Without melanin the skin would be extremely vulnerable to the ravages of the sun. The more melanin in the skin, the more it reflects the harmful rays of the sun, reducing the risk of skin cancer and guarding against the aging process which is characterized by deep wrinkles and age spots. The majority of Vitamin D needed by the body to develop strong bones is absorbed from the sun, so fortunately, melanin does not completely shield the body from the sun's ultraviolet radiation.
Because melanin spreads unevenly over the body, outer sides of limbs are darker than inner ones. Skin with more melanin is more likely to "break out" with a rash or pimple, creating dark spots on the skin, or it may develop moles or large, unattractive scars, called keloids. A decrease in pigmentation may occur when there is trauma to the skin, such as a burn, and the skin has white patches instead of dark ones. The discolorations fade slowly and may create anxiety or stress.
The same melanin that everyone produces separates "races" and creates emotional scars. While very few studies have been done to determine the impact of discrimination over a long period of time, the Committee on National Statistics has identified three primary ways through which racial discrimination might collectively affect people of color. One is "across generations," where lack of opportunities in one generation diminishes opportunities for later generations. Another is "across processes within a domain," where discrimination against a person at an early age may affect later outcomes. The last one is "across domains," where lack of opportunities in one area is based on occurrences in another area.
According to the article, "The Biology of Race," the division of the races, based on skin color, is a sociological classification with no genetic significance. Although the amount of melanin in the skin is determined by the genes inherited from parents, race is attributed more to geography than to genetics. A blend of peoples from different parts of the world created the different "races." Mountains, oceans and deserts created physical barriers which affected the climate, causing some regions to have more direct exposure to the sun. In these regions skin pigmentation became darker to protect itself from the sun.