Why Ancient Humans Went From Dark to Light Skin?

For more than a million years, your ancestors were dark-skinned. Light skin became common across most of Europe only in the last several thousand years. The color of your skin is a record of how much sunlight your ancestors lived under, what they ate and where they moved. What you'll find in this video: Melanin works like a sunscreen your body makes for free. In a 1979 study, the outer layer of dark skin let through about 5.7 percent of the UVB that hit it, and light skin about 29 percent. Sunlight breaks down folate, a B vitamin a baby needs in the first weeks of pregnancy. In 1978, blood plasma under strong artificial light lost 30 to 50 percent of its folate in an hour, and scientists are still testing how much that matters inside the body. Your skin makes vitamin D from UVB light. In Boston the winter sun is too weak for that four months a year, and in Edmonton about six. Cheddar Man lived in Britain about 10,000 years ago, and his DNA suggests he most likely had dark skin and blue or blue-green eyes. A big part of the change in Europe arrived with farmers from Anatolia, who already carried a light-skin version of a gene called SLC24A5. Europeans and East Asians got lighter skin through largely different genes, and blue eyes turned out to be at least 17,000 years old, far older than light skin across most of Europe. If you enjoyed this, a like helps the video reach more people. Subscribe for the next one, and tell us in the comments which of your own traits you think has the strangest backstory. 0:00 Look at the back of your hand 1:50 A sunscreen you were born with 4:12 The vitamin sunlight breaks down 6:09 Walking away from the equator 7:39 The vitamin only sunlight can make 9:58 Dark skin and blue eyes 11:28 The farmers from Anatolia 13:38 Two roads to lighter skin 15:10 Older than farming 16:43 A dial set by the sun Everything in this video comes from open sources. Treat it as a starting point rather than the final word. Figures get revised and studies get challenged, and we make mistakes like anyone else. Always check the facts for yourself before you rely on them or pass them on. #skincolor #evolution #why