The Evolution of Human Skin Color

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NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE The Evolution of Human Skin Color by Annie Prud’homme-Généreux Life Sciences Quest University, Canada Part I – Skin Cancer “Stop it!” called Tatiana, playfully. Her boyfriend, Zach, was inspecting her skin very carefully. “Look,” he answered her, his voice taking on a more serious tone. “Today a woman walked into the clinic for her annual physical. Everything about her seemed fine. She leads a balanced lifestyle, she eats well, she exercises: she’s healthy! But as she was about to leave, I noticed a mole on her arm. It had many of the warning signs of skin cancer. So, I removed the mole. This woman now has to wait for the lab results to see if it was cancerous. If it is, maybe we…show more content…
Distribution of UV Light across the Globe The following image (Figure 1) represents a map of the world on which the UV-light Index has been superimposed. The latitudes are shown on the left (latitude helps define a location on Earth, specifically how far north or south of the equator a site is). Questions 4. Does the amount of UV light reaching the Earth vary in a predictable manner? If so, describe the pattern you observe. 5. What latitude receives the greatest amount of UV light? The least? 6. Based on these data, where might you expect to find the most lightly pigmented and most darkly pigmented people on the planet? Be as specific as you can. 7. Provide a rationale to your answer above (i.e., why did you think that more darkly pigmented people would be found in those areas)? “The Evolution of Human Skin Color” by Annie Prud’homme-Généreux Page 2 NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE Figure 1. Global UV Index Forecast. Source: Figure obtained from the National Oceanic and Atmospheric Administration. Graph retrieved 18 October 2009 from http://www.cpc. This U.S. Government material is not subject to copyright protection within the United States. “The Evolution of Human Skin Color” by Annie
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