If too much exposure to the sun causes cancer, how are there still any fair-skinned people on earth? For the vast majority of human history, we didn’t have sunblock. Shouldn’t we gingers be extinct by now?
In: Biology
There is evidence that our ancestors started to wear clothes as far back as 100,000 to 500,000 years ago so it might predate the modern human species. The evolution to lighter skin is likely in the last 50000 years so it did not happen when we did not have a way to protect us from the sun. Clothes are a very good sunblock.
Modern human species is around 200,000 years old so for the majority of humans the skin for all was dark.
The skin color depends on evolutionary skin exposure. if you get to little UV light in your skin you produce too little Vitamine D.
Too much UV and it will break down Folate that is very important during pregnancy. So the skin color evolve towards a point where you get enough of both
For a human with dark skin, the children tend to be paler than adult likely as a way to get more Vitamine D when you grow and more Folate when you are pregnant.
Rickets is what you can get wit to low Vitamine D levels. You hade a lot of it in UK primary during the industrial revolution when in some periods 80% of children in London had it when so much of the sunlight was blocked by smog and fog. It can today be solved by supplementing Vitamine D.
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