Over time, we should expect a fair bit of evolutionary divergence between Mars settlers and the human population on Earth, according to Rice University biologist Scott Solomon, who examined this possibility in his 2016 book Future Humans: Inside the Science of Our Continuing Evolution.
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The Red Planet is much smaller; the force of gravity on its surface is just 38 percent of the pull we feel here on Earth. Mars also lacks a global magnetic field, a thick atmosphere (though we could remedy that with terraforming), and a protective ozone layer. Mars gets hammered a lot harder than we do by space radiation.
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What sorts of changes could we see over there? Well, for one thing, natural selection might adjust skin tone on the Red Planet, to help settlers cope with that serious radiation load.
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This may lead to dark skin due to increased production of melanin, just as we see among some peoples here on Earth. But other pigments could potentially be pressed into service as well, including carotenoids, the molecules that give real carrots — as opposed to those purple artisanal weirdos — their color, according to Solomon.
Read full, original post: Orange Skin, Thick Bones, and All the Other Ways the Human Body Could Change on Mars
