Evolution of Skin Color Practice Exam Questions Correctly Answered.

Evolution of Skin Color Practice Exam Questions Correctly Answered. KEY CONCEPTS of evolution of skin color - CORRECT ANSWER Within a population, heritable traits that provide a survival and reproductive advantage in a particular environment are more likely than other traits to be passed on to the next generation and thus tend to become more common over time. These traits are known as adaptations. Human populations living in different parts of the world have different sets of evolutionary adaptations. These include wide-ranging variations in the way people look, especially with respect to skin color. Evidence from different disciplines can inform what makes a human trait beneficial or harmful in a particular environment. Evolution involves tradeoffs; a change in a gene that results in an adaptation to one aspect of the environment may be linked to a disadvantage with respect to another aspect of that same environment. Describe the relationship between the UV Index (the colored bar in Figure 1) and latitude (y-axis) - CORRECT ANSWER UV radiation is most intense near the equator and least intense toward the poles. Students may also say it is most intense at lower latitudes and increasingly intense as latitude increases. How do you explain the relationship between the UV Index and latitude (In other words, why does UV intensity change with latitude - CORRECT ANSWER ) The answer has to do with the angle of Earth relative to the sun. Latitudes at the equator receive direct sunlight year-round. Latitudes toward the poles receive sunlight at an oblique angle, which means that the same amount of radiation is spread out over a larger area than at the equator. Find your approximate location on the map. What is the primary UV Index value of your state on thi particular day in September? Answers will vary depending on location. Most states in the U.S. have a UV index between 4 and 6. Look at the regions that receive the most-intense UV (light pink). Site a specific piece of evidence from the map that a factor other than latitude was contributing to UV intensity on this day - CORRECT ANSWER The Andes and Himalayas have higher UV Index values than you'd expect, which is evidence that UV intensity increases with higher altitude. Students may also say that there might be decreased cloud cover or greater humidity. All these answers would be acceptable. In the film, Dr. Jablonski explains that melanin, located in the top layer of human skin, absorbs UV radiation, protecting cells from the damaging effects of UV. Genetics determines the type of melanin (i.e., brown/black eumelanin or red/brown pheomelanin) and the amount of melanin present in an individual's cells. Based on this information, write a hypothesis for where in the world you would expect to find human populations with darker or lighter skin pigmentation (i.e., different amounts of melanin) -