Essay: The Biology and Evolution of Skin Colour, and the Social Impact

As a child, I loved playing outside. I spent my entire summer days outside with my siblings. It didn’t matter if my skin got one or two shades darker, it only mattered that I was having fun. However, growing up, I distinctly remember avoiding going outside because I didn’t want to get sunburnt and I definitely didn’t want to get darker and when I did go outside, I made sure to put a lot of sunscreen. Under those circumstances, I realized I had fallen into a fallacy created by society in which I believed that getting darker was a bad thing. Realizing it now, the true culprit in this wasn’t just the sun, but my actual genetics and the science behind it. It didn’t matter how much I tried avoiding the sun, my skin color is the way it is due to my biological makeup and society has formed a different meaning to it. We live in a world full of color and skin color being one of our most obvious human traits, it has come to influence our social interactions in intricate ways. Today, we will explore the biology and evolution of skin color, then uncover the origins of skin color hierarchy, before finally, understanding its social impact.
There are two major influencing factors on skin color: genetics and the sun. Melanin is the pigment that gives our skin its color. Melanocytes, produce melanin which is stored within small membrane-enclosed organelles called melanosomes that then are transferred to Keratinocytes, the recipient cells for melanin which create the upper layers of the epidermis. Humans have different skin colors because their melanocytes produce different amounts and kinds of melanin, mainly in two forms: eumelanin and pheomelanin. According to Nina Jablonski, a professor in biological anthropology, Eumelanin, which consists of large and dense melanosomes is more abundantly found in darker skin while pheomelanin,which consists of small, thin melanosomes, in found in those with lighter skin, meaning, skin color varies depending the amount and kind of melanin that is produced and the way it is distributed in the skin. Skin color is also influenced through a process driven by the sun. Exposure to sunlight stimulates melanocytes which absorb UV light to produce melanin. Those with lighter skin produce less melanin while those with darker skin produce more. Interestingly enough, that same melanin being produced protects us from the damage that the absorbed UV light can cause. Because of the low production of melanin in light skin, high sun exposure results in sunburns and possibly cancer and although those with darker skin are still susceptible to these effects, their skin offers better protection due to the more abundant production of melanin resulting in a tan rather than sunburn. This explains the skin variation within specific racial groups themselves depending in the region they’re in. For example, African Americans have eumelanin in their genetics which is why they are naturally darker skinned. If they live in a region with high sun exposure, then darker their skin will be, and the less exposure, the lighter. As stated by Sarah Tishkoff, an evolutionary geneticist from the University of Pennsylvania, this undercuts old notions of race. We can’t really use skin color to classify humans, anymore than we use other complex traits like height.The palette of skin color within specific ethnic groups themselves is so diverse, that the question of whether there is such thing as race is put forward.