Heino Prinz  wrote in news:bm99k7$2vo9$1
{at}darwin.ediacara.org:

> Makoto Taniguchi wrote:
>> I was wondering, since Asia and Europe is extremely close together,
>> why did they evolve in a different manner? the ice age theory might
>> explain it but when you really think about it, mongoloids probably
>> lived through the ice age in the same kind of climate as the
>> caucasoids hence the lighter skin colour compared to negroids but,
>> mongoloids developed a different eyelid shape to protect them from the
>> cold but did the caucasoids? no. The Caucasoids developed different
>> hair colours and eye colours but did the mongoloids? no.
>> 
>> The climate and the area of both the mongoloids and caucasoids are not
>> that different. So why did we evolve in a different manner?
>> 
> Chance. At least for the causcasoid it had been shown (by genetic 
> methods) that the population had decreased considerably probably about 
> 8000 years ago. (Is the population figure of <1000 correct?) Now one or 
> a few chance mutations had a big impact on such a small population. 
> Certainly, if the mongoloid eyelid shape would have developed there, it 
> would have been maintained by natural selection.

I can accept that the difference is chance, but I can also believe that 
there is an adaptive explanation. In terms of overall pigmentation 
levels, Chinese are similar to Italians, and you will note that northern 
China is at the same latitude as Italy. The blonde and blue-eyed northern 
europeans live at a much higher latitude (OK there are eskimos, but how 
long have they lived at the high latitude?). There is by the way much 
debate on this issue. 

With regard to eyelid shape, I can envision an explanation based on 
windiness, with the forests in Scandinavia preventing the need, and the 
steppes in Mongolia leading to high wind chills and the need for the 
fold. Since I have no data on either current or historical average wind 
speeds in the two regions, and since even if there was a difference the 
mongoloid eyelid might still have been an advantage in northern Europe, I  
wouldn't bet a lot of money on my explanation. But it is always fun to 
try to come up with a good just-so story. 

Yours,

Bill Morse
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