The Science of Skin Color

Humanity has spread all over the globe. While our origins are in Africa, many of our ancestors left the continent to explore the world, take advantage of new resources, and roam new lands. With the spread of humanity came the need for adaptation to a variety of new environments and climates. We have roamed the earth as a species for 350,000 years. From Morocco to Japan and Argentina to Australia, we have successfully colonized every corner of the earth. But an interesting thing that has come from this global spread, though we are all the same species, we all look a little bit different depending on where you go.

People who live near the equator or in areas with high UV exposure tend to have darker skin. This adaptation is advantageous as it protects the body from UV rays and prevents things like skin cancer.

People from Sub-Saharan Africa and Austronesian populations have the highest quantities of melanin, while people from Northern Europe and Central Asia have the least amount. The darker the skin, the less the sun penetrates; the lighter the skin, the more the sun penetrates. It's really that simple. The ancestors of people who are native to Central and northern Europe (like all humans) came from people who were dark skinned and had to adapt over the generations to be able to take advantage of the low UV environment they now inhabited. The consequential lightning of the skin allowed for more sun and vitamin D accessibility and aided in preventing frostbite, which affects darker skin at a more rapid rate than those with lighter skin tones.

The adaptation for lighter skin evolved 3 separate times independently in Europe in an amazing example of convergent evolution. Neanderthals were the first to develop light skin independently, roughly hundreds of thousands of years ago, to adapt to their ice age climate. Humans who entered Europe tens of thousands of years ago split into numerous populations, in which western and northern European groups independently achieved lighter skin with the same genetic mutation at different periods. Those who left Africa and went into southern Asia, Australia, and Oceania retained dark skin as it was advantageous to the high UV exposure to sunlight, and even reflected on what they ate. A diet high in animal organs and fatty acids results in a ton of Vitamin D intake, which was discovered to be the reason as to why inuit people retained genetic imprints for dark skin while compared to other northern peoples such as the Sami in Europe or the Nanai of Siberia who live in similar conditions, but have a more varied diet.

Ultimately, our differences are fascinating, and the adaptations our ancestors made to survive in their environments live on in us today. It just goes to show that our differences might only be skin deep.