From the article: “Out of Africa”
There are two main reasons why the human race has so many different skin colors. The first reason it that our skin is our shield from the sun so it has to act as sunscreen from UV rays. The second reason is that our bodies have to produce vitamin D in order to survive, so depending on your location, your skin will be light or dark.
UV radiation from the sun is very damaging, so to protect us, our bodies produce melanin. It all started seven million years ago when we evolution took place in chimpanzees and the human race began. With that evolution the first humans began to lose hair and then their light skin color changed. This is due to prevent over heating of the brain, but once the hair was gone our skin needed protection so melanin became our sunscreen. It takes up LTV rays, causing them to lose energy and it defuses destructive chemicals that form in the skin after UV radiation damage. This would help people on the tropical areas prevent skin cancer. It also helps protect folate, which prevents neural tube faults and is essential for the production of DNA; folate can be broken down easily by UV radiation.
Yet as early humans began to migrate across the continents they were exposed to different climates. In Africa, the people adapted to the harsh UV radiation by having darker skin, but when they moved away from those tropical areas they didn’t experience as much UV radiation. So they had a lesser need for melanin. But there is another explanation for not needing as much melanin. UVB rays do help by commencing the formation of vitamin D, so when people with dark pigmentation entered a less harsh UV radiation area they need a way to get that U
V radiation into their skin, so the skin lost pigmentation to enable that. Vitamin D is very important because it allows calcium absorption in the intestines which cause for normal development of the skeleton and the preservation a healthy immune system. So as you can see places like the tropics are high in UVB so the people there are darker and produce vitamin D all year long. Whereas people in subtropics and temperate areas have a less amount of UVB during the year, so their skin has to be able to absorb as much of it as possible causing them to be lighter skinned.
A few other factors are also involved in your skin coloration. You’re sex is one; women have a higher need for calcium, due to of reproduction, so they are lighter skinned then men. Your cultural traditions, such as if your ancestors were more agricultural and pastoral then they would of wore heavy clothing which would cause a lesser need of melanin. But today our culture involves a great amount of traveling and moving to different areas. This can be hard for our bodies to keep up with UVB, causing some deficiency on UV radiation and vitamin D.
In the end there are so many different skin colors because of the way people migrated to different areas of UVB and because our bodies require vitamin D as well as protection from UV radiation.
There are two main reasons why the human race has so many different skin colors. The first reason it that our skin is our shield from the sun so it has to act as sunscreen from UV rays. The second reason is that our bodies have to produce vitamin D in order to survive, so depending on your location, your skin will be light or dark.
UV radiation from the sun is very damaging, so to protect us, our bodies produce melanin. It all started seven million years ago when we evolution took place in chimpanzees and the human race began. With that evolution the first humans began to lose hair and then their light skin color changed. This is due to prevent over heating of the brain, but once the hair was gone our skin needed protection so melanin became our sunscreen. It takes up LTV rays, causing them to lose energy and it defuses destructive chemicals that form in the skin after UV radiation damage. This would help people on the tropical areas prevent skin cancer. It also helps protect folate, which prevents neural tube faults and is essential for the production of DNA; folate can be broken down easily by UV radiation.
Yet as early humans began to migrate across the continents they were exposed to different climates. In Africa, the people adapted to the harsh UV radiation by having darker skin, but when they moved away from those tropical areas they didn’t experience as much UV radiation. So they had a lesser need for melanin. But there is another explanation for not needing as much melanin. UVB rays do help by commencing the formation of vitamin D, so when people with dark pigmentation entered a less harsh UV radiation area they need a way to get that U
V radiation into their skin, so the skin lost pigmentation to enable that. Vitamin D is very important because it allows calcium absorption in the intestines which cause for normal development of the skeleton and the preservation a healthy immune system. So as you can see places like the tropics are high in UVB so the people there are darker and produce vitamin D all year long. Whereas people in subtropics and temperate areas have a less amount of UVB during the year, so their skin has to be able to absorb as much of it as possible causing them to be lighter skinned.A few other factors are also involved in your skin coloration. You’re sex is one; women have a higher need for calcium, due to of reproduction, so they are lighter skinned then men. Your cultural traditions, such as if your ancestors were more agricultural and pastoral then they would of wore heavy clothing which would cause a lesser need of melanin. But today our culture involves a great amount of traveling and moving to different areas. This can be hard for our bodies to keep up with UVB, causing some deficiency on UV radiation and vitamin D.
In the end there are so many different skin colors because of the way people migrated to different areas of UVB and because our bodies require vitamin D as well as protection from UV radiation.
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