Question 1

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing

Accepted Answer

A) nonrandom mating. 
B) geographic isolation. 
C) genetic drift. 
D) gene flow. 
A) nonrandom mating. 
B) geographic isolation. 
C) genetic drift. 
D) gene flow.

Question 2

Which of the following statements is a misconception about evolution of populations?

Accepted Answer

A) Natural selection acts on individuals. 
B) Without genetic variation, evolution would not be possible. 
C) Microevolution is a change in the genetic structure of a population over time. 
D) For a population to evolve, individual members of the population must also evolve. 
E) Most heritable variation involves quantitative characters. 
A) Natural selection acts on individuals. 
B) Without genetic variation, evolution would not be possible. 
C) Microevolution is a change in the genetic structure of a population over time. 
D) For a population to evolve, individual members of the population must also evolve. 
E) Most heritable variation involves quantitative characters.

Question 3

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus

Accepted Answer

A) the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change. 
B) natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency. 
C) this means that, at this locus, two alleles are present in equal proportions. 
D) the population itself is not evolving, but individuals within the population may be evolving. 
A) the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change. 
B) natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency. 
C) this means that, at this locus, two alleles are present in equal proportions. 
D) the population itself is not evolving, but individuals within the population may be evolving.

Question 4

Use the following information to answer the questions below.
In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20% of the β hemoglobin alleles in the human gene pool.
-If the sickle-cell allele is recessive, what proportion of the population should be susceptible to sickle-cell anemia under typical conditions?

Accepted Answer

A) 0.04 
B) 0.16 
C) 0.20 
D) 0.32 
E) 0.80 
A) 0.04 
B) 0.16 
C) 0.20 
D) 0.32 
E) 0.80

Question 5

Hardy-Weinberg equilibrium must occur in populations wherein

Accepted Answer

A) an allele remains fixed. 
B) no genetic variation exists. 
C) natural selection is not operating. 
D) All three of the responses above are correct. 
E) Only two of the responses above are correct. 
A) an allele remains fixed. 
B) no genetic variation exists. 
C) natural selection is not operating. 
D) All three of the responses above are correct. 
E) Only two of the responses above are correct.

Question 6

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the percentage of the population that is heterozygous for this allele?

Accepted Answer

A) 0.2 
B) 2.0 
C) 4.0 
D) 16.0 
E) 32.0 
A) 0.2 
B) 2.0 
C) 4.0 
D) 16.0 
E) 32.0

Question 7

The sickle-cell allele is pleiotropic (i.e., it affects more than one phenotypic trait). Specifically, this allele affects oxygen delivery to tissues and affects one's susceptibility to malaria. Under conditions of low atmospheric oxygen availability, individuals heterozygous for this allele can experience life-threatening sickle-cell "crises." Such individuals remain less susceptible to malaria. Thus, pleiotropic genes/alleles such as this can help explain why

Accepted Answer

A) new advantageous alleles do not arise on demand. 
B) evolution is limited by historical constraints. 
C) adaptations are often compromises. 
D) chance events can affect the evolutionary history of populations. 
A) new advantageous alleles do not arise on demand. 
B) evolution is limited by historical constraints. 
C) adaptations are often compromises. 
D) chance events can affect the evolutionary history of populations.

Question 8

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. Over the course of evolutionary time, what should occur?

Accepted Answer

A) Methylated DNA should become fixed in the gene pools of bacterial species. 
B) Nonmethylated DNA should become fixed in the gene pools of bacteriophages. 
C) Methylated DNA should become fixed in the gene pools of bacteriophages. 
D) Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time. 
E) Both the first and second responses are correct. 
A) Methylated DNA should become fixed in the gene pools of bacterial species. 
B) Nonmethylated DNA should become fixed in the gene pools of bacteriophages. 
C) Methylated DNA should become fixed in the gene pools of bacteriophages. 
D) Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time. 
E) Both the first and second responses are correct.

Question 9

The same gene that causes various coat patterns in wild and domesticated cats also causes the cross-eyed condition in these cats, the cross-eyed condition being slightly maladaptive. In a hypothetical environment, the coat pattern that is associated with crossed eyes is highly adaptive, with the result that both the coat pattern and the cross-eyed condition increase in a feline population over time. Which statement is supported by these observations?

Accepted Answer

A) Evolution is progressive and tends toward a more perfect population. 
B) Phenotype is often the result of compromise. 
C) Natural selection reduces the frequency of maladaptive genes in populations over the course of time. 
D) Polygenic inheritance is generally maladaptive, and should become less common in future generations. 
E) In all environments, coat pattern is a more important survival factor than is eye-muscle tone. 
A) Evolution is progressive and tends toward a more perfect population. 
B) Phenotype is often the result of compromise. 
C) Natural selection reduces the frequency of maladaptive genes in populations over the course of time. 
D) Polygenic inheritance is generally maladaptive, and should become less common in future generations. 
E) In all environments, coat pattern is a more important survival factor than is eye-muscle tone.

Question 10

In the formula for determining a population's genotype frequencies, the pq in the term 2pq is necessary because

Accepted Answer

A) the population is diploid. 
B) heterozygotes can come about in two ways. 
C) the population is doubling in number. 
D) heterozygotes have two alleles. 
A) the population is diploid. 
B) heterozygotes can come about in two ways. 
C) the population is doubling in number. 
D) heterozygotes have two alleles.

Question 11

Which of the following statements about sexual selection is not true?

Accepted Answer

A) Mate (female)choice often leads to exaggerated traits in males. 
B) Sexual selection often results in sexual dimorphism. 
C) Male-male competition is an example of intrasexual selection. 
D) Sexual selection has nothing to do with natural selection because sexual selection is not adaptive. 
E) Evidence suggests that females choose mates based on traits that indicate "good genes." 
A) Mate (female)choice often leads to exaggerated traits in males. 
B) Sexual selection often results in sexual dimorphism. 
C) Male-male competition is an example of intrasexual selection. 
D) Sexual selection has nothing to do with natural selection because sexual selection is not adaptive. 
E) Evidence suggests that females choose mates based on traits that indicate "good genes."

Question 12

Swine are vulnerable to infection by bird flu virus and human flu virus, which can both be present in an individual pig at the same time. When this occurs, it is possible for genes from bird flu virus and human flu virus to be combined, thereby producing a genetically distinctive virus, which can subsequently cause widespread disease. The production of new types of flu virus in the manner described above is most similar to the phenomenon of

Accepted Answer

A) bottleneck effect. 
B) founder effect. 
C) natural selection. 
D) gene flow. 
E) sexual selection. 
A) bottleneck effect. 
B) founder effect. 
C) natural selection. 
D) gene flow. 
E) sexual selection.

Question 13

Use this information below to answer the following questions.
A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants.
-What proportion of the population is probably heterozygous (Aa)for this trait?

Accepted Answer

A) 0.05 
B) 0.25 
C) 0.50 
D) 0.75 
A) 0.05 
B) 0.25 
C) 0.50 
D) 0.75

Question 14

How many of these statements regarding populations are true? 1. Mature males and females of a population can interbreed with each other.
2. Populations are sometimes geographically isolated from other populations.
3. Biological species are made up of populations.
4. Members of a population tend to be genetically more similar to each other than to members of other populations.
5. Populations have genomes, but not gene pools.

Accepted Answer

A) Only one of these statements is true. 
B) Two of these statements are true. 
C) Three of these statements are true. 
D) Four of these statements are true. 
E) All five of these statements are true. 
A) Only one of these statements is true. 
B) Two of these statements are true. 
C) Three of these statements are true. 
D) Four of these statements are true. 
E) All five of these statements are true.

Question 15

During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following terms are appropriately applied to this situation?

Accepted Answer

A) sexual selection 
B) mate choice 
C) intersexual selection 
D) Three of the responses are correct. 
E) Two of the responses are correct. 
A) sexual selection 
B) mate choice 
C) intersexual selection 
D) Three of the responses are correct. 
E) Two of the responses are correct.

Question 16

Rank the following one-base-point mutations (from most likely to least likely)with respect to their likelihood of affecting the structure of the corresponding polypeptide: 1. insertion mutation deep within an intron
2. substitution mutation at the third position of an exonic codon
3. substitution mutation at the second position of an exonic codon
4. deletion mutation within the first exon of the gene

Accepted Answer

A) 1, 2, 3, 4 
B) 4, 3, 2, 1 
C) 2, 1, 4, 3 
D) 3, 1, 4, 2 
E) 2, 3, 1, 4 
A) 1, 2, 3, 4 
B) 4, 3, 2, 1 
C) 2, 1, 4, 3 
D) 3, 1, 4, 2 
E) 2, 3, 1, 4

Question 17

Sexual dimorphism is most often a result of

Accepted Answer

A) pansexual selection. 
B) stabilizing selection. 
C) intrasexual selection. 
D) intersexual selection. 
E) artificial selection. 
A) pansexual selection. 
B) stabilizing selection. 
C) intrasexual selection. 
D) intersexual selection. 
E) artificial selection.

Question 18

Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence?

Accepted Answer

A) mutation 
B) nonrandom mating 
C) genetic drift 
D) natural selection 
E) gene flow 
A) mutation 
B) nonrandom mating 
C) genetic drift 
D) natural selection 
E) gene flow

Question 19

In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?

Accepted Answer

A) disruptive selection 
B) directional selection 
C) stabilizing selection 
D) No selection would operate because the population is in Hardy-Weinberg equilibrium. 
A) disruptive selection 
B) directional selection 
C) stabilizing selection 
D) No selection would operate because the population is in Hardy-Weinberg equilibrium.

Question 20

Swine are vulnerable to infection by bird flu virus and human flu virus, which can both be present in an individual pig at the same time. When this occurs, it is possible for genes from bird flu virus and human flu virus to be combined. If the human flu virus contributes a gene for Tamiflu resistance (Tamiflu is an antiviral drug)to the new virus, and if the new virus is introduced to an environment lacking Tamiflu, then what is most likely to occur?

Accepted Answer

A) The new virus will maintain its Tamiflu-resistance gene, just in case of future exposure to Tamiflu. 
B) The Tamiflu-resistance gene will undergo mutations that convert it into a gene that has a useful function in this environment. 
C) If the Tamiflu-resistance gene involves a cost, it will experience directional selection leading to reduction in its frequency. 
D) If the Tamiflu-resistance gene confers no benefit in the current environment, and has no cost, the virus will become dormant until Tamiflu is present. 
A) The new virus will maintain its Tamiflu-resistance gene, just in case of future exposure to Tamiflu. 
B) The Tamiflu-resistance gene will undergo mutations that convert it into a gene that has a useful function in this environment. 
C) If the Tamiflu-resistance gene involves a cost, it will experience directional selection leading to reduction in its frequency. 
D) If the Tamiflu-resistance gene confers no benefit in the current environment, and has no cost, the virus will become dormant until Tamiflu is present.

Exam 23: The Evolution of Populations

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing

Which of the following statements is a misconception about evolution of populations?

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus

Hardy-Weinberg equilibrium must occur in populations wherein

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the percentage of the population that is heterozygous for this allele?

In the formula for determining a population's genotype frequencies, the pq in the term 2pq is necessary because

Which of the following statements about sexual selection is not true?

During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following terms are appropriately applied to this situation?

Sexual dimorphism is most often a result of

Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence?

In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?

Introduction: Evolution and Themes of Biology

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

Dna Tools and Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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