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Chapter 23: The Evolution of Populations
 
Chapter Quiz
 

Chapter Quiz


1 .       The major addition of the modern synthesis to Darwin's theory is the idea that _____. (Concept 23.1E-Book) [Hint]

 evolution is a change in a population's allelic frequencies
 within a population, some individuals leave more offspring than others
 sexual reproduction can rapidly spread advantageous traits
 human-made stresses, such as radiation and pollution, are the major selective forces in nature
 all of the above
2 .       According to the modern synthesis of evolutionary theory, which of the following is true? (Concept 23.1E-Book) [Hint]

 Populations are the units of evolution.
 Only certain animal species participate in sexual reproduction.
 Evolution is independent of genetics.
 Segregation and independent assortment explain evolution of the individual, not the species.
 All of the above.
3 .       In a large population of randomly breeding organisms, the frequency of a recessive allele is initially 0.3. There is no migration and no selection. Humans enter this ecosystem and selectively hunt individuals showing the dominant trait. When the gene frequency is reexamined at the end of the year, _____. (Concept 23.1E-Book) [Hint]

 the frequency of the homozygous dominants will go down, the frequency of the heterozygous genotype will go up, and the frequency of the homozygous recessives will remain the same
 the frequency of the homozygous dominants will go down, the frequency of the heterozygous genotype will remain the same, and the frequency of the homozygous recessives will go up
 the frequency of the homozygous dominants will go up, the frequency of the heterozygous genotype will go down, and the frequency of the homozygous recessives will go down
 the frequency of the homozygous dominants will go up, the frequency of the heterozygous genotype will go down, and the frequency of the homozygous recessives will go up
 the frequency of the individuals who express the dominant phenotype will go down and the frequency of homozygous recessive individuals will go up
4 .       In the Hardy-Weinberg theorem, p2 represents _____. (Concept 23.1E-Book) [Hint]

 the total alleles in the gene pool
 the frequency of heterozygous dominants in the gene pool
 the frequency of homozygous recessives in the gene pool
 all of the possible phenotypes in the gene pool
 the frequency of homozygous dominants in the gene pool
5 .       In a large population of bonobos, the frequency of the recessive allele is initially 0.1. There is no migration and no selection. What is the frequency of the dominant allele? Assume that there are two alleles of this gene. (Concept 23.1E-Book) [Hint]

 10%
 20%
 50%
 90%
 99%
6 .       In a population in Hardy-Weinberg equilibrium, 1% of the individuals in a population show the recessive trait of a certain characteristic. In this situation, what is the value of p? (Concept 23.1E-Book) [Hint]

 99%
 0.81
 0.9
 0.18
 The answer cannot be determined from the information given.


7 .       In the Hardy-Weinberg theorem, 1 represents _____. (Concept 23.1E-Book) [Hint]

 the sum of the frequencies of all the alleles of a particular gene that exists in a gene pool
 the frequency of heterozygous dominants in the gene pool
 the frequency of homozygous recessives in the gene pool
 all the possible phenotypes in the gene pool
 the frequency of homozygous dominants in the gene pool
8 .       Approximately 1 out of every 2,500 Caucasians in the United States is born with the recessive disease cystic fibrosis. According to the Hardy-Weinberg equilibrium equation, approximately how many people are carriers? (Concept 23.1E-Book) [Hint]

 about 1 in 50
 about 96 in 100
 about 1 in 25
 about 1 in 10
 none of the above
9 .       In a certain group of African people, 4% are born with sickle-cell disease (homozygous recessive). If this group is in Hardy-Weinberg equilibrium, what percentage of the group has the selective advantage of being more resistant to malaria (heterozygous) than those individuals who are homozygous for normal hemoglobin or for sickle-cell disease? (Concept 23.1E-Book) [Hint]

 2%
 4%
 8%
 16%
 32%
10 .       Assume a population in Hardy-Weinberg equilibrium for a character trait with these genotypic frequencies: AA = 0.25, Aa = 0.50, and aa = 0.25. If you remove all the homozygous dominants and allow the remaining population to reproduce (again under Hardy-Weinberg conditions), what will be the frequency of homozygous dominants in the next generation? (Concept 23.1E-Book) [Hint]

 0
 0.11
 0.22
 0.44
 0.50
11 .       Which of the following conditions is not required for Hardy-Weinberg equilibrium? (Concept 23.1E-Book) [Hint]

 a large population
 no migration of alleles in or out of the population
 no mutations altering the gene pool
 sexual selection
 random mating
12 .       New alleles originate from _____. (Concept 23.2E-Book) [Hint]

 natural selection
 genetic drift
 sexual recombination
 the environment
 mutation
13 .       _____ and _____ generate variation, while _____ results in an adaptation to the environment. (Concept 23.2E-Book) [Hint]

 Genetic drift ... natural selection ... mutation
 Mutation ... sexual recombination ... natural selection
 Overproduction of offspring ... mutation ... sexual recombination
 Natural selection ... mutation ... sexual recombination
 Sexual recombination ... natural selection ... overproduction
14 .       Which type of mutation plays the most important role in increasing the number of genes in the gene pool? (Concept 23.2E-Book) [Hint]

 Mutations are so rare that there are no mutations that can have such an important effect.
 duplication
 point mutation
 rearrangement of gene loci
 changes in nucleotide sequence
15 .       Sexual recombination includes the shuffling of chromosomes in _____ and fertilization. (Concept 23.2E-Book) [Hint]

 mitosis
 genetic drift
 natural selection
 mutation
 meiosis
16 .       A population of 15 birds inhabits a fairly new island. Ten of the birds are dark-brown and five of them are light brown. By chance, two of the dark brown birds and three of the light-brown birds die before producing any offspring. All of the birds in the next generation are dark brown. This change in phenotypic frequency can be attributed to _____. (Concept 23.3E-Book) [Hint]

 natural selection
 genetic drift
 gene flow
 disruptive selection
 a cline
17 .       An earthquake hits a small island. All but a small group of closely related lizards are eliminated, and the survivors spread out over the island. This is an instance of _____. (Concept 23.3E-Book) [Hint]

 founder effect
 bottleneck effect
 gene flow
 mutation
 nonrandom mating
18 .       Which of the following scenarios would most likely result in the microevolution of a population of humans? (Concept 23.2E-Book) [Hint]

 Only random mating takes place among all the people that reproduce in North America.
 A colony of humans on the moon is isolated from Earth.
 The incidence of skin cancer in adults over age 40 rises significantly.
 Hundreds of thousands of people are killed in a natural disaster.
 Both random mating and an increase in middle-aged skin cancer occur.
19 .       Which of the following is the best example of gene flow? (Concept 23.3E-Book) [Hint]

 A small population of humans colonizes a newly formed island.
 Genes are shuffled by the crossing over of chromosomes during meiosis.
 An earthquake results in the formation of a canyon, splitting a population of toads apart.
 Wind blows pollen from one population of plants to another and cross-fertilization occurs.
 All the mutations in a population were neutral.
20 .       Which example below correctly describes average heterozygosity? (Concept 23.4E-Book) [Hint]

 Average heterozygosity refers to the number of individuals in a population that are heterozygous for a certain trait.
 Average heterozygosity is measured by comparing the nucleotide sequences of DNA samples, and then averaging the data from the comparison.
 Average heterozygosity is usually less than the average difference between nucleotide sequences.
 Average heterozygosity refers to the average percentage of loci that are heterozygous in a population.
 Human populations have an average heterozygosity of 0.1%.


21 .       Which example below would most likely be a cline? (Concept 23.4E-Book) [Hint]

 Individuals who are heterozygotic for the sickle-cell disease allele have a greater resistance to malaria.
 Rabbits that live in colder regions tend to have smaller ears than rabbits of the same species that live in warmer regions.
 Male bowerbirds decorate stations to attract females.
 Cows are selectively bred to gain a higher milk yield.
 Seals have flippers that make them great swimmers but make their movements on rocks and land very cumbersome.


22 .       Which of the following most accurately measures an organism's fitness? (Concept 23.4E-Book) [Hint]

 how strong the organism is when pitted against others of its species
 its mutation rate
 how many fertile offspring it produces
 its ability to withstand environmental extremes
 how much food it is able to make or obtain
23 .       Antibiotic resistance in bacteria is an example of which of the following? (Concept 23.4E-Book) [Hint]

 stabilizing selection
 directional selection
 disruptive selection
 Hardy-Weinberg equilibrium
 macroevolution
24 .       For several years, scientists have warned doctors of the danger of overprescribing antibiotics such as penicillin. Scientists are concerned because _____. (Concept 23.4E-Book) [Hint]

 humans will become tolerant to the effects of drugs
 the organisms that produce many of the antibiotics are overexploited and could become extinct
 strains of microorganisms that are resistant to these drugs will be selected for
 the drugs will be metabolized more quickly by our bodies, decreasing their effectiveness
 none of these
25 .       A population of squirrels is preyed upon by small hawks. The smaller squirrels can escape into burrows. The larger squirrels can fight off the hawks. After several generations, the squirrels in the area tend to be very small or very large. What process is responsible for this outcome? (Concept 23.4E-Book) [Hint]

 stabilizing selection
 directional selection
 disruptive selection
 balancing selection
 Hardy-Weinberg equilibrium
26 .       Stabilizing selection _____. (Concept 23.4E-Book) [Hint]

 favors intermediate variants in a population
 prevents mutations from occurring
 occurs when some individuals migrate to an area with different environmental conditions
 can take place only in species exhibiting sexual dimorphism
 occurs only in plants
27 .       Birds with average-size wings survived a severe storm more successfully than other birds in the same population with longer or shorter wings. If severe storms occur regularly, then over time, one should expect these storms to bring about _____. (Concept 23.4E-Book) [Hint]

 the bottleneck effect
 stabilizing selection
 artificial selection
 gene flow
 disruptive selection
28 .       Tay-Sachs disease, which is lethal, results from having the homozygous recessive condition of the responsible gene. Which one of the following statements is true? (Concept 23.4E-Book) [Hint]

 Because homozygous recessive individuals die, the recessive allele will eventually be lost from the population.
 Only homozygous dominant individuals will be able to survive and reproduce.
 Heterozygous individuals will survive and may pass the recessive allele on to their offspring.
 In the heterozygous condition, the dominant allele will overcome the recessive allele and only the dominant allele will be passed on to offspring.
 Homozygous dominant individuals will be more likely to reproduce than heterozygous individuals.
29 .       Which type of selection maintains stable frequencies of two or more phenotypic forms in a population? (Concept 23.4E-Book) [Hint]

 balancing selection
 neutral variation
 heterozygote advantage
 stabilizing selection
 relative fitness


30 .       Which of the following would seem to be an example of neutral variation? (Concept 23.4E-Book) [Hint]

 homozygosity of the cheetah population
 polymorphism of the Galápagos finches
 founder effect
 human fingerprints
 moth coloration
31 .       Which statement below is not true about neutral variation? (Concept 23.4E-Book) [Hint]

 A variant allele may be neutral in one environment, but not in another.
 Even mutational changes that alter proteins can be neutral.
 Relative frequencies of neutral variations are controlled by natural selection.
 It is difficult to determine whether a variation is neutral because detrimental effects are usually much more apparent than beneficial ones.
 All of the above statements are true.


32 .       Selection that acts over evolutionary time to preserve traits that increase an individual's ability to mate is known as _____. (Concept 23.4E-Book) [Hint]

 directional selection
 disruptive selection
 stabilizing selection
 sexual selection
 balancing selection
33 .       Which statement below is true about sexual selection? (Concept 23.4E-Book) [Hint]

 Intrasexual selection leads to the death of most unfit males in combat.
 Showy secondary sexual characteristics cannot be explained because they break all of the rules of natural selection.
 In most vertebrates, females court the males.
 There is no evidence that intrasexual selection takes place between females.
 Sexual dimorphism is the term that describes marked differences between the sexes in secondary sexual characteristics that are not associated directly with reproduction.


34 .       Which statement below about sexual reproduction is true? (Concept 23.4E-Book) [Hint]

 As a mechanism of population expansion, sexual reproduction is superior to asexual reproduction.
 Sexual reproduction cannot promote genetic variation on a generation-to-generation time scale.
 Some researchers think that natural selection favors sexual reproduction because genetic variation is important in resistance to disease.
 Natural selection sustains sexual reproduction alleles because genetic variation enables future adaptations to dynamic environments.
 None of the above statements are true.


35 .       A number of mosquito populations today are resistant to insecticides that were once quite effective. Biologists think that insecticide resistance evolved in mosquitoes because _____. (Concept 23.4E-Book) [Hint]

 individual mosquitoes built up an immunity to an insecticide after being exposed to it
 mosquitoes needed to develop insecticide resistance to survive after the insecticide was used
 a few mosquitoes were probably resistant to the insecticide before it was ever used, and these individuals were more likely to survive and reproduce
 mosquitoes attempted to adapt to their environment
 a new allele developed in response to the insecticide that provided future generations the benefit of resistance





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