[Redcloak]

Another case in point would be the appearance of Asians. When I was a boy, it was taught that they developed narrower eyes to protect their vision as they crossed the Gobi desert into China. Geneticists now know that the genes giving them their distinctive appearance developed after they'd reached what's now China. (Only ~14,000 years ago) Thus the gene didn't spread as a result of environmental pressure, but rather because of aesthetics. (Also, IIRC, the Gobi desert wasn't a desert when their ancestors would have crossed!)

[blam]

"When I was a boy, it was taught that they developed narrower eyes to protect their vision as they crossed the Gobi desert into China. "

The distinctiness of the Chinese are a mystery to me. However, I do know that as recent as 2,000 years ago, all the people to the north and east of the Gogi Desert were Caucasians. The Great Wall of China was built to keep out these Caucasian people with names like, Xiongnu, Saka, Yuezhi, Sogdian and many others. There are many poems lamenting the green eyes of the Han Emperors.

The Curse Of The Red-Headed Mummy

[Cronos]

Thus the gene didn't spread as a result of environmental pressure, but rather because of aesthetics

Interesting. But you're wrong when you say: Another case in point would be the appearance of Asians

Arabs, Persians, Russians and Indians don't have narrow eyes (but then they aren't Mongoloid, all are Caucasians).

Could it be that the Mongoloid group were the first to move out of Africa (some may have stayed behind as Bushmen -- pure conjecture here), then had a few millenia in which they developed so forming a separate race, while the CAucasians came next and they evolved separately while those who remained behind evolved separately again to become Afroid --- the Afroids would have been separated from the others by the Sahara -- I think the Egyptians were Caucasian, while the Mongoloids would have been separated by Siberia and the Gobi and the Himalayas.