This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: B. Individuals do not evolve, but populations do. C. The organisms that exist today do so because their ancestors had traits that allowed them and their offspring to thrive. D. At the molecular level, evolution can take place by the replacement of one nucleotide by another. E. Evolution is said to have occurred within a population when measurable genetic changes are detected. 9. Explain why changes in the homeotic genes could explain major morphological differences between species. AP BIOLOGY 2 10. During the past 50 years, more than 200 species of insects that attack crop plants have become highly resistant to DDT and other pesticides. A. Explain the rapid and widespread evolution of resistance. B. Propose ways of using pesticides that would slow down the rate of evolution of resistance. C. Now that use of DDT has been banned in the United States, what do you expect to happen to levels of resistance to DDT among insect populations? Justify your answer. 11. Natural selection works upon the natural variation found within species. What processes lead to this variation? 12. Create a table with three columns and six rows. Title the columns “Event,” “Effect on Populations,” and “Example.” In the rows of the “Event” column, write “Mutation,” “Gene Flow,” “Sexual Selection,” “Genetic Drift,” “Natural Selection,” and “None (Hardy-Weinberg Conditions).” Fill in the rest of the table. 13. Explain why genetic drift has a much larger impact in small populations than in large populations. Compare and contrast the bottleneck effect with the founder effect . 14. Draw diagrams of each of the three types of natural selection and provide an example of how species would evolve under each type of selective pressure. How do these types of selection relate to polymorphism? 15. Why does sexual selection often lead to sexual dimorphism? Why are males usually the sex that exhibits the exaggerated characteristics? 16. Describe why coevolution occurs. In addition, give an example of coevolution for each of the following situations: predator-prey, competition & mutualism. 17. Populations of most of the thousands of species that have been introduced to areas where they were previously not found, including those that have become pests, began with a few individuals. They should therefore have begun with much less genetic variation than the parent populations have. If genetic variation is advantageous, why have so many of these species been successful in their new environments?...
View Full Document
- Fall '11