Presentation on theme: "Biology Ch. 16 Review."— Presentation transcript: 1 Biology Ch. 16 Review Show
2 Which of the following statements describe what all members of a population share? 3 relative frequency. phenotype. genotype. gene pool. 4 Which statement below about gene pools is typically true? 5
If an allele makes up one fourth of a population’s alleles for a given trait, its relative frequency is 100 percent. 75 percent. 25 percent. 4 percent. 6 Interbreeding among members of a population
results in 7 In a population, the sum of the relative frequencies of all alleles for a particular trait is
8 A change in a sequence of DNA is called a
9 The two main sources of genetic variation are
10 In many kinds of organisms, inheritable differences are due mostly to 11 Gene shuffling includes the independent movement of chromosomes during meoisis as well as 12 In a particular population, sexual reproduction can produce 13 The gene shuffling that occurs as part of sexual reproduction 14 A single-gene trait that has two alleles and that shows a
simple dominant-recessive pattern will result in one phenotype. two phenotypes. four phenotypes. millions of phenotypes. 15 An example of a single-gene trait is 16 The number of phenotypes produced for a given trait depends upon 17 The phenotypes for a
typical polygenic trait can often be expressed as 18 Compared to a polygenic trait, a single-gene trait
tends to have 19 A polygenic trait can have 20 Natural selection acts directly on 21 Which of the following is NOT a way in which natural selection affects the distribution of phenotypes? directional
selection stabilizing selection disruptive selection chance events 22 When individuals at only one end of a
bell curve of phenotype frequencies have high fitness, the result is directional selection. stabilizing selection. disruptive selection. genetic drift.
23 When individuals with an average form of a trait have the highest fitness, the result is 24 directional selection disruptive selection stabilizing selection 25 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? how many other alleles are present whether the mutation makes some lizards more fit for their environment than other lizards how many phenotypes the population has whether the
mutation was caused by nature or by human intervention 26 In genetic drift, allele frequencies change because of
27 Which of the following events do biologists consider a random change?
28 Genetic drift tends to occur in populations that
29 The type of genetic drift that follows the colonization of a new habitat by a small group of individuals is called the Hardy-Weinberg
principle. the founder effect. directional selection. stabilizing selection. 30 One similarity between natural selection and genetic drift is that both
events
31 The situation in which allele frequencies of a population remain constant is called 32 One of the conditions required to maintain genetic equilibrium is
33 The genetic equilibrium of a population can be disturbed by each of the following EXCEPT 34 The allele frequencies of a population are more likely to remain unchanged if 35 According to the
Hardy-Weinberg principle, genetic equilibrium would be more likely in a population of mice if the population size rapidly decreases. mutation rates within the population rise. no natural selection takes place. there is frequent movement into and out of the population.
36 Which factor would most likely disrupt genetic equilibrium in a large population? 37 The separation of populations by barriers such as rivers, mountains, or bodies of water is
called 38 A factor that is necessary for the formation of a new species
is
39 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? behavioral isolation geographic isolation temporal isolation genetic drift 40 The geographic isolation of two populations of a species tends to increase differences between their gene pools because it prevents interbreeding between the populations. prevents interbreeding within each population. causes temporal isolation of the two populations. increases differences in courtship behavior.
41 Although they often live in the same habitat, the
American toad breeds earlier in the spring than the Fowler’s toad does. What can be inferred from this information? The two species do not interbreed because of geographic isolation. The two species do not interbreed because of temporal isolation. The two species interbreed throughout the spring season. The American toad will cause the extinction of the Fowler’s toad.
42 Which is the first step that occurred in the speciation of the Galápagos finches? 43 The Galápagos finch species are an excellent example of 44 What did Peter and Rosemary Grant learn about mate choice from the Galápagos finches?
45 In Rosemary and Peter Grant’s study of the Galápagos finches, what process was encouraged by
ecological competition during the dry season? stabilizing selection disruptive selection directional selection genetic drift 46 Which statement about evolution in the Galápagos
finches is true?
47 Because all members of a population can interbreed, biologists often study their genes as a single group. True False
48 In a gene pool, as the relative frequency of one allele for a trait increases, the relative
frequencies of other alleles for that trait decrease. True False 49 Most inheritable differences are due to mutations that occur during the
production of gametes. 50 Mutations do not always affect an organism’s
genotype—its physical, behavioral, and biochemical characteristics. True False 51 A polygenic trait is controlled by one gene.
52 On a graph, the distribution of phenotypes for a single-gene trait tends to form a bell-shaped curve. True False
53 Natural selection on single-gene traits can lead to changes in allele frequencies.
54 In a population of snakes with a range of body lengths, if the longest individuals
have the highest fitness, disruptive selection is likely to occur. True False 55 In small populations, an allele can become more or less common simply by
chance. 56 Genetic drift may occur when a small group of individuals colonize a new habitat.
57 When mutations introduce new alleles into a population, genetic variation is disrupted.
58 In a population of birds, if females
prefer males with long tails, the population violates the condition of directional selection described by the Hardy-Weinberg principle. True False
59 In the type of reproductive isolation called behavioral isolation, two populations are separated by barriers
such as rivers or mountains. True False 60
Two populations that have overlapping ranges can remain reproductively isolated through behavioral isolation or temporal isolation from each other. True False
61 The first step of the speciation of the Galápagos finches likely was the arrival of founders from South America. True False
Which of the following can disrupt genetic equilibrium?The Hardy-Weinberg equilibrium can be disturbed by a number of forces, including mutations, natural selection, nonrandom mating, genetic drift, and gene flow. For instance, mutations disrupt the equilibrium of allele frequencies by introducing new alleles into a population.
What are the 5 principles that can disturb genetic equilibrium?In order for a population to be in Hardy-Weinberg equilibrium, or a non-evolving state, it must meet five major assumptions:. No mutation. No new alleles are generated by mutation, nor are genes duplicated or deleted.. Random mating. ... . No gene flow. ... . Very large population size. ... . No natural selection.. What are the factors that affect the genetic equilibrium in a population?Mutations, recombinations during sexual reproduction, genetic drift, gene migration or gene flow, and natural selection are the major factors that influence genetic equilibrium and cause variety in the population.
Which of the following does not disturb HardyIt does not specifically selection for traits that are fit for the environment. Hence, answer is "Genetic drift"
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