Question 1

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 2

The next few questions refer to the following description:
Fossil evidence suggests that polar bears,Ursus maritimus,arose from grizzly bears,Ursus arctos.On average,polar bears are slightly larger than grizzly bears in size and weight.The morphological features/adaptations of polar bears make them well suited to survival in a marine environment.Interbreeding and production of fertile offspring between the two species has been recorded in captivity,and more recently in the wild.
-The biological species concept emphasized the absence of gene flow.Which alternative species concept(s)is(are)applicable to explaining the hybridization between grizzly and polar bears?

Accepted Answer

A) the morphological species concept, since it puts emphasis on similarities between the two species 
B) the ecological species concept, as it addresses organisms' adaptations to changing environmental conditions 
C) the allopatric species concept, since it emphasizes geographical barriers 
D) A, B, and C 
E) all except C 
A) the morphological species concept, since it puts emphasis on similarities between the two species 
B) the ecological species concept, as it addresses organisms' adaptations to changing environmental conditions 
C) the allopatric species concept, since it emphasizes geographical barriers 
D) A, B, and C 
E) all except C

Question 3

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color.The beetles not only pollinate the flowers,but they mate while inside the flowers.A mutant version of the plant with red flowers becomes more common with the passage of time.A particular variant of the beetle prefers the red flowers to the orange flowers.Over time,these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible.What kind of speciation has occurred in this example,and what has driven it?

Accepted Answer

A) allopatric speciation; ecological isolation 
B) sympatric speciation; habitat differentiation 
C) allopatric speciation; behavioural isolation 
D) sympatric speciation; sexual selection 
E) sympatric speciation; allopolyploidy 
A) allopatric speciation; ecological isolation 
B) sympatric speciation; habitat differentiation 
C) allopatric speciation; behavioural isolation 
D) sympatric speciation; sexual selection 
E) sympatric speciation; allopolyploidy

Question 4

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.
-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 5

You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described.Your assignment is to separate them into species.There is no accompanying information as to where or when they were collected.Which species concept will you have to use?

Accepted Answer

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

Question 6

What does the biological species concept use as the primary criterion for determining species boundaries?

Accepted Answer

A) geographic isolation 
B) niche differences 
C) gene flow 
D) morphological similarity 
E) molecular (DNA, RNA, protein)similarity 
A) geographic isolation 
B) niche differences 
C) gene flow 
D) morphological similarity 
E) molecular (DNA, RNA, protein)similarity

Question 7

Polyploidy can be best described as

Accepted Answer

A) a form of speciation that commonly occurs in plants and animals. 
B) an error in mitosis. 
C) a condition that could lead to speciation as a result of duplication of chromosomes. 
D) a condition that requires geographic isolation. 
E) a condition that enhances gene flow. 
A) a form of speciation that commonly occurs in plants and animals. 
B) an error in mitosis. 
C) a condition that could lead to speciation as a result of duplication of chromosomes. 
D) a condition that requires geographic isolation. 
E) a condition that enhances gene flow.

Question 8

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 9

A small number of birds arrive on an island from a neighboring larger island.This small population begins to adapt to the new food plants available on the island,and their beaks begin to change.About twice a year,one or two more birds from the neighboring island arrive.These new arrivals

Accepted Answer

A) speed up the process of speciation. 
B) tend to promote adaptation to the new food plants. 
C) tend to retard adaptation to the new food plants. 
D) represent a colonizing event. 
E) decrease gene flow. 
A) speed up the process of speciation. 
B) tend to promote adaptation to the new food plants. 
C) tend to retard adaptation to the new food plants. 
D) represent a colonizing event. 
E) decrease gene flow.

Question 10

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 11

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 12

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.The oceans were completely separated by the isthmus about 3 million years ago.
-Why should deep-water shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

Accepted Answer

A) They have been geographically isolated from each other for a longer time. 
B) Cold temperatures, associated with deep water, have accelerated the mutation rate, resulting in faster divergence in deep-water shrimp. 
C) The rise of the land bridge was accompanied by much volcanic activity. Volcanic ash contains heavy metals, which are known mutagens. Ash fall caused high levels of heavy metals in the ocean sediments underlying the deep water, resulting in accelerated mutation rates and faster divergence in deep-water shrimp. 
D) Fresh water entering the ocean from the canal is both less dense and cloudier than seawater. The cloudy fresh water interferes with the ability of shallow-water shrimp to locate mating partners, which reduces the frequency of mating, thereby slowing the introduction of genetic variation. 
A) They have been geographically isolated from each other for a longer time. 
B) Cold temperatures, associated with deep water, have accelerated the mutation rate, resulting in faster divergence in deep-water shrimp. 
C) The rise of the land bridge was accompanied by much volcanic activity. Volcanic ash contains heavy metals, which are known mutagens. Ash fall caused high levels of heavy metals in the ocean sediments underlying the deep water, resulting in accelerated mutation rates and faster divergence in deep-water shrimp. 
D) Fresh water entering the ocean from the canal is both less dense and cloudier than seawater. The cloudy fresh water interferes with the ability of shallow-water shrimp to locate mating partners, which reduces the frequency of mating, thereby slowing the introduction of genetic variation.

Question 13

Rank the following from most general to most specific.
1)gametic isolation
2)reproductive isolating mechanism
3)pollen-stigma incompatibility
4)prezygotic isolating mechanism

Accepted Answer

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

Question 14

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 15

Use the following information to answer the question(s)below.
A female fly,full of fertilized eggs,is swept by high winds to an island far out to sea.She is the first fly to arrive on this island and the only fly to arrive in this way.Thousands of years later,her numerous offspring occupy the island,but none of them resembles her.There are,instead,several species,each of which eats only a certain type of food.None of the species can fly and their balancing organs (halteres)are now used in courtship displays.The male members of each species bear modified halteres that are unique in appearance to their species.Females bear vestigial halteres.The ranges of all of the daughter species overlap
-Fly species W,found in a certain part of the island,produces fertile offspring with species Y.Species W does not produce fertile offspring with species X or Z.If no other species can hybridize,then which of the following statements about species W and Y are true?
I.Species W and Y have genomes that are still similar enough for successful meiosis to occur in hybrid flies.
II.Species W and Y have more genetic similarity with each other than either did with the other two species.
III.Species W and Y may fuse into a single species if their hybrids remain fertile over the course of many generations.

Accepted Answer

A) Only I is correct. 
B) Only II is correct. 
C) Only III is correct. 
D) I and II are correct. 
E) I, II, and III are correct. 
A) Only I is correct. 
B) Only II is correct. 
C) Only III is correct. 
D) I and II are correct. 
E) I, II, and III are correct.

Question 16

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.

Exam 24: The Origin of Species

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

You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described.Your assignment is to separate them into species.There is no accompanying information as to where or when they were collected.Which species concept will you have to use?

What does the biological species concept use as the primary criterion for determining species boundaries?

Polyploidy can be best described as

Speciation can reveal traits that cause reproductive isolation.These traits

A small number of birds arrive on an island from a neighboring larger island.This small population begins to adapt to the new food plants available on the island,and their beaks begin to change.About twice a year,one or two more birds from the neighboring island arrive.These new arrivals

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

Rank the following from most general to most specific. 1)gametic isolation 2)reproductive isolating mechanism 3)pollen-stigma incompatibility 4)prezygotic isolating mechanism

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

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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