The Spectrum of the Colors of Skin: Why Do Humans Have Variations in Skin Color?
In a world where we are separated by race, origin, skin or personality, are we really all that different? The answer to this question begins with the origins for our skin color, which can be traced back through the millennia. We are really not all that different, and if we look at the scientific data behind skin color we will discover why we shouldn’t have conflicts in our society due to prejudice.
To understand why humans have a broad spectrum of skin colors, people must understand Charles Darwin’s Theory of Evolution. Charles Darwin, a biologist, went on an expedition to the Galapagos Islands and later developed a theory that species are formed by adaptations made by earlier species. Over time, species made adaptations to their environment to help them survive environmental changes using natural selection. Natural selection is what isolates those who could or couldn’t survive the changing environment. (Bradley, 39) So using his studies, Darwin came up with a theory that humans were derived from adaptations made by anthropoids and apes. This relates to skin because our skin color today originated as a mutation made by our ancestors in order to survive in a changing environment.
Many scientists believe the sun plays a vital role in our skin color. Many years before the adaptations to our skin were made, our primal ancestors had a lot more body hair than we do today. As time went on, the amount of body hair went down, which exposed more of our skin to the sun. Even though the lack of hair made perspiration more effective, due to newly-made sweat glands, those near the equator were in great danger of strong exposure to the sun’s ultraviolet (UV) rays. To prevent the harmful effects of these rays, human bodies, over time, adapted by adding melanin to the skin. Melanin is the human body’s natural sunscreen. Also, melanin is the pigment in skin that makes peoples’ skin darker. (“Human Skin Color Variation”) Why does the human body need to prevent excess UV rays from itself? Too much exposure to sun can cause skin cancer. In addition, it can strip the body of folic acid, which may result in unhealthy fetuses. (“Human Skin Color Variation”) It also can cause premature aging, freckles, wrinkles, mottled pigmentation, and many other damaging factors to human skin. (“Cosmetic Procedures: Sun Exposure and Skin Cancer”) So, people nowadays have darker skin due to their ancestors staying in warmer climates and retaining their melanin.
This explains the origins of dark skin, however how did people get light skin? Scientists believe that the ancestors of people with light skin moved away from Africa to regions of the Earth where UV levels were lower. This means that their bodies needed more UV rays for their bodies to absorb. It’s confusing, but our bodies need a delicate balance of UV. UV helps our bodies create vitamin D, which helps calcium to be absorbed into our bones, making them more durable. However, too little UV can cause foliate deficiency (lack of folic acid in the body). Such a deficiency causes different severities of birth defects, such as “neural tube defects” (Jablonski, 60) which are “defects of the brain and spinal cord” (NTD’s). And too much UV can have a damaging effect on the human body. So, lighter skin helps the body absorb UV due to less melanin to block it out. (“Human Skin Color Variation”) Our ancestors that moved to regions away from the equator adapted to the decrease in UV rays by making our skin lighter. This trait got passed on from ancestor to ancestor all the way to the present descendants causing a diversity of light skin tones.
Another factor that affects skin color is that even though some of our ancestors moved north, they still retained their dark skin. How is this possible? The natives who lived in coastal areas, such as the native people of parts of Canada and Alaska, had more access to vitamin D due to their diet, which was high in seafood. This meant the body didn’t have to adapt by changing skin color. The body was already getting an alternative source of vitamin D, lessening the need for vitamin D being absorbed through the skin. Also, another contributing factor to the natives’ dark skin is that they were living in icy regions. The UV rays that were hitting the Earth were being reflected back onto the natives causing them to be exposed to the sun and resulting in a rise of melanin. So those with native ancestors from Alaska and Canada would tend to have a darker-pigmented skin. (“Human Skin Color Variation”)
Over the course of generations of mutations and variations of our genetic coding, it has given the world a really diversified population. Yet, society struggles with racism and prejudices. And many of these false judgments are based on our appearance, our clothing, and mostly our skin color. Many have lost their lives due to racial tension. The lynching of African-Americans by the Ku Klux Klan in the 1900s, the violent actions of the L.A. Riots in 1992, and the backlash directed at people of Middle-Eastern ethnicity post-9/11 are all examples of how appearances can lead people to inflict harm on the innocent. But they should all know that we humans are really much alike. Our DNA is 99.99% the same as everybody else’s. (Highfield) How? It’s because our ancestors all originated from Africa. So are we really that different? Are we different because our ancestors dispersed all around the world? Think about that the next time you judge someone based on the way they look.
Bradley, James V. “How Species Change” New York: Infobase Publishing, 2006.
“Cosmetic Procedures: Sun Exposure and Skin Cancer.” American Academy of Dermatology.
WebMD (2012) 1-3. 6 Nov. 2012.
Highfield, Roger. “DNA Survey Finds All Humans Are 99.9pc the Same.” The Telegraph. 20
Dec. 2002. Web. 20 November 2012.
“Human Skin Color Variation.” Smithsonian Museum of Natural History. Web. 29 October
Jablonski, Nina G. Skin: A Natural History. Berkeley, California: University of California Press,
“Neural Tube Defects (NTDs).” National Institute of Health. Web. 24 May 2007. 16