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Chapter 9
The graph below shows the chromosomal variation in the natural populations of Drosophila pseudoobscura studied by Dobzhansky. Which of the following conclusions follows from the data in the graph? a. On average, heterozygotes have lower viability than homozygotes. b. Many recessive alleles severely reduce viability and survival when homozygous. c. Deleterious mutations are rare. d. The distribution of homozygote viability is unimodal. e. All mutations are deleterious. Incorrect Correct Answer: b Your Answer: Did not answer Textbook Reference: Genetic Variation in Natural Populations: Individual Genes
Which of the following observations about a population would not violate the assumptions of the Hardy–Weinberg principle? a. UV radiation induces new mutations at a high frequency. b. Individuals migrate from nearby populations but die prior to breeding. c. Cold tolerance differs by genotype, and the population experiences a frost. d. Inbreeding is present. e. The population size is smaller than 100 individuals. Incorrect Correct Answer: b Your Answer: Did not answer Textbook Reference: Understanding Evolution: Fundamental Principles of Genetic Variation The graph below represents the mortality rate of offspring from marriages registered in 1903– 1907 in Italian populations. The data indicate that the offspring of related individuals have higher mortality rates. What is a likely cause of this inbreeding depression? a. Close relatives are more likely to neglect their children b. Italian populations are more likely than other populations to have genetic diseases. c. Inbred individuals are more likely than other individuals to be homozygous for deleterious recessive alleles. d. The offspring of close relatives are born at a larger size than other offspring.
If 23 geese in a population of 142 are white and 119 are blue, how many of the blue geese would you expect to be carriers of the b allele (i.e., Bb heterozygotes)? a. 57 b. 68 c. 85 d. 51 e. 71 Incorrect Correct Answer: b Your Answer: Did not answer Textbook Reference: Understanding Evolution: Fundamental Principles of Genetic Variation Nonrandom associations between alleles at different loci are referred to by which of the following terms? a. Heterozygosity b. Linkage equilibrium c. Inbreeding depression d. Panmictic e. Linkage disequilibrium Incorrect Correct Answer: e Your Answer: Did not answer Textbook Reference: Genetic Variation in Natural Populations: Multiple Loci The graph below shows the frequency distribution for a particular trait (number of dermal ridges) in a sample of British men.
Many such quantitative traits have a normal distribution. What is a likely cause of this? a. Statistical noise b. Single-gene effects c. Many traits are polygenic and the effects of alleles are additive d. Mutation e. Genotype × environment interaction Incorrect Correct Answer: c Your Answer: Did not answer Textbook Reference: Genetic Variation in Natural Populations: Multiple Loci Phenotypic differences that are not based on DNA sequence differences (for example, DNA methylation) can be passed from parent to offspring. This phenomenon is called a. genotype x environment interaction. b. maternal effects. c. epigenetic inheritance. d. phenotypic plasticity. e. norm of reaction. Incorrect Correct Answer: c Your Answer: Did not answer
Textbook Reference: Sources of Phenotypic Variation The figure below shows that high levels of DNA sequence variation are observed at the Adh locus in Drosophila melanogaster. Based on this observation, which of the following conclusions would be false? a. Multiple alleles exist for the Adh locus. b. DNA sequence information at this locus has been influenced by demography and natural selection. c. Other loci exhibit similar levels of variation. d. Genetic variation can be detected via multiple techniques. e. DNA sequence polymorphisms occur only within introns. Incorrect Correct Answer: e Your Answer: Did not answer Textbook Reference: Genetic Variation in Natural Populations: Individual Genes The graph below plots heterozygosity for a variety of human populations.
The data in this graph support a. Bergmann’s Rule. b. Cope’s Rule. c. The Hardy-Weinberg principle. d. The “multi-regional” hypothesis. e. The “out of Africa” hypothesis. Incorrect Correct Answer: e Your Answer: Did not answer Textbook Reference: Variations among Populations A population of prairie chickens has recently undergone a reduction in population size, and inbred matings are now common. If this population is observed in the next few generations, one would expect to see which of the following patterns? (Assume that natural selection is absent.) a. Heterozygosity decreasing over time, with greater changes occurring in the first few generations b. Heterozygosity decreasing over time, with greater changes occurring in later generations
a. 1. b. 0. c. 0. d. 0. e. 0. Incorrect Correct Answer: c Your Answer: Did not answer Textbook Reference: Genetic Variation in Natural Populations: Multiple Loci
Chapter 10
Which of the following is not a reason that an effective population size can be smaller than the actual population size? a. There are different numbers of males and females in the population. b. Every individual produces exactly two offspring. c. Generations overlap. d. There is natural selection (a high variance in the number of offspring). e. Population size fluctuates. Incorrect Correct Answer: b Your Answer: Did not answer Textbook Reference: Evolution by Genetic Drift Two alleles ( A and B ) segregate at a locus. Assuming that no stabilizing forces exist, the A allele will eventually be a. fixed. b. either lost or found. c. preserved. d. either fixed or broken. e. either lost or fixed. Incorrect Correct Answer: e Your Answer: Did not answer Textbook Reference: The Theory of Genetic Drift A small population of three-spined stickleback fish lives in an Alaskan lake. Two alleles segregate at a neutral locus ( A and B ). The allele frequency of the A allele is 0.78. Which of the following allele frequencies would most likely be found in the next generation? a. 0. b. 0. c. 0. d. 0. e. 0. Incorrect
b. Hunting in the 1890s selected for clever seals. c. The population experienced a bottleneck. d. Both a and b e. Both a and c Incorrect Correct Answer: e Your Answer: Did not answer Textbook Reference: Evolution by Genetic Drift Which of the following is not a good explanation for why rates of molecular evolution vary between lineages? a. Genes evolve more slowly in organisms with long generation times. b. Mutation rates vary for organisms with different metabolic rates. c. Natural selection acts equally on sequence variation in all parts of the genome. d. Variation in effective population sizes leads to variation in the rate that genetic differences accumulate. e. All of the above are good explanations. Incorrect Correct Answer: c Your Answer: Did not answer Textbook Reference: The Neutral Theory of Molecular Evolution A set of 107 experimental populations of Drosophila melanogaster were maintained at a population size of 16 individuals for multiple generations. In each population, the initial frequencies of bw^75 and bw alleles were equal. After 19 generations, the bw^75 was fixed in 28 populations and lost in 30 populations. Results are shown in the figure below.
These results suggest that a. both alleles are neutral, and fixation events were due to genetic drift. b. the bw^75 allele has a higher fitness than the bw allele, and fixation events were due to genetic drift. c. the bw^75 allele has a higher fitness than the bw allele, and fixation events were due to natural selection. d. both alleles are neutral, and fixation events were due to natural selection. e. a population size of 16 individuals is too small to display the effects of genetic drift. Incorrect Correct Answer: a Your Answer: Did not answer Textbook Reference: Evolution by Genetic Drift Which of the following statements about genetic drift is true? a. Mildly disadvantageous alleles can sometimes increase in frequency, due to genetic drift. b. Evolution by random genetic drift proceeds faster in large populations than in small
F ST is a measure of population differentiation. An equation exists for the equilibrium F ST when the forces of drift and mutation counteract each other. Which of the following statements about this equation is false? a. If rates of migration are high, then at equilibrium, F ST will be low. b. Gene flow causes demes to differ, while genetic drift causes demes to be similar. c. F ST levels can be used to estimate migration rates. d. If rates of migration are low, then at equilibrium, F ST will be high. e. If population sizes are large, F ST will be low. Incorrect Correct Answer: b Your Answer: Did not answer Textbook Reference: Gene Flow and Genetic Drift Natural selection and genetic drift are the two most important causes of evolutionary change. How do they differ? a. Only natural selection can change the frequencies of alleles in a population. b. Genetic drift is nonadaptive; it changes allele frequency without regard to fitness. c. Only genetic drift has been observed in populations of finite size. d. Natural selection involves a population moving toward a goal, while genetic drift is not directed. e. Natural selection focuses on the survival of individuals, while genetic drift refers to which individuals actually reproduce Incorrect Correct Answer: b Your Answer: Did not answer Textbook Reference: Random Processes in Evolution Human mtDNA lineages coalesced over a hundred thousand years ago (156 to 250 Kya) in a putative individual who has been dubbed “mitochondrial Eve.” What does this name mean? a. The human population at the time had only one female. b. The name “Eve” first appeared in the historical record over a hundred thousand years ago. c. Genetic drift does not affect coalescent times. d. There are many origins for modern Homo sapiens. e. Other females lived at the time, but their mtDNA is absent from today’s population. Incorrect Correct Answer: e
Your Answer: Did not answer Textbook Reference: The Theory of Genetic Drift Consider a hypothetical locus with two segregating alleles ( A and B ). Population size is small, mutation is absent, and neither of the two alleles has a selective advantage. Which of the following is likely to occur after a long period of time (many generations)? a. Allele frequencies will change over time, but both alleles will remain. b. Allele frequencies will remain constant. c. Balancing selection will maintain both alleles. d. Allele frequencies will cycle over time. e. The population will eventually become monomorphic for one of the two alleles. Incorrect Correct Answer: e Your Answer: Did not answer Textbook Reference: The Theory of Genetic Drift
Your Answer: Did not answer Textbook Reference: Adaptations in Action: Some Examples Meiotic drive, or segregation distortion, is an example of a. sexual selection. b. kin selection. c. group selection. d. gametic selection. e. inclusive fitness. Incorrect Correct Answer: d Your Answer: Did not answer Textbook Reference: Examples of Natural Selection An experiment shows (1) that the size of a population may decline as a result of natural selection, even as individual organisms become fitter, and (2) that selection for larger groups opposes the consequences of individual selection. These observations provide evidence for a. the influence of altruistic traits. b. the process of group selection. c. the effects of individual selection. d. Both b and c e. All of the above Incorrect Correct Answer: d Your Answer: Did not answer Textbook Reference: Examples of Natural Selection Which of the following statements about adaptations is false? a. They enhance fitness. b. They evolve through natural selection. c. They perform a function. d. They arose when the current function arose. e. They are developed by individuals in response to the needs of the individual. Incorrect Correct Answer: e
Your Answer: Did not answer Textbook Reference: What Not to Expect of Natural Selection and Adaptation Species selection occurs when there is a correlation between some trait and the rates of two processes: _______ and _______. a. survival; reproduction b. geological duration; geographic range c. speciation; extinction d. fitness; heritability e. sexual reproduction; asexual reproduction Incorrect Correct Answer: c Your Answer: Did not answer Textbook Reference: Levels of Selection Which of the following would be the best way to test whether larger body size in amphipods is an adaptation to risk of predation? a. Correlate body size with predation risk across a number of closely related species, independent of phylogenetic relationships. b. Correlate body size with predation risk across a number of closely related species, taking into account phylogenetic relationships. c. Expose two species that differ in body size to predators, and compare their survivorship. d. Expose all of the closely related species to predators and compare their survivorship. e. Correlate body size with other possible antipredator traits, such as armor or swimming speed. Incorrect Correct Answer: b Your Answer: Did not answer Textbook Reference: The Nature of Adaptations The fitness of a biological entity is a. the variation in the number of offspring produced as a consequence of competition for mates. b. any consistent difference in reproductive success among phenotypically different classes of organisms. c. its survival rate. d. its average per capita rate of increase in numbers. e. its physiological condition.
