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”?

36 points
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Yeah, depending on what you consider “new”.

  • Nose shapes to account for dryer air on Africa and middle east.
  • Nose shapes to account for colder weather.
  • There are a group of people that have larger spleens to make them able to drive dive for longer periods (Bajau People).
  • “Asian” eye-shape, afaik, is an adaptation to protect the eyes from sand.

The list is actually very long.

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25 points

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

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19 points

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.

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8 points

Yeah, I think you’re right (on both counts unfortunately, but that’s evolution for you).

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2 points

Or, enough protection that you live long enough to reproduce before dying a terrible, agonizing death.

I think it’s protective when you have one copy of the gene, and detrimental when you have two copies. Unfortunately, malaria was a strong enough pressure that the sickle cell gene was selected for, up to a certain percentage of the gene pool.

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3 points

Cool! Do you know any sources where I can read more about it?

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1 point

Is there much sand in Asia?

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2 points
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The Middle East and the Gobi desert come to mind. Asia is pretty big.

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1 point

Middle easterners don’t have Asian eyes though.

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28 points
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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.

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5 points

I’ve read that people in Colorado have far more blood carrying capacity from the high altitude. Seems something one can develop.

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3 points

Super cool, thanks!

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18 points

Less than 5000 years ago, northern europeans developing a genetic mutation that allowed them to digest cow’s milk.

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3 points

But then how do other non-European groups like Middle Easterners and Asians drink it normally? Did they independently evolve the same mutation?

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12 points

Fermentation (kefir, yoghurt, cheese). Recently lactase.

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7 points

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.

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9 points

Read what turned out to be a fairly racist article back in the day, about the differences in blacks and whites.

One thing that rang true was hair types. When wet, kinky hair sheds heat more easily and flat hair is insulating. Anyone know if this is true?

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7 points

I learned in a university course that kinky hair holds sweat better and allows for better cooling. Where straight, greasy hair drips it off faster.

Another interesting environmental trait is sickle cell because it can prevent or at least lessen malaria.

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6 points

I don’t think epicanthic folds would be considered evolution. Most human changes are in our immune system and sense of smell.

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6 points

Interesting, can you recommend some reads about it?

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