My Question about human evolution under cold climates



M

Makoto Taniguch

Guest
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?
 
R

R.Schenck

Guest
On Wed, 28 Jan 2004 18:36:14 +0000 (UTC), [email protected]
(Makoto Taniguchi) wrote:

>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?

i'd like to venture an answer to this, i've wondered it myself.

I think that ultimately its because they were two different populations under similar conditions,
each with their own set of restrictions. The large nose of 'cacasians' is supposedly to warm air
going itno the body and/or cool the body internally (as opposed to simple exposure) to prevent
sweating. Perhaps 'mongolish' populations found another solution, whatever it may be. Basically the
selection pressures resulted in a different effect in each population; in both the pressure was
'adapt to cold' (well, in so far as that is true itself) rather than 'develop a large cold adapted
nose', and the results were different because the starting material was different.
 
R

R.Schenck

Guest
On Wed, 28 Jan 2004 18:36:14 +0000 (UTC), [email protected]
(Makoto Taniguchi) wrote:

>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?

(my original post hasnt appeared yet and this is an afterthought)

also the ainu in Japan are supposed to have caucasian features, perhaps they are caucasions, and
perhaps they are a subset of asians that just developed in parallel with caucasians. If the first,
then its entirely possible that what appears to be cold adaptations in siberians and inuit are in
fact not and their populations have simply spread out more recently into those territories. If the
second, then it would be a demonstration of the wild variability and plasticity of populations and
organisms.
 
M

Malcolm

Guest
"Makoto Taniguchi" <[email protected]> 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

probably far outweighs thermal efficiency as a survival trait. Eskimo noses

characteristics. (Not sure I really buy this last one, but it has been seriously advanced as
a theory).
 
C

C. P. Weidling

Guest
"R.Schenck" <[email protected]> writes:

> On Wed, 28 Jan 2004 18:36:14 +0000 (UTC), [email protected] (Makoto Taniguchi) wrote:
>
> >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?
>
>
> i'd like to venture an answer to this, i've wondered it myself.
>
> I think that ultimately its because they were two different populations under similar conditions,
> each with their own set of restrictions. The large nose of 'cacasians' is supposedly to warm air
> going itno the body and/or cool the body internally (as opposed to simple exposure) to prevent
> sweating. Perhaps 'mongolish' populations found another solution, whatever it may be. Basically
> the selection pressures resulted in a different effect in each population; in both the pressure
> was 'adapt to cold' (well, in so far as that is true itself) rather than 'develop a large cold
> adapted nose', and the results were different because the starting material was different.

I'm inclined to agree with the basic premise that two separate groups, faced with the same
environmental challenge, may evolve different responses. I watched a documentary a long time ago, in
which people were studying Tibetans to see how they were adapted to high altitude. I've forgotten
the details but as I recall, they did not have some of the adaptions that were characteristic of
Andean Indians, which rather surprised the researchers.

The long nose characteristic is, however, supposed to have developed separately among many
diverse groups in reaction to very dry climates. The nose helps moisterize the air before it
reaches the lungs.
 
M

Makoto Taniguch

Guest
"R.Schenck" <[email protected]> wrote in message news:<[email protected]>...
> On Wed, 28 Jan 2004 18:36:14 +0000 (UTC), [email protected] (Makoto Taniguchi) wrote:
>
> >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?
>
>
> i'd like to venture an answer to this, i've wondered it myself.
>
> I think that ultimately its because they were two different populations under similar conditions,
> each with their own set of restrictions. The large nose of 'cacasians' is supposedly to warm air
> going itno the body and/or cool the body internally (as opposed to simple exposure) to prevent
> sweating. Perhaps 'mongolish' populations found another solution, whatever it may be.

That doesn't sound right at all. If it was simply because of the difference between Mongoloids and
Caucasoids, you really can't explain the physical features of the Native American population.
 
R

R.Schenck

Guest
[email protected] (Makoto Taniguchi) wrote in message news:<[email protected]>...
> "R.Schenck" <[email protected]> wrote in message
> news:<[email protected]>...
> > On Wed, 28 Jan 2004 18:36:14 +0000 (UTC), [email protected] (Makoto Taniguchi) wrote:
> >
> > >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?
> >
> >
> > i'd like to venture an answer to this, i've wondered it myself.
> >
> > I think that ultimately its because they were two different populations under similar
> > conditions, each with their own set of restrictions. The large nose of 'cacasians' is supposedly
> > to warm air going itno the body and/or cool the body internally (as opposed to simple exposure)
> > to prevent sweating. Perhaps 'mongolish' populations found another solution, whatever it may be.
>
> That doesn't sound right at all. If it was simply because of the difference between Mongoloids and
> Caucasoids, you really can't explain the physical features of the Native American population.

but the native am. population is, well, a different population under similar conditions,
complete/replete with its own incumbrances and restrictions to just how they can adapt in reaction
to the environment. So if they appear similar to any group, it might be because they are a different
'system' under the same stress, or if they are very closely related, they might be similar (but
seperate) systems reacting the same way to a similar environment.

perhaps you are trying to see if, since in your estimation (and i am not saying i disagree/agree
with it) the native americans have caucasiod-ish cold adapted features, that they might share a
close relationship. perhaps. but all humans are so inter-related that i don't think that is
necessarily true. The 'native am.' population and the 'caucasiod' population might look equally
different from the 'mongol/siberian' population because the 'mongol/siberian' population is the
one that has changed its 'system'. the other two might not be very closely related, infact the
'native' and 'mongol' pop could infact be very closely related, but the 'system change' (ie
whatever is making them different) is simply not shared (iow, not present in the shared ancestral
population of both).

damnit i hope that wasn't too unclear.