Human skin color is primarily due to the presence of melanin in the skin. Skin color ranges from almost black to white with a pinkish tinge due to blood vessels underneath. Variation in natural skin color is mainly due to genetics, although the evolutionary causes are not completely certain. According to scientific studies, natural human skin color diversity within populations is highest in Sub-Saharan African populations, with skin reflectance values ranging from 19 to 46 (med. 31) compared with European and East Asian populations which have skin reflectance values of 62 to 69 and 50 to 59 respectively. The term "range" is loosely defined in this case, as African albinos have obviously not been taken into consideration when calculating the "range".
The natural skin color can be darkened as a result of tanning due to exposure to sunlight. The leading theory is that skin color adapts to intense sunlight irradiation to provide partial protection against the ultraviolet fraction which produces damage and thus mutations in the DNA of the skin cells. Other factors that can modify skin color include protection from ambient temperature, infections, skin cancer or frostbite, an alteration in food, and sexual selection.
The social significance of differences in skin color has varied across cultures and over time, as demonstrated with regard to social status and racism.
Read more about Human Skin Color: Melanin and Genes, Evolution of Skin Color, Irregular Pigmentation, Exposure To Sun, Geographic Variation, Social Status and Racism
Famous quotes containing the words human, skin and/or color:
“Alas! how little does the memory of these human inhabitants enhance the beauty of the landscape!”
—Henry David Thoreau (1817–1862)
“Moses came down from Mount Sinai. As he came down from the mountain with the two tablets of the covenant in his hand, Moses did not know that the skin of his face shone because he had been talking with God.”
—Bible: Hebrew, Exodus 34:29.
“For the profit of travel: in the first place, you get rid of a few prejudices.... The prejudiced against color finds several hundred millions of people of all shades of color, and all degrees of intellect, rank, and social worth, generals, judges, priests, and kings, and learns to give up his foolish prejudice.”
—Herman Melville (1819–1891)