Are there other human traits like light skin which people developed to adapt to the "new" environment they settled in?
I'm referring to the human race evolving in the African continent and then migrating to the rest of the world.
Evolving in Europe made people light skinned to account for the reduction in sunlight exposure, are there any other traits which other ethnicities developed to adapt to their new environment?
Or are the diifferent traits in different ethnicities just stuff that developed by chance and got somehow reinforced because of the isolation between populations?
This question came to my mind first thinking about "Asian eyes", do they serve any "purpose"?
There's also sickle cell anemia: IIRC it protects against something like the tse-tse fly or mosquito borne illnesses native to parts of the African continent
I believe that it offers a degree of protection against malaria. Or, enough protection that you live long enough to reproduce before dying a terrible, agonizing death.
One more is that some people in the Himalayas (Nepalese, Tibetans, etc.) have some pretty recent adaptations for living at extremely high altitudes where there’s less oxygen. This Wikipedia article has more examples of recent adaptations:
https://en.m.wikipedia.org/wiki/Recent_human_evolution
Another interesting factoid is that Africa has more genetic diversity than the rest of the world. So, don’t sleep on the fact that that Homo sapiens spent more time radiating throughout Africa than radiating out of Africa.
I’m no expert but I think it’s a mutation that still isn’t universal i.e. there is still a very large lactose-intolerant population in east-asia, which is also reflected in their cuisine.
I read the question as a difference of traits rather than whole new traits, if that makes any sense.
So my suggestion was that the strength of sexual dimorphism varies. That is, some ethnicities may have a very significant difference in appearance between sexes, but in other ethnicities the difference would be lessened.