Yes, there is a correlation between where populations of humans live and the amount of pigment in their skin. This correlation is known as the geographic distribution of human skin color. In general, people who live closer to the equator tend to have darker skin, while those who live farther from the equator tend to have lighter skin. This is because exposure to sunlight affects the amount of melanin, the pigment that gives color to the skin. Sunlight stimulates the production of melanin, which helps protect the skin from UV damage. People who live in areas with high levels of UV radiation, such as the tropics, have evolved to produce more melanin, which provides additional protection against skin damage and skin cancer. Conversely, people who live in areas with lower levels of UV radiation, such as northern latitudes, have evolved to produce less melanin, allowing their skin to absorb more vitamin D from sunlight.
