There wasn’t an event that triggered the evolution of humans Into the four main groups (and countless minor groups). Genetic drift over time, with geographic separation between the groups, actually explains the diversity pretty well.
Also, recall that recent findings have shown that non-African homo sapiens interbred with homo neandertalis. That interbreeding would have added a LOT of genetic differences, especially at the low population numbers of the time. On top of that, you have genetic drift and radically different climates.
Me, I’m for language arising in either the Indus region or Mesopotamia. Both were early cradles of civilization, and the agrarian lifestyle would have required a broader vocabulary than a hunting lifestyle.
There wasn’t an event that triggered the evolution of humans
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Let’s not count the eruption of Mt. Toba in 72,000 BC, which decimated the human population at the time ...
This could erupt into a robust sub-thread. :’)
Caucasians and Mongoloids live in the same latitude. Supposedly environment is the cause of evolutionary drift. Cold is supposed to lead to prominent (European) noses. Why don't the Asians have prominent noses. It snows there too. Their noses are more like African noses, the noses of a hot climate. Another problem I have with genetic (evolutionary) drift is pigmentation. Asians are darker than whites, yet they get about the same amount of sunlight, the supposed cause of melanin which colors the skin. Somehow I think the evolutionary process, genetic drift, and an out of Africa theory needs more work.
The drift between the major races is great. The apparent time span is equally great. The idea that the races were isolated for such a long time troubles me. I would expect that the nomadic life of early man would have led to greater intermingling among the races, especially in Eurasia, and a more blended result.