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How did sunlight contribute to the evolution of different human skin colors?

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Homo sapiens Human beings (Homo sapiens) are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning.

The evolution of human skin color is a primary example of natural selection in response to varying levels of ultraviolet (UV) radiation across different latitudes.12

In tropical regions with intense sunlight, populations evolved darker skin tones. Melanin—the pigment responsible for skin color—acts as a protective barrier that absorbs UV radiation, shielding the skin from sunburn and reducing the risk of skin cancer.123

Conversely, as human groups migrated to northern latitudes where sunlight is less intense, selective pressure favored lighter skin. This adaptation was driven by the body's need to synthesize vitamin D, which is produced in the skin through exposure to sunlight. In environments with limited UV light, individuals with lower levels of melanin were better able to produce sufficient vitamin D, preventing conditions like rickets and improving survival and reproductive success. Over thousands of years, these environmental pressures resulted in the global cline of skin pigmentation observed today.12