Re: DISCOVER/Neanderthal/Homo Sap.
H. M. Hubey (hubey@pegasus.montclair.edu)
4 Sep 1995 13:35:05 -0400
ghanenbu@inter.nl.net (Gerrit Hanenburg) writes:
>Neanderthal.I think we can,by comparing the differences between Neanderthals
>and modern humans with those between other "wildtype" species.We shouldn't
>compare them with the domestic dog but with a natural species cluster such as
>that of the Cape fox,red fox,fennec fox,kit fox and Artic fox (all full
>species) because we may assume that these species have been subject to the
>same proces of natural selection as Neanderthals and early modern humans.
>(even better of course is to compare them with other primate groups)
Why should we care about "paleontological species".
In the end, what we want to know is if the Neandertals belonged
to the same human species and if the modern Europoids are
descended from both the Cro-magnon (African-modern) and Neandertal.
The evidence points more and more to mixing. The only that keeps
the old ideas alive is that the first thoughts on the Neanderthals
set a trend which keeps leaving its residue behind no matter what
new finds point in the opposite direction.
>The speeding up of the process may also be of great importance for it may be
>this that leads to uncoupling of morphological change and speciation (i.e.the
>establishment of reproductive isolation).It's conceivable that morphology is
>more subject to change under artificial selection while the processes that
>may lead to reproductive isolation are less so.(they may have a more random
>character. e.g.in one instance only one major event like a chromosomal
>inversion may be enough for genetic incompatibility while in another case the
>cumulation of several genetic events is required.Artificial selection may not
>have any influence on this).
Well, I don't know if it was you that started this specific thought
but I'm still not clear as to what you mean.
The genetic drift is what would be called "noise" in the framework
of communication theory or mathematical treatments of deterministic
laws corrupted with random/stochastic changes which we cannot explain
but rather simply add to the model.
The "genetic drift" is noise added to deterministic dynamical laws
determining evolution. All I can see is that what you seem to be
implying is that artificial selection speeds up evolution (and
maybe even more). Let's see if this is what you are saying:
Suppose via artificial selection we produce breeds A,B,C....Z of
a particular species. Then we discover to our surprise that they
can all interbreed except A and Z. Then a really nasty guy comes
along and kills off B,C,...Y. Now we only have A and Z left, but
they can't interbreed; so now we have two species from one. Are
you implying that this is "the" mechanism of evolution and that
the Neanderthals split from the rest of the "humanoids" such
a long time ago that they could not have interbred with the arrivals
from Africa?
--
Regards, Mark
http://www.smns.montclair.edu/~hubey
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