rather than to more typical Asian H. erectus or to any European hominid.
But H. ergaster is considered ancestral to or an archaic H. erectus
Looking at the typical chart of human development from
http://www.mnh.si.edu/anthro/humanorigins/ha/a_tree.html
or
http://www.handprint.com/LS/ANC/evol.html
we see H. ergaster as the common ancestor to both H. erectus and H. heidelbergensis which is then a common ancestor to H. sapiens and H. neanderthalensis
This makes interspecies hybrids between H. sapiens and H. neander. much more likely to be viable that interspecies hybrids between H. sapiens and H. erectus.
Then we have the genetic data
Just a moment...
quote:
The date of divergence between the mtDNAs of the Neandertal and contemporary humans is estimated to 465,000 years before the present, with confidence limits of 317,000 and 741,000 years. Taken together, the results support the concept that the Neandertal mtDNA evolved separately from that of modern humans for a substantial amount of time and lends no support to the idea that they contributed mtDNA to contemporary modern humans.
Did this multiple-region speciation event occur simultaneously? How can you tell? If they didn't, how can you tell that it isn't just H. sapiens replacing the elder species?
More to the point, there should be genetic evidence of mixing of genes between H. sapiens and other species, evidence that is to date lacking.

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we are limited in our ability to understand
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RebelAAmericanOZen[Deist
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This message is a reply to:
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