Question 1

The most likely explanation for the recent decline in cichlid species diversity in Lake Victoria is

Accepted Answer

A) reinforcement. 
B) fusion. 
C) stability. 
D) geographic isolation. 
E) polyploidy. 
A) reinforcement. 
B) fusion. 
C) stability. 
D) geographic isolation. 
E) polyploidy. B

Question 2

The next few questions refer to the following description.
On the volcanic equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 320 kilometres away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago.
-Using only the information provided in the description, which of the following is the best initial hypothesis for how D. santomea descended from D. yakuba?

Accepted Answer

A) geographic isolation 
B) autopolyploidy 
C) habitat differentiation 
D) sexual selection 
E) allopolyploidy 
A) geographic isolation 
B) autopolyploidy 
C) habitat differentiation 
D) sexual selection 
E) allopolyploidy C

Question 3

The next few questions refer to the following description.
On the volcanic equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 320 kilometres away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago.
-Which of the following reduces gene flow between the gene pools of the two species on Sao Tomé, despite the existence of hybrids?

Accepted Answer

A) hybrid breakdown 
B) hybrid inviability 
C) hybrid sterility 
D) temporal isolation 
E) a geographic barrier 
A) hybrid breakdown 
B) hybrid inviability 
C) hybrid sterility 
D) temporal isolation 
E) a geographic barrier C

Question 4

Suppose that a group of male pied flycatchers migrated from a region where there were no collared flycatchers to a region where both species were present. Assuming events like this are very rare, which of the following scenarios is least likely?

Accepted Answer

A) The frequency of hybrid offspring would increase. 
B) Migrant pied males would produce fewer offspring than would resident pied males. 
C) Pied females would rarely mate with collared males. 
D) Migrant males would mate with collared females more often than with pied females. 
E) The frequency of hybrid offspring would decrease. 
A) The frequency of hybrid offspring would increase. 
B) Migrant pied males would produce fewer offspring than would resident pied males. 
C) Pied females would rarely mate with collared males. 
D) Migrant males would mate with collared females more often than with pied females. 
E) The frequency of hybrid offspring would decrease.

Question 5

In order for speciation to occur, what must be true?

Accepted Answer

A) The number of chromosomes in the gene pool must change. 
B) Changes to centromere location or chromosome size must occur within the gene pool. 
C) Large numbers of genes that affect a single phenotypic trait must change. 
D) Large numbers of genes that affect numerous phenotypic traits must change. 
E) At least one gene, affecting at least one phenotypic trait, must change. 
A) The number of chromosomes in the gene pool must change. 
B) Changes to centromere location or chromosome size must occur within the gene pool. 
C) Large numbers of genes that affect a single phenotypic trait must change. 
D) Large numbers of genes that affect numerous phenotypic traits must change. 
E) At least one gene, affecting at least one phenotypic trait, must change.

Question 6

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

Accepted Answer

A) reduced hybrid fertility 
B) hybrid breakdown 
C) mechanical isolation 
D) habitat isolation 
E) gametic isolation 
A) reduced hybrid fertility 
B) hybrid breakdown 
C) mechanical isolation 
D) habitat isolation 
E) gametic isolation

Question 7

The next few questions refer to the following evolutionary tree, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change.
  
-Which species is least expected to have a good record of transitional fossils; in other words, which species' fossils, if present at all, are expected only in relatively superficial (i.e., shallow)strata?

Accepted Answer

A) V 
B) W 
C) X 
D) Y 
E) Z 
A) V 
B) W 
C) X 
D) Y 
E) Z

Question 8

Which of the following statements about speciation is correct?

Accepted Answer

A) The goal of natural selection is speciation. 
B) When reunited, two allopatric populations will interbreed freely if speciation has occurred. 
C) Natural selection chooses the reproductive barriers for populations. 
D) Prezygotic reproductive barriers usually evolve before postzygotic barriers. 
E) Speciation is a basis for understanding macroevolution. 
A) The goal of natural selection is speciation. 
B) When reunited, two allopatric populations will interbreed freely if speciation has occurred. 
C) Natural selection chooses the reproductive barriers for populations. 
D) Prezygotic reproductive barriers usually evolve before postzygotic barriers. 
E) Speciation is a basis for understanding macroevolution.

Question 9

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification?

Accepted Answer

A) The two forms interbreed often in nature, and their offspring have good survival and reproduction. 
B) The two forms live in similar habitats. 
C) The two forms have many genes in common. 
D) The two forms have similar food requirements. 
E) The two forms are very similar in colouration. 
A) The two forms interbreed often in nature, and their offspring have good survival and reproduction. 
B) The two forms live in similar habitats. 
C) The two forms have many genes in common. 
D) The two forms have similar food requirements. 
E) The two forms are very similar in colouration.

Question 10

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In rangelands of the western United States, pronghorns and cattle often associate with one another. If some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood, then over time which of these should occur, if the host mammal can be considered as the fleas' habitat? 1. reproductive isolation
2. sympatric speciation
3. habitat isolation
4. prezygotic barriers

Accepted Answer

A) 1 only 
B) 2 and 3 
C) 1, 2, and 3 
D) 2, 3, and 4 
E) 1 through 4 
A) 1 only 
B) 2 and 3 
C) 1, 2, and 3 
D) 2, 3, and 4 
E) 1 through 4

Question 11

The next few questions refer to the following description.
On the volcanic equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 320 kilometres away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago.
-Which of these evolutionary trees represents the situation in the description? (Note: Yakuba (I)represents the island population, and yakuba (M)represents the mainland population.)

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 12

Speciation can reveal traits that cause reproductive isolation. These traits

Accepted Answer

A) can include a change in one gene or in a small number of genes. 
B) can include a change in a large number of genes and gene interactions. 
C) don't depend on genetic variation as long as geographic variation is maintained. 
D) depend on sexual selection. 
E) A and B 
A) can include a change in one gene or in a small number of genes. 
B) can include a change in a large number of genes and gene interactions. 
C) don't depend on genetic variation as long as geographic variation is maintained. 
D) depend on sexual selection. 
E) A and B

Question 13

The next few questions refer to the following evolutionary tree, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change.
  
-Which of these five species is the extant (i.e., not extinct)species that is most closely related to species X, and why is this so?

Accepted Answer

A) V; shared a common ancestor with X most recently 
B) W; shared a common ancestor with X most recently 
C) Y; arose in the same fashion (i.e., at the same tempo)as X 
D) Z; shared a common ancestor with X most recently, and arose in the same fashion as X 
E) This tree does not provide enough information to answer this question. 
A) V; shared a common ancestor with X most recently 
B) W; shared a common ancestor with X most recently 
C) Y; arose in the same fashion (i.e., at the same tempo)as X 
D) Z; shared a common ancestor with X most recently, and arose in the same fashion as X 
E) This tree does not provide enough information to answer this question.

Question 14

The next few questions refer to the following description.
In the ocean, on either side of the Isthmus of Panama, are 30 species of snapping shrimp; some are shallow-water species, others are adapted to deep water. There are 15 species on the Pacific side and 15 different species on the Atlantic side. The Isthmus of Panama started rising about 10 million years ago.
In the following figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The sea water on either side of the isthmus is separated into five depth habitats (1-5), with 1 being the shallowest.
  
-Which factor is most important for explaining why there are equal numbers of snapping shrimp species on either side of the isthmus?

Accepted Answer

A) the relative shortness of time they have been separated 
B) the depth of the ocean 
C) the number of actual depth habitats between the surface and the sea floor 
D) the elevation of the isthmus above sea level 
E) the depth of the canal 
A) the relative shortness of time they have been separated 
B) the depth of the ocean 
C) the number of actual depth habitats between the surface and the sea floor 
D) the elevation of the isthmus above sea level 
E) the depth of the canal

Question 15

The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of

Accepted Answer

A) allopatric speciation. 
B) sympatric speciation. 
C) autopolyploidy. 
D) habitat selection. 
A) allopatric speciation. 
B) sympatric speciation. 
C) autopolyploidy. 
D) habitat selection.

Question 16

The next few questions refer to the following evolutionary tree, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change.
  
-Which conclusion can be drawn from this evolutionary tree?

Accepted Answer

A) Gradualistic speciation and speciation involving punctuated equilibrium are mutually exclusive concepts; only one of them can occur. 
B) Eldredge and Gould would deny that the lineages labelled X, Y, and Z could represent true species. 
C) Assuming that the tip of each line represents a species, there are five extant (i.e., not extinct)species resulting from the earliest common ancestor. 
D) A single clade (i.e., a group of species that share a common ancestor)can exhibit both gradualism and punctuated equilibrium. 
E) V and W shared a common ancestor more recently than any of the other species. 
A) Gradualistic speciation and speciation involving punctuated equilibrium are mutually exclusive concepts; only one of them can occur. 
B) Eldredge and Gould would deny that the lineages labelled X, Y, and Z could represent true species. 
C) Assuming that the tip of each line represents a species, there are five extant (i.e., not extinct)species resulting from the earliest common ancestor. 
D) A single clade (i.e., a group of species that share a common ancestor)can exhibit both gradualism and punctuated equilibrium. 
E) V and W shared a common ancestor more recently than any of the other species.

Question 17

The next few questions refer to the following evolutionary tree, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change.
  
-Which of these five species originated earliest and appeared suddenly in the fossil record?

Accepted Answer

A) V 
B) W 
C) X 
D) Y 
E) Z 
A) V 
B) W 
C) X 
D) Y 
E) Z

Question 18

What is true of macroevolution?

Accepted Answer

A) It is the same as microevolution, but includes the origin of new species. 
B) It is evolution above the species level. 
C) It is defined as the evolution of microscopic organisms into organisms that can be seen with the naked eye. 
D) It is defined as a change in allele or gene frequency over the course of many generations. 
E) It is the conceptual link between irritability and adaptation. 
A) It is the same as microevolution, but includes the origin of new species. 
B) It is evolution above the species level. 
C) It is defined as the evolution of microscopic organisms into organisms that can be seen with the naked eye. 
D) It is defined as a change in allele or gene frequency over the course of many generations. 
E) It is the conceptual link between irritability and adaptation.

Question 19

What is true of the flightless cormorants of the Galápagos Islands?

Accepted Answer

A) They are descendants of the same common ancestor that gave rise to the unique finches of these islands. 
B) They are close relatives of flightless cormorants from the Americas. 
C) If they are still able to breed successfully with flying cormorants, it would probably be with North American cormorants, rather than with South American cormorants. 
D) Flightless cormorants on one island have restricted gene flow with those on other islands, which could some day lead to a macroevolutionary event. 
E) Their DNA has low levels of sequence homology with the DNA of flying American cormorants. 
A) They are descendants of the same common ancestor that gave rise to the unique finches of these islands. 
B) They are close relatives of flightless cormorants from the Americas. 
C) If they are still able to breed successfully with flying cormorants, it would probably be with North American cormorants, rather than with South American cormorants. 
D) Flightless cormorants on one island have restricted gene flow with those on other islands, which could some day lead to a macroevolutionary event. 
E) Their DNA has low levels of sequence homology with the DNA of flying American cormorants.

Question 20

A narrow hybrid zone separates the toad species Bombina bombina and Bombina variegata. What is true of those alleles that are unique to the parental species?

Accepted Answer

A) Such alleles should be absent. 
B) Their allele frequency should be nearly the same as the allele frequencies in toad populations distant from the hybrid zone. 
C) The alleles' heterozygosity should be higher among the hybrid toads there. 
D) Their allele frequency on one edge of the hybrid zone should roughly equal their frequency on the opposite edge of the hybrid zone. 
A) Such alleles should be absent. 
B) Their allele frequency should be nearly the same as the allele frequencies in toad populations distant from the hybrid zone. 
C) The alleles' heterozygosity should be higher among the hybrid toads there. 
D) Their allele frequency on one edge of the hybrid zone should roughly equal their frequency on the opposite edge of the hybrid zone.

Exam 24: The Origin of Species

The most likely explanation for the recent decline in cichlid species diversity in Lake Victoria is

Suppose that a group of male pied flycatchers migrated from a region where there were no collared flycatchers to a region where both species were present. Assuming events like this are very rare, which of the following scenarios is least likely?

In order for speciation to occur, what must be true?

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

Which of the following statements about speciation is correct?

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification?

Speciation can reveal traits that cause reproductive isolation. These traits

The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of

The next few questions refer to the following evolutionary tree, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change. -Which conclusion can be drawn from this evolutionary tree?

The next few questions refer to the following evolutionary tree, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change. -Which of these five species originated earliest and appeared suddenly in the fossil record?

What is true of macroevolution?

What is true of the flightless cormorants of the Galápagos Islands?

A narrow hybrid zone separates the toad species Bombina bombina and Bombina variegata. What is true of those alleles that are unique to the parental species?

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 Evolution of Populations

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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