Sickle Cell Mutation Essay

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Chapter 8: Questions 2 & 3 2. What makes the sickle-cell mutation a balanced polymorphism? -The sickle cell mutation is a balanced polymorphism because the heterozygote has an advantage over either homozygote. The data shows that, in areas of high malaria content, about “26 percent more AS heterozygote children than AA homozygote children reached adulthood”, which reveals one of the largest selective advantages ever measured for a single trait. 3. Why was the demonstration of human resistance to malaria important to evolutionary biology? -Tony Allison’s demonstration of human resistance to malaria is important to evolutionary biology because it proves that the agent of natural selection is still active. Also, his discovery is important…show more content…
An organism stops expressing the traits of a fossil gene because of the lack of use. For example, ice fish, when they were examined, had a remnant of the alpha-hemoglobin was detected and there was no beta-hemoglobin at all. “The remaining chunk of the alpha-hemoglobin gene is a molecular fossil, or pseudo gene, a vestige of red-blooded way of life in ice fish ancestors that was abandoned.” 3. How do ice fish obtain their oxygen? What might happen to ice fish if the waters around the Antarctic became warmer? -They have a few methods of coping with the lack of hemoglobin. One mechanism being that they obtain oxygen from large capillaries throughout the fish, and its larger gills. It also has a much larger heart to help pump the blood throughout the body more efficiently. The lack of red blood cells keeps the fish from freezing and the viscosity of the blood is also lower. This fish is designed to live in cold climates, if for any reason it were to get warmer the fish would not be able to live. It has no way for it to deal with the warmer environment and it has evolved specifically to obtain oxygen and retain heat in a cold environment, not a warm

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