Human skin color

Human skin color is the visible pigmentation of skin, shaped chiefly by melanin and influenced by genetics, ultraviolet exposure, blood flow, and other factors.

Melanin: A group of pigments that absorb ultraviolet and visible light and contribute color to skin, hair, and eyes. Its amount and type account for much of the variation in skin pigmentation.
Human evolution: The evolutionary history of humans and their lineage since divergence from other apes. Skin pigmentation variation arose during the broader history of human adaptation.
Human skin: The body's outer organ, composed mainly of the epidermis and dermis. Pigment and blood vessels in its layers determine much of its visible color.
Photoprotection: Measures that reduce damage to skin from ultraviolet radiation. Melanin provides partial natural protection, while additional protection can reduce ultraviolet injury.
Race: A socially constructed system of categorizing people, often based on perceived ancestry and physical traits. Skin color is sometimes used to classify race, but the two are not equivalent.
Melanocyte: A pigment-producing cell that synthesizes melanin and transfers it to neighboring cells. These cells make the pigment underlying most persistent differences in skin tone.
Evolution of human skin pigmentation: The evolutionary change in human pigmentation associated with migration and ultraviolet environments. It connects present-day variation to natural selection across ancestral environments.
Ultraviolet: Electromagnetic radiation with wavelengths shorter than visible light and longer than X-rays. Exposure stimulates pigmentation and also creates evolutionary pressures on skin.
Tanning: Darkening of skin after ultraviolet exposure through increased or redistributed pigmentation. It is a visible, acquired change in skin color driven by exposure.
Albinism: A group of inherited conditions involving reduced or absent melanin production. It shows how impaired pigment production differs from ordinary variation in skin tone.

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