RE: mtDNA Eve and the determination of humanity

From: Dick Fischer <dickfischer@verizon.net>
Date: Sat Feb 25 2006 - 13:46:41 EST

Hey Guys and Gals:
 
Before we jump from one horse to the other, we need to look at the horse
we want to ride. According to Donald Johanson (Remember, Lucy?), the
Multiregional Continuity model (MRH) has the following characteristics.
 
The Multiregional Continuity Model15 contends that after Homo erectus
left Africa and dispersed into other portions of the Old World, regional
populations slowly evolved into modern humans. This model contains the
following components:
* some level of gene flow between geographically separated
populations prevented speciation, after the dispersal
* all living humans derive from the species Homo erectus that left
Africa nearly two million-years-ago
* natural selection in regional populations, ever since their
original dispersal, is responsible for the regional variants (sometimes
called races) we see today
* the emergence of Homo sapiens was not restricted to any one
area, but was a phenomenon that occurred throughout the entire
geographic range where humans lived
Now the counter intuitive part is the idea that H erectus in Europe and
H erectus in Africa developed in situ to become H sapiens in both
locations. This would be like putting zebras in Australia and zebras in
Africa and a million years later finding horses grazing on both
continents with only fossils of zebras to be found. And this ignores
the second wave out of Africa that occurred around 100,000 years ago
with both displacement and interbreeding combined.
 
So let's take another look at the Out of Africa approach. Again,
quoting Johanson:
 
In contrast, the Out of Africa Model asserts that modern humans evolved
relatively recently in Africa, migrated into Eurasia and replaced all
populations which had descended from Homo erectus. Critical to this
model are the following tenets:
* after Homo erectus migrated out of Africa the different
populations became reproductively isolated, evolving independently, and
in some cases like the Neanderthals, into separate species
* Homo sapiens arose in one place, probably Africa (geographically
this includes the Middle East)
* Homo sapiens ultimately migrated out of Africa and replaced all
other human populations, without interbreeding
* modern human variation is a relatively recent phenomenon
Aha, here is the fly in the ointment. Thanks to Templeton we know there
was interbreeding. Egad! Are there logical inconsistencies in both
arguments? Is it going to be left up to ASA to solve this one? Mouses
at the ready . Get set . Click!
 
http://www.actionbioscience.org/evolution/johanson.html#Primer
 
Dick Fischer
~Dick Fischer~ Genesis Proclaimed Association
Finding Harmony in Bible, Science, and History
 <http://www.genesisproclaimed.org> www.genesisproclaimed.org
Received on Sat Feb 25 13:47:05 2006

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