According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.
Human beings are no exception to biological evolution. Like other organisms around the world, humans have significantly changed overtime and have developed all sorts of diverse characteristics. One noticeable characteristic of human beings is the variation of skin color. Skin color has been used to identify, classify, and verify the variation that exists in the human population around the world. How did such a distinct variation arise and how did it play into adaptation?
I’ve often heard that “humans came from monkeys,” or something similar. It is true that humans’ ancestors were primates, who first resided in warm and sunny Africa; they had similar features to today’s apes, such as a hairy body. The purpose of the vast amount of hair was to protect the body from the sun’s ultraviolet (UV) rays and to prevent overheating, mainly by acting as a barrier for the skin underneath the hair (Jablonski, 598). Some parts of the body such as palms were not covered with hair, but with sweat glands. Sweat glands allowed the body to cool off via evaporation at the surface of the skin; sweat glands were more efficient at thermoregulation. Overtime, early humans with a high amount of sweat glands were selected for since they had the best method at the time to keep themselves cool in warm environments (Kirchweger). This meant that overtime, humans lost most of their hair on their bodies, leaving their skin exposed. Sweat glands were going to help the body to cool down, but they couldn’t protect the skin from harmful UV rays. This is where melanin worked its magic, and it’s the reason for the diversity in skin color today.
Melanin helps reduce the absorption of wavelengths into the skin (Chaplin, Jablonski, 59). The more melanin in the skin, the greater the protection against harmful UV rays, and the amount of melanin in the skin correlates with the skin’s color (more melanin means darker skin). Because Africa was a very warm climate that received lots of sunlight, humans went from having thick fur-like hair to almost hairless, dark skin in order to protect them from detrimental effects of UV rays. However, like humans today, the ancestors of modern humans did not stay in one place and various groups moved to various regions of the world. Moving to new regions meant coping and adapting to a new environment.
Geographical isolation in the past has caused a variation in skin color; natural selection selected specific skin pigments depending on environmental factors. Early humans who...