17a test by n5Qh71MG

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    17 Evolution of Populations                                   Chapter Test A

Multiple Choice
Write the letter that best answers the question or completes the statement on the line provided.
_____ 1. Natural selection acts directly on
           a. alleles.                        c. phenotypes.
           b. genes.                          d. mutations.
_____ 2. In organisms that reproduce sexually, most variation that can be inherited is due to
         a. mutations during gamete formation
         b. polygenic traits
         c. gene recombination during sexual reproduction
         d. the effects of radiation.
_____ 3. The number of phenotypes produced for a given trait depends upon
         a. the number of genes that control the trait.
         b. which form of the trait is dominant.
         c. the allele frequencies of the various alleles.
         d. the relationship of allele frequencies to Mendelian ratios.
_____ 4. One end of Figure 17–1 shows an increase in
         average beak size for a population of birds.
         When individuals at only one end of a bell
         curve of phenotype frequencies have high
         fitness, the result is
         a. directional selection.
         b. stabilizing selection.
         c. disruptive selection.
         d. genetic drift.                                                Figure 17–1
_____ 5. Figure 17–2 shows highest fitness toward the
         center of the curve. When individuals with an
         average form of a trait have the highest
         fitness, the result is
         a. not predictable.
         b. disruptive selection.
         c. directional selection
         d. stabilizing selection.


                                                                          Figure 17–2




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_____ 6. If a mutation introduces a new skin color in a lizard population, which factor might
         determine whether the frequency of the new allele will increase?
          a. how many other alleles are present
         b. whether the mutation makes some lizards more fit for their environment than other lizards
         c. how many phenotypes the population has
         d. whether the mutation was caused by nature or by human intervention
_____ 7. Which of the following events do biologists consider a random change?
         a. directional selection         c. disruptive selection
         b. speciation                    d. genetic drift
_____ 8. The situation in which allele frequencies in the gene pool of a population remain constant is
         called
         a. evolution.                      c. genetic equilibrium.
         b. genetic drift.                  d. natural selection.
_____ 9. The allele frequencies of a population are more likely to change if
         a. the population size is increased.
         b. no immigration or emigration occurs.
         c. mating is not random.
         d. the mutation rate decreases.
_____ 10. A factor that is necessary for the formation of a new species is
          a. reproduction at different times. c. different mating behaviors.
          b. geographic barriers.             d. reproductive isolation.
_____ 11. What situation might develop in a population having some plants whose flowers open at
         midday and other plants whose flowers open late in the day?
         a. behavioral isolation           c. temporal isolation
         b. geographic isolation           d. genetic drift
_____ 12. What did the Grants learn about mate choice from the Galápagos finches?
          a. Phenotype plays no role in mate choice.
          b. Finches prefer mates with beaks similar in size to their own.
          c. Finches prefer mates with smaller beaks than their own.
          d. Finches prefer mates with larger beaks than their own.
_____ 13. Species Y and Z have very different proteins and genes. What is most likely true about
          these two species? Species Y
         a. is older than Species Z.
         b. is younger than Species Z.
         c. evolved for a long time separately from Species Z.
         d. shares a relatively recent common ancestor with Species Z.



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_____ 14. Which of the following can produce a duplicate gene?
         a. chromosome replication during mitosis
         b. crossing-over during meiosis
         c. neutral mutation during transcription
         d. genetic drift during reproduction
_____ 15. What do Hox genes control?
          a. gene duplication                  c. patterns of embryological development
          b. mutations                         d. molecular clocks

Completion
Complete each statement on the line provided.
16. A(n)                          is all of the genes that are present in a particular population.
17. The passing of genes from one organism to another organism that is not its offspring is called
                              .
18. In the Galápagos finches that the Grants studied, a pattern of natural selection called
                             selection favored individuals with larger, heavier beaks during a drought.
19. In a particular environment, populations that are very different from each other are less likely
    to                         with each other for resources.
20. A(n)                      uses mutation rates in DNA to estimate the time that two species have
    been evolving independently.

Short Answer
In complete sentences, write the answers to the questions on the lines provided.
21. Are the members of a population necessarily the same species? Explain.



22. Is an allele for a trait that has no effect on a species’ fitness affected by natural selection? Explain.



23. How does the size of a population relate to genetic drift?




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24. How can gene duplication affect evolution?



25. What might happen when a Hox gene turns other genes on or off ?




Using Science Skills
Use the diagram below to answer the following questions on the lines provided.




                                             Figure 17–3

26. Interpret Graphs Describe the information about frog species that is shown in Figure 17–3.



27. Interpret Graphs According to Figure 17–3, there is a brief period during which frog mating
     nearly stops. When does this occur?



28. Infer Based on Figure 17–3, what mechanism appears to keep bullfrogs reproductively isolated?
     Would that mechanism necessarily be the only isolating mechanism? Explain.



29. Infer Peeper frogs and leopard frogs do not interbreed even when they share a habitat. Use the
     information in Figure 17–3 to determine what mechanism probably keeps the two species
     reproductively isolated.




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30. Predict Frog mating does not occur in cold weather. Assume that the mating times shown in
    Figure 17–3 are for frogs in the northern part of the United States. How might these curves change
    for frogs in the southern part of the United States? Explain.




Essay
Write the answer to each question in the space provided.
31. For a population, are the frequencies of phenotypes for a single-gene trait best expressed by a bar
    graph or a curve? Are the frequencies of phenotypes for a polygenic trait best expressed by a bar
    graph or a curve? Explain.




32. Describe the founder effect, and describe the conditions in which it arises.




33. The Hardy-Weinberg principle describes the conditions that can change the frequency of alleles in
    a population. Explain how that change occurs.




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34. If each of the Galápagos Islands had contained an identical assortment and abundance of
     vegetation, would the effect of natural selection have been as pronounced as it was? Explain.




35. Describe one way that new genes can evolve.




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