Lighter-colored eyes and hair evolved somewhere around the Baltic Sea about six thousand years ago. It’s not obvious why. Hair and eye color don’t affect vitamin D metabolism, or anything else physiological come to that, so there seems to be no practical benefit. The supposition is that these traits were selected for as tribal markers or because people found them more attractive. If you have blue or green eyes, it’s not because you have more of those colors in your irises than other people but because you simply have less of other colors. It is the paucity of other pigments that leaves the
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