Heino Prinz <[email hidden]> wrote in news:bm99k7$2vo9$1
@darwin.ediacara.org:
Quoted message said:Makoto Taniguchi said: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
