Based on your answer to Question #10, does your hypothesis about the evolution of skin color (Question 9) seem likely? ... Why does protection from skin cancer not explain the strong selective pressure for dark skin in high UV ares. Human skin color ranges from the darkest brown to the lightest hues. ... Based on what you know, what factor is most likely to exert a selective pressure on skin color? In her latest book, anthropologist Nina Jablonski describes the connections between skin color and Vitamin D. Credit: University of California Press (Get a 29% discount on this book from the NASW Bookstore on Amazon.com).. With receptors located in the cells of many major organs and in the immune system, Vitamin D helps in calcium absorption and prevents aberrant cell division. What might explain the skin color of these exceptional populations? 9. Human populations in low-UV environments tend to have more lightly pigmented skin. Children born to mothers with light skin, living close to the equator. Differences in skin color among individuals is caused by variation in pigmentation, which is the result of genetics (inherited from one's biological parents), the exposure to the sun, or both.Differences across populations evolved through natural selection, because of differences in environment, and regulate the … Most humans are not extremely light skinned or extremely dark skinned. And perhaps people didn’t make enough vitamin D. After some time, someone had a random DNA mutation that made his or her skin tone lighter. About 40,000 years ago, when some people moved from Africa to Northern Europe, their new home had a lot less sun. Propose a few hypotheses. What is the selection for the evolution of lighter skin Protection of folate from destruction can explain the selective pressure for the evolution of darker skin. The lower the reflectance value, therefore, the darker the skin. Now let’s think about natural selection and human skin color. One explanation is that the selective pressure for dark skin decreases as UV intensity decreases. answer choices . Hypothesize why different skin colors have evolved. data point falls somewhere outside of the line shown in Figure 2). Restate your findings in terms of skin color and UV light (instead of skin reflectance and latitude). Describe in terms of the three requirements of natural selection. If a person lives in an environment with low radiation what kind of skin color would be the best adapted. Stabilizing selection is the type of natural selection that human skin color follows. 11 . This creates a very large peak right in the middle of the bell curve. ... natural selection favors lighter skin which allowed UV rays to penetrate the skin and produce more vitamin D. Indigenous populations in low-UV environments tend to have lighter skin tones. Figure 2. What factor you think is most likely to exert a selective pressure on skin color? Because the median age is 63. The majority of the species fall somewhere in the middle of those two extremes. 10. Why or why not? Scientists can shine visible light on a portion of skin (typically the inside of the arm) and then measure how much light is reflected back. One way to measure skin color is to look at skin reflectance. However, it does not explain why there is variation in human skin color. What age does skin cancer typically occur? Lighter skin colours tend to burn much easier than darker ones; because of this a light skinned person living in an area with high UV light exposure would suffer frequent and severe burns causing damaged and tender skin and even skin cancer. Based on what you know, what factor is most likely to exert a selective pressure on skin colour? One hypothesis is that, in low-UV environments, the selective pressure for dark skin is low. Measures of skin reflectance, a way to quantify skin color by measuring the amount of light it reflects, in people around the world support this idea. Dark skin reflects less visible light than does light skin. 6. At the same time there is selection for lighter skin to absorb more UV radiation, which is needed for vitamin D production. Instead, there is selective pressure for lighter skin, which absorbs more UV radiation, since UV is needed for vitamin D production. Based on what you know, what factor is most likely to exert a selective pressure on skin color?
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