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:
“We can imagine a society in which no one could survive as a social being because it does not correspond to biologically determined perceptions and human social needs. For historical reasons, existing societies might have such properties, leading to various forms of pathology.”
—Noam Chomsky (b. 1928)
“Her skin was white as leprosy,
The nightmare Life-in-Death was she,
Who thicks man’s blood with cold.”
—Samuel Taylor Coleridge (1772–1834)
“‘Twas mercy brought me from my Pagan land,
Taught my benighted soul to understand
That there’s a God, that there’s a Saviour too:
Once I redemption neither sought nor knew.
Some view our sable race with scornful eye,
“Their color is a diabolic die.”
Remember, Christians, Negroes, black as Cain,
May be refin’d, and join th’ angelic train.”
—Phillis Wheatley (c. 1753–1784)