Human skin color

Human skin color, also known as skin tone, ranges from the darkest brown to the lightest hues. Differences in skin color among individuals are caused by variation in pigmentation, which is largely due to genetics (inherited from one's biological parents), and, in adults in particular, to exposure to the sun, disorders, or some combination thereof. Differences across populations evolved through natural selection and sexual selection, because of social norms and differences in environment, as well as regulation of the biochemical effects of ultraviolet radiation penetrating the skin.

From Wikipedia, under CC BY-SA. More on occurri.