Question 1

When studying hybridization over time, researchers have found that

Accepted Answer

A) when reinforcement occurs, the production of hybrid individuals continues because hybridization is favoured or reinforced. 
B) when stability occurs, barriers to reproduction are strong, and hybrid numbers decline. 
C) hybridization between polar bears and grizzly bears is one of reinforcement. 
D) when fusion occurs, there is a weakening of reproductive barriers, gene flow continues, and the two hybridizing species become increasingly more alike. 
A) when reinforcement occurs, the production of hybrid individuals continues because hybridization is favoured or reinforced. 
B) when stability occurs, barriers to reproduction are strong, and hybrid numbers decline. 
C) hybridization between polar bears and grizzly bears is one of reinforcement. 
D) when fusion occurs, there is a weakening of reproductive barriers, gene flow continues, and the two hybridizing species become increasingly more alike.

Question 2

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.
-The predatory fish rely on visual cues and speed to capture mosquitofish. Mosquitofish rely on speed and visual cues to avoid the predatory fish. Which adaptation(s)might help the predators survive in ponds that are home to faster mosquitofish? 1. directional selection for increased speed
2. stabilizing selection for speed that matches that of the mosquitofish
3. change in hunting behaviour that replaces reliance on visual cues with reliance on tactile cues, which can be used to hunt at night
4. change in hunting behaviour that eliminates speed in favour of better camouflage, which permits an ambush strategy

Accepted Answer

A) 1 only 
B) 2 only 
C) either 1 or 3 
D) either 2 or 3 
E) 1, 3, or 4 
A) 1 only 
B) 2 only 
C) either 1 or 3 
D) either 2 or 3 
E) 1, 3, or 4

Question 3

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 4

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.
-Speculate on the most likely reason why two different species may be hybridizing more frequently than before.

Accepted Answer

A) There are too few male grizzly bears to mate with females, so females are mating with polar bears. 
B) Female grizzly bears prefer the larger size of male polar bears. 
C) Male polar bears are outcompeting male grizzly bears in coniferous forest habitats. 
D) Grizzly bears are moving farther north to hunt seals and encounter polar bears. 
E) With global warming, polar ice is melting, thus affecting the polar bears' hunting habitat and success; some hungry polar bears may be foraging further in the interior of the tundra and overlapping with foraging grizzly bears. 
A) There are too few male grizzly bears to mate with females, so females are mating with polar bears. 
B) Female grizzly bears prefer the larger size of male polar bears. 
C) Male polar bears are outcompeting male grizzly bears in coniferous forest habitats. 
D) Grizzly bears are moving farther north to hunt seals and encounter polar bears. 
E) With global warming, polar ice is melting, thus affecting the polar bears' hunting habitat and success; some hungry polar bears may be foraging further in the interior of the tundra and overlapping with foraging grizzly bears.

Question 5

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 6

Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?

Accepted Answer

A) the postzygotic barrier called hybrid inviability 
B) the postzygotic barrier called hybrid breakdown 
C) the prezygotic barrier called hybrid sterility 
D) gametic isolation 
A) the postzygotic barrier called hybrid inviability 
B) the postzygotic barrier called hybrid breakdown 
C) the prezygotic barrier called hybrid sterility 
D) gametic isolation

Question 7

What is the best explanation for the speciation event that produced the wild sunflower Helianthus anomalis?

Accepted Answer

A) hybridization of two sunflower species where natural selection produced extensive genetic changes, but with no change in chromosome number 
B) hybridization of two sunflower species where natural selection produced extensive genetic changes with duplication of chromosomes 
C) hybridization followed by asexual reproduction 
D) gradual speciation that occurred over millions of years 
E) allopolyploid speciation 
A) hybridization of two sunflower species where natural selection produced extensive genetic changes, but with no change in chromosome number 
B) hybridization of two sunflower species where natural selection produced extensive genetic changes with duplication of chromosomes 
C) hybridization followed by asexual reproduction 
D) gradual speciation that occurred over millions of years 
E) allopolyploid speciation

Question 8

Prezygotic barriers include all of the following, except for

Accepted Answer

A) habitat isolation. 
B) temporal isolation. 
C) mechanical isolation. 
D) hybrid breakdown. 
E) gametic isolation. 
A) habitat isolation. 
B) temporal isolation. 
C) mechanical isolation. 
D) hybrid breakdown. 
E) gametic isolation.

Question 9

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 10

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 of these habitats is likely to harbour the youngest species?

Accepted Answer

A) A5 
B) B4 
C) A3 
D) B2 
E) A1 
A) A5 
B) B4 
C) A3 
D) B2 
E) A1

Question 11

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 12

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.
  
-The Panama Canal was completed in 1914, and its depth is about 15 metres. 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 harbouring 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 harbouring snapping shrimp species that can hybridize.

Question 13

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.
-If a speciation event occurred on Sao Tomé, producing D. santomea from a parent colony of D. yakuba, then which terms apply? I. macroevolution
II allopatric speciation
III. sympatric speciation

Accepted Answer

A) I only 
B) II only 
C) I and II 
D) I and III 
A) I only 
B) II only 
C) I and II 
D) I and III

Question 14

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 branch gradually into 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 branch gradually into 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 15

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 16

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.
-What is the best way to promote fusion between two related populations of mosquitofish, one of which lives in a predator-rich pond, and the other of which lives in a predator-poor pond?

Accepted Answer

A) Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators. 
B) Transfer only female mosquitofish from a predator-rich pond to a predator-poor pond. 
C) Perform a reciprocal transfer of females between predator-rich and predator-poor ponds. 
D) Remove predators from a predator-rich pond and transfer them to a predator-poor pond. 
A) Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators. 
B) Transfer only female mosquitofish from a predator-rich pond to a predator-poor pond. 
C) Perform a reciprocal transfer of females between predator-rich and predator-poor ponds. 
D) Remove predators from a predator-rich pond and transfer them to a predator-poor pond.

Question 17

The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and

Accepted Answer

A) their chromosomes are no longer homologous enough to permit meiosis. 
B) a constant number of viable, fertile hybrids is produced over the course of generations. 
C) the hybrid zone is inhospitable to hybrid survival. 
D) an increasing number of viable, fertile hybrids is produced over the course of generations. 
E) a decreasing number of viable, fertile hybrids is produced over the course of generations. 
A) their chromosomes are no longer homologous enough to permit meiosis. 
B) a constant number of viable, fertile hybrids is produced over the course of generations. 
C) the hybrid zone is inhospitable to hybrid survival. 
D) an increasing number of viable, fertile hybrids is produced over the course of generations. 
E) a decreasing number of viable, fertile hybrids is produced over the course of generations.

Question 18

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.
  
-In which habitat should one find snapping shrimp most closely related to shrimp that live in habitat A4?

Accepted Answer

A) A3 
B) A5 
C) B4 
D) either A3 or A5 
E) any species from any one of the side A habitats 
A) A3 
B) A5 
C) B4 
D) either A3 or A5 
E) any species from any one of the side A habitats

Question 19

Allopatric speciation is most likely to be observed among which species?

Accepted Answer

A) mice and snails 
B) eagles and gulls 
C) tigers and wolves 
D) pollen of pine trees and grass 
E) bats and butterflies 
A) mice and snails 
B) eagles and gulls 
C) tigers and wolves 
D) pollen of pine trees and grass 
E) bats and butterflies

Question 20

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

Exam 24: The Origin of Species

When studying hybridization over time, researchers have found that

According to the punctuated equilibria model

Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?

What is the best explanation for the speciation event that produced the wild sunflower Helianthus anomalis?

Prezygotic barriers include all of the following, except for

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

According to the concept of punctuated equilibrium

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?

The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and

Allopatric speciation is most likely to be observed among which 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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