ELI5; Why is dark skin selected for when you’re in the sun a lot? Dark colors absorbs most visible light, while white reflects it. Is it different for UV light?

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ELI5; Why is dark skin selected for when you’re in the sun a lot? Dark colors absorbs most visible light, while white reflects it. Is it different for UV light?

In: Biology

Because the upper layer of skin is dead anyway. That dead layer of skin absorbs a lot more of the radiation from the Sun than it would if it was lightly colored, which helps protect the skin beneath it. This is white dark skin people don’t get sunburn nearly as easily as fair-skinned people.

Darker-skinned people do technically absorb more heat from the Sun than lighter skin people, but compared to the amount of heat that the body is producing naturally through its own metabolic actions this difference is negligible.

Yes it’s different.

It’s not about adsorbing light it’s about absorbing less uv radiation, which is what dark skin does thanks to the melanin.

Fun fact – Very early humans ancestors were actually light skinned, but then we began developing sweat glans and losing hair to survive.

But obviously the African sun isn’t too kind to fair skin so by the time homo sapiens were around we were all dark skinned.

You get all of your vitamin D in about 7-10 minutes in the sun with no sunscreen. Past that you start to risk burns (UV damage). Eventually darker mutations, which have more melanin to stop the penetration of UV rays, would be selected for as they wouldn’t be in pain often and would have a lower risk of melanoma.