Survival Of The Sickest Analysis
Dr. Sharon Moalem's New York Times Bestseller Survival of the Sickest discusses how diseases and health conditions of the modern era have a direct connection with the results of evolutionary pressures of early human life. As the modern homo sapiens first evolved from the continent of Africa over 200,000 years ago, the species would be forced to slowly develop new characteristics and adapt to changes over thousands of years. As humans began to move out of the African continent and settle in various parts of Earth, our early ancestors' tolerance for different environments would inevitably be challenged. Beneficial genetic mutations would be present in an individual and as he reproduced, those with the mutation slowly but surely outnumbered those
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Moalem suggests that all humans had pale skin with dark hair all over to protect ourselves from too much sunlight. However, as the human evolved and lost a significant amount body hair, the skin, the largest organ of the body, would become exposed to the strong ultraviolet rays of the sun. Ultraviolet B, a specific type of ultraviolet light, is beneficial as it effectively converts our cholesterol into Vitamin D, which the body cannot simply live without. However, too much sunlight exposure and harmful effects quickly outnumber the beneficial ones, ranging from sunburn to skin cancer and the decrease of our body's folic acid. Thus, humans, especially those near the equator, developed a darker skin tone with the pigment melanin. While the color of the dark skin absorbs more heat and light, the melanin in the skin prevents too much of the harmful rays from penetrating the skin, protecting folic acid. However, "[dark skin] didn't evolve with a switch -- you can't turn it off when you need to whip up a batch of vitamin D." That is where the genetic mutation apolipoprotein E, or ApoE4 for short, came in. "[ApoE4] ensures that the amount of cholesterol flowing through your blood is cranked up. With more cholesterol available for conversion, dark-skinned people can maximize the use of whatever sunlight penetrates their skin." The fair-skinned Europeans of the time
Moalem suggests that all humans had pale skin with dark hair all over to protect ourselves from too much sunlight. However, as the human evolved and lost a significant amount body hair, the skin, the largest organ of the body, would become exposed to the strong ultraviolet rays of the sun. Ultraviolet B, a specific type of ultraviolet light, is beneficial as it effectively converts our cholesterol into Vitamin D, which the body cannot simply live without. However, too much sunlight exposure and harmful effects quickly outnumber the beneficial ones, ranging from sunburn to skin cancer and the decrease of our body's folic acid. Thus, humans, especially those near the equator, developed a darker skin tone with the pigment melanin. While the color of the dark skin absorbs more heat and light, the melanin in the skin prevents too much of the harmful rays from penetrating the skin, protecting folic acid. However, "[dark skin] didn't evolve with a switch -- you can't turn it off when you need to whip up a batch of vitamin D." That is where the genetic mutation apolipoprotein E, or ApoE4 for short, came in. "[ApoE4] ensures that the amount of cholesterol flowing through your blood is cranked up. With more cholesterol available for conversion, dark-skinned people can maximize the use of whatever sunlight penetrates their skin." The fair-skinned Europeans of the time