Question 1

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 is/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, II, and III are correct.E) B) and C)
F) A) and D)

Question 2

Use the following description to answer the question(s)  below.
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 two of the following have operated to increase divergence between mosquitofish populations on Andros?
1)  improved gene flow
2)  bottleneck effect
3)  sexual selection
4)  founder effect
5)  natural selection

Accepted Answer

A)   1 and 3
B)   2 and 3
C)   2 and 4
D)   3 and 4
E)   3 and 5F) B) and D)
G) B) and C)

Question 3

Which of the following does NOT tend to promote speciation?

Accepted Answer

A)   the founder effect
B)   gene flow
C)   natural selection
D)   polyploidy
E)   disruptive selectionF) B) and D)
G) A) and D)

Question 4

Why is speciation by polyploidy more likely in plants than in animals?

Accepted Answer

A)   Plant gametes can be produced by meiosis from somatic cells that have undergone many rounds of mitosis.
B)   Plant gametes lack postzygotic isolating mechanisms.
C)   Plants are sessile and, therefore, are never prezygotically isolated to ensure reproduction.
D)   Plants are sessile and cannot speciate via dispersal.
E)   Plants lack the DNA repair enzymes that animals have.F) None of the above
G) B) and C)

Question 5

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 as selection favors those birds with larger beaks. 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 eventE) B) and D)
F) B) and C)

Question 6

House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of ________.

Accepted Answer

A)   prezygotic isolation
B)   reinforcement
C)   autopolyploidy
D)   allopatric speciation
E)   sympatric speciationF) A) and B)
G) B) and E)

Question 7

Which of the following statements explains why animals are less likely than plants to speciate by polyploidy?

Accepted Answer

A)   Animals self-fertilize less often than plants, so diploid gametes are less likely to fuse.
B)   Animals have better mechanisms for repairing chromosomes than plants have.
C)   Animals are more mobile, so they have more effective prezygotic isolating mechanisms.
D)   Animals are more mobile, so populations get separated far less often.
E)   Animals use a more rigorous form of meiosis than plants, making diploid gametes much more difficult to form.F) A) and D)
G) D) and E)

Question 8

A hybrid zone is properly defined as ________.

Accepted Answer

A)   an area where the ranges of two closely related species overlap, but do not interbreed
B)   an area where mating occurs between members of two closely related species, producing viable offspring
C)   a zone where sterile hybrids form, kept separate by postzygotic barriers
D)   an area where members of two closely related species intermingle, but gene flow is prevented by prezygotic barriersE) B) and C)
F) B) and D)

Question 9

The origin of a new plant species by hybridizing two existing species, coupled with accidents during cell division, is an example of ________.

Accepted Answer

A)   allopatric speciation and autopolyploidy
B)   sympatric speciation and allopolyploidy
C)   allopatric speciation and allopolyploidy
D)   sympatric speciation and autopolyploidyE) B) and D)
F) A) and B)

Question 10

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)   an increasing number of infertile hybrids is produced over the course of the next 100 generations
C)   no reproduction occurs in the hybrid zone
D)   an increasing number of viable, fertile hybrids is produced over the course of the next 100 generations
E)   a decreasing number of viable, fertile hybrids is produced over the course of the next 100 generationsF) A) and B)
G) None of the above

Question 11

Use the following description to answer the question(s)  below.
The Isthmus of Panama (a narrow strip of land connecting North and South America)  started rising about 10 million years ago. The Pacific and Caribbean oceans were completely separated by the isthmus about 3 million years ago.
Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appear to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus, were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs seldom courted each other, and those that did mate seldom produced fertile offspring. (N. Knowlton, L. A. Weigt, L. A. Solorzano, D. K. Mills, and E. Bermingham. 1993. Divergence in proteins, mitochondrial DNA, and reproductive incompatibility across the Isthmus of Panama. Science 260:1629-32.) 
-There are currently two large, permanent bridges that span the Panama Canal. The bridges are about eight miles apart. If snapping shrimp avoid swimming at night and avoid swimming under shadows, then what do these bridges represent for the snapping shrimp?

Accepted Answer

A)   sources of refuge
B)   geographic barriers
C)   sources of a hybrid zone between the two bridges
D)   sources for increased gene flowE) B) and C)
F) A) and C)

Question 12

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?

Accepted Answer

A)   Calls would be equally similar in both areas.
B)   Calls would be more similar in areas of sympatry.
C)   Calls would be more different in areas of sympatry.
D)   None of the above outcomes would be expected.E) None of the above
F) B) and C)

Question 13

Which process led to the formation of the species pairs of Pacific and Caribbean snapping shrimp?

Accepted Answer

A)   allopatric speciation by vicariance
B)   allopatric speciation by dispersal
C)   sympatric speciation by vicariance
D)   sympatric speciation by dispersalE) A) and B)
F) None of the above

Question 14

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 habitatsF) B) and E)
G) B) and C)

Question 15

Which of the following describes the most likely order of events in allopatric speciation?

Accepted Answer

A)   genetic drift, genetic isolation, divergence
B)   genetic isolation, divergence, genetic drift
C)   divergence, genetic drift, genetic isolation
D)   divergence, genetic isolation, genetic drift
E)   genetic isolation, genetic drift, divergenceF) C) and E)
G) B) and C)

Question 16

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.F) A) and D)
G) A) and E)

Exam 24: Speciation

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?

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

Correct Answer
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Which of the following does NOT tend to promote speciation?

Correct Answer
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The origin of a new plant species by hybridizing two existing species, coupled with accidents during cell division, is an example of ________.

Correct Answer
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Correct Answer
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A hybrid zone is properly defined as ________.

Correct Answer
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Which of the following statements explains why animals are less likely than plants to speciate by polyploidy?

Correct Answer
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Which process led to the formation of the species pairs of Pacific and Caribbean snapping shrimp?

Correct Answer
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Correct Answer
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Correct Answer
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Why is speciation by polyploidy more likely in plants than in animals?

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

Correct Answer
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Correct Answer
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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?

Correct Answer
verified

Which of the following describes the most likely order of events in allopatric speciation?

Correct Answer
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Correct Answer
verified

Exam 24: Speciation

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following does NOT tend to promote speciation?

Correct AnswerverifiedShow Answer

The origin of a new plant species by hybridizing two existing species, coupled with accidents during cell division, is an example of ________.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A hybrid zone is properly defined as ________.

Correct AnswerverifiedShow Answer

Which of the following statements explains why animals are less likely than plants to speciate by polyploidy?

Correct AnswerverifiedShow Answer

Which process led to the formation of the species pairs of Pacific and Caribbean snapping shrimp?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Why is speciation by polyploidy more likely in plants than in animals?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Which of the following describes the most likely order of events in allopatric speciation?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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