# Uv Essay

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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 ne. 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. is woman now has to wait for the lab results to see if it was cancerous. If it is, maybe we caught
Distribution of UV Light across the Globe e following image (Figure 1) represents a map of the world on which the UV-light Index has been superimposed. e latitudes are shown on the left (latitude helps de ne a location on Earth, speci cally 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? e least? 6. Based on these data, where might you expect to nd the most lightly pigmented and most darkly pigmented people on the planet? Be as speci c 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)?

e Evolution of Human Skin Color” by Annie Prud’homme-Généreux

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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. ncep.noaa.gov/products/stratosphere/uv_index/gif_ les/uvi_world_f1.gif. is U.S. Government material is not subject to copyright protection within the United States.

e Evolution of Human Skin Color” by Annie Prud’homme-Généreux

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NATIONAL