Question 1

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)  It always takes millions of years for speciation to occur. 
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)  It always takes millions of years for speciation to occur. 
E)  Speciation is a basis for understanding macroevolution. E

Question 2

Which of these should decline in hybrid zones where reinforcement is occurring?

Accepted Answer

A)  gene flow between distinct gene pools 
B)  speciation 
C)  the genetic distinctness of two gene pools 
D)  mutation rate 
E)  hybrid sterility 
A)  gene flow between distinct gene pools 
B)  speciation 
C)  the genetic distinctness of two gene pools 
D)  mutation rate 
E)  hybrid sterility A

Question 3

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. E

Question 4

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 5

According to the concept of punctuated equilibrium,

Accepted Answer

A)  natural selection is unimportant as a mechanism of evolution. 
B)  given enough time, most existing species will gradually give rise to new species. 
C)  a new species accumulates most of its unique features as it comes into existence. 
D)  evolution of new species features long periods during which changes are occurring, interspersed with short periods of equilibrium, or stasis. 
E)  transitional fossils, intermediate between newer species and their parent species, should be abundant. 
A)  natural selection is unimportant as a mechanism of evolution. 
B)  given enough time, most existing species will gradually give rise to new species. 
C)  a new species accumulates most of its unique features as it comes into existence. 
D)  evolution of new species features long periods during which changes are occurring, interspersed with short periods of equilibrium, or stasis. 
E)  transitional fossils, intermediate between newer species and their parent species, should be abundant.

Question 6

There is still some controversy among biologists about whether Neanderthals should be placed within the same species as modern humans or into a separate species of their own. Most DNA sequence data analyzed so far indicate that there was probably little or no gene flow between Neanderthals and Homo sapiens. Which species concept is most applicable in this example?

Accepted Answer

A)  phylogenetic 
B)  ecological 
C)  morphological 
D)  biological 
A)  phylogenetic 
B)  ecological 
C)  morphological 
D)  biological

Question 7

The next few questions refer to the evolutionary tree in Figure 22.4, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change.
   Figure 22.4
-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 8

The observation that island D. yakuba are more closely related to mainland D. yakuba than island D. yakuba are to D. santomea is best explained by proposing that D. santomea

Accepted Answer

A)  descended from a now-extinct, non-African fruit fly. 
B)  arrived on the island before D. yakuba. 
C)  descended from a single colony of D. yakuba, which had been introduced from elsewhere, with no subsequent colonization events. 
D)  descended from an original colony of D. yakuba, of which there are no surviving members. The current island D. yakuba represent a second colonization event from elsewhere. 
A)  descended from a now-extinct, non-African fruit fly. 
B)  arrived on the island before D. yakuba. 
C)  descended from a single colony of D. yakuba, which had been introduced from elsewhere, with no subsequent colonization events. 
D)  descended from an original colony of D. yakuba, of which there are no surviving members. The current island D. yakuba represent a second colonization event from elsewhere.

Question 9

According to the punctuated equilibria model,

Accepted Answer

A)  natural selection is unimportant as a mechanism of evolution. 
B)  given enough time, most existing species will branch gradually into new species. 
C)  most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species. 
D)  most evolution occurs in sympatric populations. 
E)  speciation is usually due to a single mutation. 
A)  natural selection is unimportant as a mechanism of evolution. 
B)  given enough time, most existing species will branch gradually into new species. 
C)  most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species. 
D)  most evolution occurs in sympatric populations. 
E)  speciation is usually due to a single mutation.

Question 10

The next few questions refer to the following description.
On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences.
-Which type of reproductive isolation operates to keep the mosquitofish isolated, even when fish from different ponds are reunited in the same body of water?

Accepted Answer

A)  behavioral isolation 
B)  habitat isolation 
C)  temporal isolation 
D)  mechanical isolation 
E)  gametic isolation 
A)  behavioral isolation 
B)  habitat isolation 
C)  temporal isolation 
D)  mechanical isolation 
E)  gametic isolation

Question 11

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.

Question 12

The Panama Canal was completed in 1914, and its depth is about 50 feet. After 1914, snapping shrimp species from which habitats should be most likely to form hybrids as the result of the canal?

Accepted Answer

A)  A5 and B5 
B)  A3 and B3 
C)  A1 and B1 
D)  either A1 and A2, or B1 and B2 
E)  A1-A3 and B1-B3 have equal likelihoods of harboring snapping shrimp species that can hybridize. 
A)  A5 and B5 
B)  A3 and B3 
C)  A1 and B1 
D)  either A1 and A2, or B1 and B2 
E)  A1-A3 and B1-B3 have equal likelihoods of harboring snapping shrimp species that can hybridize.

Question 13

The next few questions refer to the evolutionary tree in Figure 22.4, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change.
   Figure 22.4
-Which species is most closely related to species W?

Accepted Answer

A)  V is most closely related to species W. 
B)  X is most closely related to species W. 
C)  Y and Z are equally closely related to W. 
D)  It is not possible to say from this tree. 
A)  V is most closely related to species W. 
B)  X is most closely related to species W. 
C)  Y and Z are equally closely related to W. 
D)  It is not possible to say from this tree.

Question 14

Theoretically, the production of sterile mules by interbreeding between female horses (mares) and male donkeys (jacks) should

Accepted Answer

A)  result in the extinction of one of the two parental species. 
B)  cause convergent evolution. 
C)  strengthen postzygotic barriers between horses and donkeys. 
D)  weaken the intrinsic reproductive barriers between horses and donkeys. 
E)  eventually result in the formation of a single species from the two parental species. 
A)  result in the extinction of one of the two parental species. 
B)  cause convergent evolution. 
C)  strengthen postzygotic barriers between horses and donkeys. 
D)  weaken the intrinsic reproductive barriers between horses and donkeys. 
E)  eventually result in the formation of a single species from the two parental species.

Question 15

Which of the following factors would not contribute to allopatric speciation?

Accepted Answer

A)  A population becomes geographically isolated from the parent population. 
B)  The separated population is small, and genetic drift occurs. 
C)  The isolated population is exposed to different selection pressures than the ancestral population. 
D)  Different mutations begin to distinguish the gene pools of the separated populations. 
E)  Gene flow between the two populations is extensive. 
A)  A population becomes geographically isolated from the parent population. 
B)  The separated population is small, and genetic drift occurs. 
C)  The isolated population is exposed to different selection pressures than the ancestral population. 
D)  Different mutations begin to distinguish the gene pools of the separated populations. 
E)  Gene flow between the two populations is extensive.

Question 16

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 17

The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is

Accepted Answer

A)  sexual selection. 
B)  habitat differentiation. 
C)  polyploidy. 
D)  pollution. 
E)  introduction of a new predator. 
A)  sexual selection. 
B)  habitat differentiation. 
C)  polyploidy. 
D)  pollution. 
E)  introduction of a new predator.

Question 18

The origin of a new plant species by hybridization, coupled with accidents during cell 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 19

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 20

In a hypothetical situation, the National Park Service, which administers Grand Canyon National Park in Arizona, builds a footbridge over the Colorado River at the bottom of the canyon. The footbridge permits migration to occur between populations of two closely related antelope squirrels. Previously, one type of squirrel had been restricted to the terrain south of the river, and the other type had been restricted to terrain on the north side of the river. Immediately before and 10 years after the bridge's completion, researchers collected 10 antelope squirrels from both sides of the river, took blood samples, and collected frequencies of alleles unique to the two types of antelope squirrels (see the graphs in Figures 22.2 and 22.3).
   Figure 22.2
   Figure 22.3
-The data in these graphs indicate that

Accepted Answer

A)  a hybrid zone was established after the completion of the bridge. 
B)  there was no migration between the two squirrel populations after the bridge was completed. 
C)  gene flow occurred from one type of squirrel into the gene pool of the other type of squirrel. 
D)  two-way migration of squirrels occurred across the bridge, but without hybridization. 
E)  some northern squirrels migrated south, but no southern squirrels migrated north across the bridge. 
A)  a hybrid zone was established after the completion of the bridge. 
B)  there was no migration between the two squirrel populations after the bridge was completed. 
C)  gene flow occurred from one type of squirrel into the gene pool of the other type of squirrel. 
D)  two-way migration of squirrels occurred across the bridge, but without hybridization. 
E)  some northern squirrels migrated south, but no southern squirrels migrated north across the bridge.

Exam 22: The Origin of Species

Which of the following statements about speciation is correct?

Which of these should decline in hybrid zones where reinforcement is occurring?

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?

According to the concept of punctuated equilibrium,

The observation that island D. yakuba are more closely related to mainland D. yakuba than island D. yakuba are to D. santomea is best explained by proposing that D. santomea

According to the punctuated equilibria model,

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?

The Panama Canal was completed in 1914, and its depth is about 50 feet. After 1914, snapping shrimp species from which habitats should be most likely to form hybrids as the result of the canal?

The next few questions refer to the evolutionary tree in Figure 22.4, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change. Figure 22.4 -Which species is most closely related to species W?

Theoretically, the production of sterile mules by interbreeding between female horses (mares) and male donkeys (jacks) should

Which of the following factors would not contribute to allopatric speciation?

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?

The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is

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

What is true of macroevolution?

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development, Stem Cells, and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition, Nutrition, and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons, Synapses, and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

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