Chapter 23 Evolution of Populations
Objectives
| Population Genetics | |||
| 1. | Explain the statement “It is the population, not the individual, that evolves.” | ||
| 2. | Explain how Mendel’s particulate hypothesis of inheritance provided much-needed support for Darwin’s theory of evolution by natural selection. | ||
| 3. | Distinguish between discrete and quantitative traits. Explain how Mendel’s laws of inheritance apply to quantitative traits. | ||
| 4. | Explain what is meant by “the modern synthesis.” | ||
| 5. | Define the terms population, species, and gene pool. | ||
| 6. | Explain why meiosis and random fertilization alone will not alter the frequency of alleles or genotypes in a population. | ||
| 7. | List the five conditions that must be met for a population to remain in Hardy-Weinberg equilibrium. | ||
| 8. | Write the Hardy-Weinberg equation. Use the equation to calculate allele frequencies when the frequency of homozygous recessive individuals in a population is 25%. | ||
| Mutation and Sexual Recombination | |||
| 9. | Explain why the majority of point mutations are harmless. | ||
| 10. | Explain why mutation has little quantitative effect on allele frequencies in a large population. | ||
| 11. | Describe the significance of transposons in the generation of genetic variability. | ||
| 12. | Explain how sexual recombination generates genetic variability. | ||
| Natural Selection, Genetic Drift, and Gene Flow | |||
| 13. | Explain the following statement: “Only natural selection leads to the adaptation of organisms to their environment.” | ||
| 14. | Explain the role of population size in genetic drift. | ||
| 15. | Distinguish between the bottleneck effect and the founder effect. | ||
| 16. | Describe how gene flow can act to reduce genetic differences between adjacent populations. | ||
| Genetic Variation, the Substrate for Natural Selection | |||
| 17. | Explain how quantitative and discrete characters contribute to variation within a population. | ||
| 18. | Distinguish between average heterozygosity and nucleotide variability. Explain why average heterozygosity tends to be greater than nucleotide variability. | ||
| 19. | Define a cline. | ||
| 20. |
Define relative fitness. a. Explain why relative fitness is zero for a healthy, long-lived, sterile organism. b. Explain why relative fitness could be high for a short-lived organism. |
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| 21. | Distinguish among directional, disruptive, and stabilizing selection. Give an example of each mode of selection. | ||
| 22. | Explain how diploidy can protect a rare recessive allele from elimination by natural selection. | ||
| 23. | Describe how heterozygote advantage and frequency-dependent selection promote balanced polymorphism. | ||
| 24. | Define neutral variations. Explain why natural selection does not act on these alleles. | ||
| 25. | Distinguish between intrasexual selection and intersexual selection. | ||
| 26. | Explain how female preferences for showy male traits may benefit the female. | ||
| 27. | Describe the disadvantages of sexual reproduction. | ||
| 28. | Explain how the genetic variation promoted by sex may be advantageous to individuals on a generational time scale. | ||
| 29. | List four reasons why natural selection cannot produce perfect organisms. | ||
