"Makoto Taniguchi"  wrote in message
>
> I was wondering, why did the Siberian Natives and Inuits develop
> small bodies with a relatively flat face while North American Natives
> (non Inuit) and caucasians develop large bodies with a long nose,
> deepset eyes etc.
>
> If the inuits lived in cold climates like the Natives and the
> caucasians, how come their bodies evolved in a completely different
> way?
>
There are two evolutionary forces, natural selection, made famous by Darwin,
and genetic drift, which isn't generally talked about much by
non-specialists.
Genetic drift is caused by random loss of alleles, and fixation (goes to
100%) of previously rare alleles, purely by chance. It is the more
significant force - for every advantageous mutation there are many neutral
or near-neutral mutations, and even an advantageous mutation has only a 2s
(where s is the fitness advantage) chance of being fixed.

Drift is probably a large part of the real explanation. Another thing your
source hasn't mentioned is the role of the nose as a sexual signal - that
probably far outweighs thermal efficiency as a survival trait. Eskimo noses
are infantilised, whilst Caucasian noses might look like primary sexual
characteristics. (Not sure I really buy this last one, but it has been
seriously advanced as a theory).
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