Skin Color Evolution

The human body, just like animals, has evolved over time. One of the greatest biological adaptations of the humans is skin color. Today, there are 7 billion different skin tones since no skin color is identical. However, in Africa, 100 thousand years ago that was certainly not the case.[Bryce] The evolution of skin color over the past 100 thousand years is due to the combination of three factors: skin exposure, ultraviolet rays, and Vitamin D. [Jablonski and Chaplin] These factors attribute to the wide spectrum of skin colors seen across the globe and explains why in Senegal, Africa there are some of the darkest skin pigments, but just 2700 miles north in Ireland, the palest skin pigments can be observed. While many of the biological adaptations …show more content…
[Jablonski and Chaplin] The cline of human skin pigmentation is caused by strength of ultraviolet rays that is based on its latitude on the globe. Particularly in lower latitude areas, the ultraviolet rays are more intense. [Jablonski 1] This explains why in places like Senegal, Africa, where some of the darkest skin colors can be seen. While as one moves higher in latitude towards the poles, the less intense the ultraviolet ray’s radiation is. The people of Ireland are a testament to this as they have some of the fairest and lightest skin pigments seen across the world. Ultraviolet radiation acts as a selective force in the evolution of human skin color and human bodies fronted a defense in the form of pigmentation. [Roy] Consequently, ultraviolet radiation, shortwave ultraviolet radiation specifically, is the main catalyst in the metabolism of Vitamin D, and for that reason there is a high concentration of Vitamin D in darker skin and a lower concentration in lighter skin. [Jablonski 2] Vitamin D’s main functionality in the human body is calcium absorption. [Jablonksi 2] While Vitamin D does not play a direct role in the color of skin, but it does have many survival benefits which explains why nature selected it as a biological adaptation for humans. Vitamin D’s benefits include maintaining healthy heart function, stabilizing the nervous system, and prevent a wide variety of cancers. [O’Neil] Vitamin D is an effective tool that would help any organism, in this case humans, reproduce a healthy and viable offspring for the next generation. [Roy] However, for there to be sufficient amounts of Vitamin D, the skin must be exposed to an enough shortwave ultraviolet radiation, and because of this dark skin becomes a necessity for its