Skin: Ultraviolet and Darkly Pigmented People
1.What are the causes of skin cancer?
Most skin cancer are caused by sun exposure. Exposure to some chemicals and in rare cases the abnormal genes that cause skin cancer can be inherited by children from their parents
2. Why are Caucasians more at risk of skin cancer than other populations?
Caucasians are more likely to sun damage and skin cancer than people with more pigment in their skin.
3.At what age does skin cancer typically occur? Is the incidence of skin cancer greater in youth or old age?
People over 50 years of age. However people who are exposed to large quantities of ultraviolet radiation can develop skin cancer as early as 20 to 30 years of age. The average age of skin cancer diagnosis occurs at 53 years old.
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)?
8.Interpret this graph and the trend it describes.
a).Is skin reflectance randomly distributed throughout the globe? If not, how would you describe the pattern?
9.Hypothesize why different skin colors have evolved. Based on what you know, what factor is most likely to exert a selective pressure on skin color?
10.Review your answer to Question 3. Keeping your answer in mind, how strong a selective pressure do you expect skin cancer (UV-induced mutations) to exert on reproductive success?
11.Based on this information, does your hypothesis about the evolution of skin color (Question 9) seem likely? Why or why not? How does skin color meet, or fail to meet, the three requirements of natural selection outlined above?
12. Based on Branda and Eaton’s
Most skin cancer are caused by sun exposure. Exposure to some chemicals and in rare cases the abnormal genes that cause skin cancer can be inherited by children from their parents
2. Why are Caucasians more at risk of skin cancer than other populations?
Caucasians are more likely to sun damage and skin cancer than people with more pigment in their skin.
3.At what age does skin cancer typically occur? Is the incidence of skin cancer greater in youth or old age?
People over 50 years of age. However people who are exposed to large quantities of ultraviolet radiation can develop skin cancer as early as 20 to 30 years of age. The average age of skin cancer diagnosis occurs at 53 years old.
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)?
8.Interpret this graph and the trend it describes.
a).Is skin reflectance randomly distributed throughout the globe? If not, how would you describe the pattern?
9.Hypothesize why different skin colors have evolved. Based on what you know, what factor is most likely to exert a selective pressure on skin color?
10.Review your answer to Question 3. Keeping your answer in mind, how strong a selective pressure do you expect skin cancer (UV-induced mutations) to exert on reproductive success?
11.Based on this information, does your hypothesis about the evolution of skin color (Question 9) seem likely? Why or why not? How does skin color meet, or fail to meet, the three requirements of natural selection outlined above?
12. Based on Branda and Eaton’s