1、生态学英文题库CHAPTER 7 Evolution and AdaptationThe process of evolution depends on genetic variation.MULTIPLE CHOICE1. Topic: The process of evolution depends on genetic variation.Level: easyDifferent forms of a particular gene are known asa. chromosomes.b. alleles.c. polygenic.d. pleiotropic.Answer: b2.
2、Topic: The process of evolution depends on genetic variation.Level: easyA trait that is determined by multiple genes is referred to asa. polygenic.b. pleiotropic.c. homozygous.d. heterozygous.Answer: a3. Topic: The process of evolution depends on genetic variation.Level: mediumChickens with the domi
3、nant allele at the frizzle gene produce curly feathers, have very high body temperature, and lay few eggs. This is an example ofa. polygenic traits.b. pleiotropy.c. epistasis.d. random assortment.Answer: b4. Topic: The process of evolution depends on genetic variation.Level: mediumTwo of the genes t
4、hat affect coat color in horses are the extension gene and the cream dilution gene. The dominant E allele at the extension gene generates black coats, while the recessive e allele produces red coats. The coat color caused by the extension gene is not altered if the horse is a homozygote for the C al
5、lele at the cream dilution gene. However, if the horse is a homozygote for the CCr allele at the cream dilution gene, it will have a white coat regardless of the extension genotype. This interaction between the extension and the cream dilution gene is an example ofa. pleiotropy.b. epistasis.c. codom
6、inance.d. random assortment.Answer: b5. Topic: The process of evolution depends on genetic variation.Level: difficultWhich of the following types of allele would we expect to have the lowest frequency in a population?a. beneficial recessive alleleb. beneficial dominant allelec. harmful recessive all
7、eled. harmful dominant alleleAnswer: d6. Topic: The process of evolution depends on genetic variation.Level: mediumConsider a gene that affects fur color in mice. This gene has two alleles, A and a. If AA mice have white fur, Aa mice have gray fur, and aa mice have black fur, how would we describe t
8、he effect of these alleles?a. A is dominant and a is recessive.b. A is recessive and a is dominant.c. A and a are codominant.d. A and a are epistatic.Answer: c7. Topic: The process of evolution depends on genetic variation.Level: mediumConsider a gene that affects number of seeds in a plant. This ge
9、ne has two alleles, G and g. If GG plants produce 50 seeds, Gg plants produce 50 seeds, and gg plants produce 25 seeds, how would we describe the effect of these alleles?a. G is dominant and g is recessive.b. G is recessive and g is dominant.c. G and g are codominant.d. G and g are polygenic.Answer:
10、 a8. Topic: The process of evolution depends on genetic variation.Level: easyWhat term refers to the alleles of all of the genes of every individual in a population?a. polygenicb. heterozygousc. gene poold. random assortmentAnswer: c9. Topic: The process of evolution depends on genetic variation.Lev
11、el: easyWhat process creates new alleles in a population?a. random assortmentb. mutationc. recombinationd. epistasisAnswer: b10. Topic: The process of evolution depends on genetic variation.Level: difficultFor mutations that enter a population of a diploid organism, which type of mutation is most li
12、kely to be affected by natural selection when it first appears?a. synonymous mutationb. nonsynonymous recessive mutationc. nonsynonymous dominant mutationd. All are equally likely to be affected by natural selection.Answer: c11. Topic: The process of evolution depends on genetic variation.Level: eas
13、yThe shuffling of genes that occurs when DNA is copied during meiosis is known asa. recombination.b. mutation.c. random assortment.d. epistasis.Answer: a12. Topic: The process of evolution depends on genetic variation.Level: easyWhat term describes making new combinations of alleles using existing g
14、enetic variation across many chromosomes?a. pleiotropyb. epistasisc. random assortmentd. mutationAnswer: cSHORT ANSWER13. Topic: The process of evolution depends on genetic variation.Level: mediumClonal animals do not reshuffle their genes through genetic recombination, whereas sexually reproducing
15、animals do. Explain how this difference could affect how pathogens interact with clonal animals and how they interact with sexually reproducing animals.Answer: Since recombination creates new genotypes every generation, pathogens cannot become fully adapted to the genotypes of sexually reproducing a
16、nimals. Because recombination does not occur in clonal animals, they gain new genetic variation only through mutation, which is a very rare process. Thus pathogens can more easily adapt to the genetic variation in clonal animals.14. Topic: The process of evolution depends on genetic variation.Level:
17、 difficultDescribe the difference between synonymous and nonsynonymous mutation. Which type is more likely to be affected by natural selection, and why?Answer: A synonymous mutation does not affect an organisms phenotype, whereas a nonsynonymous mutation does affect phenotype. Natural selection acts
18、 on variation among phenotypes, and so natural selection will act only on nonsynonymous mutations, because they are the only mutations that affect an organisms phenotype. 15. Topic: The process of evolution depends on genetic variation.Level: difficultMany genetic diseases have severe or lethal effe
19、cts in the homozygous form, yet alleles for these diseases are not entirely removed by natural selection. Explain how dominance relationships among alleles allow deleterious mutations to remain in a population.Answer: When genetic diseases are caused by recessive alleles, they do harm to the carrier
20、 only in the homozygous form. The heterozygotes do not express the deleterious phenotype, and thus heterozygotes do not have reduced fitness. Deleterious genetic diseases thus can remain in the population because they are not selected against in the heterozygous form.Evolution can occur through rand
21、om processes or through selection.MULTIPLE CHOICE16. Topic: Evolution can occur through random processes or through selection.Level: easyA process that occurs when genetic variation is lost because of random variation in mating, mortality, fecundity, and inheritance is known asa. mutation.b. genetic
22、 drift.c. stabilizing selection.d. disruptive selection.Answer: b17. Topic: Evolution can occur through random processes or through selection.Level: mediumThe rate at which allele frequencies change because of genetic drift isa. highest in large populations.b. the same regardless of population size.
23、c. highest in intermediate-sized populations.d. highest in small populations.Answer: d18. Topic: Evolution can occur through random processes or through selection.Level: mediumConsider three populations of a plant species, each isolated from other populations of the same species. Population X has co
24、ntained approximately 100 individuals in each generation for the past 200 generations. Population Y has contained approximately 10,000 individuals in each generation for the past 200 generations. Population Z has contained approximately 1 million individuals in each generation for the past 200 gener
25、ations. If genetic drift is the only evolutionary process acting on these populations, how can we expect the amount of genetic variation to differ among these populations?a. X will have the highest variation, Y will have intermediate variation, and Z will have the lowest variation.b. X will have the
26、 lowest variation, Y will have intermediate variation, and Z will have the highest variation.c. X and Z will have high variation, while Z will have low variation.d. All three populations will have the same amount of genetic variation.Answer: b19. Topic: Evolution can occur through random processes o
27、r through selection.Level: medium Which is (are) correct about founder effect?I. Founder effect occurs when individuals are transplanted to a new location.II. Founder effect produces new alleles.III. Founder effect reduces genetic variation.a. I onlyb. II onlyc. III onlyd. I and II e. I and III Answ
28、er: e20. Topic: Evolution can occur through random processes or through selection.Level: mediumConsider a situation in which overharvesting causes the number of fish in a population to become drastically smaller, which causes genetic variation in that fish to decrease over a few generations. This is
29、 an example ofa. bottleneck effect.b. founder effect.c. directional selection.d. recombination.Answer: a21. Topic: Evolution can occur through random processes or through selection.Level: mediumThe four plots in the figure show possible relationships between the survival and beak length in an island
30、 population of birds. Which plot is an example of disruptive selection?a. plot ab. plot bc. plot cd. plot dAnswer: c22. Topic: Evolution can occur through random processes or through selection.Level: mediumStickleback fish exhibit variation in a morphological trait known as gill rakers. Fish with lo
31、ng gill rakers are very good at eating plankton, and fish with short gill rakers are good at eating deep-water invertebrates. However, fish with intermediate-length gill rakers are poor at eating either type of food. Fish that are better at consuming food have higher survival and reproduction rates
32、than poorer consumers. Based on this information, what type of selection is likely acting on stickleback gill raker length?a. no natural selectionb. stabilizing selectionc. disruptive selectiond. directional selectionAnswer: c 23. Topic: Evolution can occur through random processes or through selection.Level: difficultWhen a parental
