Question 1

Reinforcement is most likely to drive the evolution of

Accepted Answer

A)  prezygotic isolating mechanisms,because selection favors alleles that prevent hybridization.
B)  postzygotic isolating mechanisms,because selection acts after the formation of hybrids.
C)  prezygotic isolating mechanisms,because selection favors alleles that promote hybridization.
D)  postzygotic isolating mechanisms,because hybrids have low fitness relative to the parents.E) A) and C)
F) All of the above

Question 2

Two species regularly come into contact and form hybrids that have higher fitness than either of the parental species.What are some likely consequences of regular hybridization between these species? Check all that apply.

Accepted Answer

A)  evolution of a third species
B)  reinforcement of prezygotic isolating mechanisms
C)  extinction of one or both of the parental species.
D)  increased gene flow between the parental species
E)  complete reproductive isolation of the two original speciesF) C) and E)
G) A) and B)

Question 3

How many mass extinctions have been identified during the history of life on Earth?

Accepted Answer

A)  five
B)  six
C)  four
D)  one
E)  noneF) D) and E)
G) A) and B)

Question 4

Which examples would be considered different species under the biological species concept? Check all that apply.

Accepted Answer

A)  Two bear species are able to breed in zoos,but have separate ranges in nature.
B)  Two skunk species look morphologically similar,but are unable to interbreed.
C)  Two snake species look different,but often form fertile hybrids.
D)  Two plant species with no gene flow between them.
E)  Two tree species have different leaf shapes,but form hybrids in their overlapping ranges.F) None of the above
G) A) and B)

Question 5

The process by which related species become more different in order to reduce competition is called ________.

Accepted Answer

character ...

Question 6

Select the reasons why adaptive radiations are often observed on remote volcanic islands.Check all that apply.

Accepted Answer

A)  When a new volcanic island forms,there are many empty niches.
B)  Only a few individuals reach remote islands.
C)  Remote islands have more plant diversity than the mainland does.
D)  Evolution is intrinsically faster on islands than on the mainland.E) A) and B)
F) A) and C)

Question 7

Scientists studying a group of related bird species on an island archipelago discover that these species are always more closely related to each other within an island than they are between any two islands.The most likely explanation for this result is that

Accepted Answer

A)  each bird species evolved different adaptations in allopatry and then colonized the other islands.
B)  one bird species colonized each island and then evolved into distinct species on that island through character displacement.
C)  each bird species became reproductively isolated by living on a different island,then later colonized the other islands and acquired new adaptations.
D)  many ancestral bird species colonized each island.E) B) and C)
F) None of the above

Question 8

Males of many marsupial species have forked penises that are incompatible with the anatomy of female placental mammals.What type of isolating mechanism does this represent?

Accepted Answer

A)  ecological isolation
B)  temporal isolation
C)  mechanical incompatibility
D)  hybrid sterility
E)  prevention of gamete fusionF) None of the above
G) A) and C)

Question 9

Due to character displacement,two closely related species may differ most morphologically when they

Accepted Answer

A)  are allopatric.
B)  are sympatric.
C)  occupy the same niche.
D)  occupy different niches.
E)  share a common ancestor.F) A) and D)
G) C) and E)

Question 10

Very rapid speciation occurred when cichlid fishes were isolated in Lake Victoria.Widespread extinction was dramatically seen when

Accepted Answer

A)  artificial selection stopped.
B)  predatory fish were added.
C)  hybridization stopped.
D)  fishing was prohibited.
E)  insect larvae stocks were depleted.F) None of the above
G) A) and B)

Question 11

Which statements about gradualism and punctuated equilibrium are true? Check all that apply.

Accepted Answer

A)  Darwin's publication On the Origin of Species changed the view of evolution from gradualism to that of punctuated equilibrium.
B)  According to the theory of punctuated equilibrium,evolutionary change occurs only during brief periods of speciation.
C)  Stasis is likely caused by periods of disruptive and directional selection.
D)  Gradualism suggests that evolutionary change is not linked to speciation.E) A) and C)
F) A) and B)

Question 12

Two bird species have different mating calls,occupy different habitats in nature,and when they hybridize,the hybrids are infertile.Which isolating mechanisms maintain these species?

Accepted Answer

A)  ecological isolation,behavioral isolation,and hybrid sterility
B)  mechanical isolation,hybrid sterility,geographical isolation
C)  ecological isolation,mechanical isolation,hybrid sterility
D)  geographical isolation,temporal isolation,behavioral isolationE) A) and C)
F) B) and C)

Question 13

Scientists observed that marine bryozoan fossils lack intermediate forms.This evidence supports which hypotheses? Check all that apply.

Accepted Answer

A)  Evolution occurs in spurts,alternating with long periods of little change.
B)  Evolution proceeds steadily,with gradual,incremental change in a given evolutionary line.
C)  There is variability in the rate of evolution.
D)  Evolution proceeds at a constant rate that is the same for all organisms.E) B) and D)
F) B) and C)

Question 14

When species are kept separate by preventing the formation of hybrid zygotes,the mechanism that keeps the species separate is known as a ________ isolating mechanism.

Accepted Answer

A)  hybridization
B)  postzygotic
C)  prezygotic
D)  adaptive
E)  differentialF) B) and C)
G) A) and B)

Question 15

The type of speciation that results in the formation of separate species as a result of geographic isolation is called ________ speciation.

Accepted Answer

A)  gradual
B)  sympatric
C)  allopatric
D)  sexual
E)  adaptiveF) B) and C)
G) A) and E)

Question 16

The phenomenon where one species diverges into many by occupying a different habitats within a region is called ________.

Accepted Answer

The answer of The phenomenon where one species diverges into...

Question 17

If a new species is produced by the interbreeding of two members of distinct species,this would be ________ speciation achieved via ________.

Accepted Answer

A)  allopatric; autopolyploidy
B)  allopatric; allopolyploidy
C)  sympatric; autopolyploidy
D)  sympatric; allopolyploidy
E)  sympatric; divergenceF) A) and E)
G) D) and E)

Question 18

Several species of sea urchins may inhabit the same tide pool and their reproductive periods overlap.Although they practice external fertilization,they seldom interbreed because eggs produce chemicals that are only attractive to sperm of their own species.This is an example of a ________ barrier that ________.

Accepted Answer

A)  prezygotic; causes geographic isolation
B)  prezygotic; causes temporal isolation
C)  prezygotic; prevents gamete fusion
D)  postzygotic; prevents zygote fusion
E)  postzygotic; causes hybrid infertilityF) C) and D)
G) D) and E)

Question 19

Several new tetraploid species of a plant called salsify (Tragopogon) known as salsify have arisen in western North America.These new species each arose from a diploid species that went through the process of allopolyploidy.This mode of speciation is a type of ________ and it occurs ________.

Accepted Answer

A)  allopatric speciation; almost instantaneously
B)  allopatric speciation; very slowly
C)  sympatric speciation; almost instantaneously
D)  sympatric speciation; very slowly
E)  adaptive radiation; very slowlyF) A) and B)
G) A) and C)

Question 20

Which statement is true about speciation on island archipelagos?

Accepted Answer

A)  Speciation is slow because it depends on emigration from the mainland.
B)  Most speciation occurs allopatrically.
C)  Ecological competition may cause new species to go extinct slowing speciation.
D)  Speciation by polyploidy is most common.
E)  Species clusters are less common.F) B) and D)
G) B) and E)

Exam 22: The Origin of Species

Select the reasons why adaptive radiations are often observed on remote volcanic islands.Check all that apply.

Correct AnswerverifiedShow Answer

The phenomenon where one species diverges into many by occupying a different habitats within a region is called ________.

Correct AnswerverifiedShow Answer

Males of many marsupial species have forked penises that are incompatible with the anatomy of female placental mammals.What type of isolating mechanism does this represent?

Correct AnswerverifiedShow Answer

How many mass extinctions have been identified during the history of life on Earth?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which statement is true about speciation on island archipelagos?

Correct AnswerverifiedShow Answer

Two species regularly come into contact and form hybrids that have higher fitness than either of the parental species.What are some likely consequences of regular hybridization between these species? Check all that apply.

Correct AnswerverifiedShow Answer

If a new species is produced by the interbreeding of two members of distinct species,this would be ________ speciation achieved via ________.

Correct AnswerverifiedShow Answer

The type of speciation that results in the formation of separate species as a result of geographic isolation is called ________ speciation.

Correct AnswerverifiedShow Answer

Several new tetraploid species of a plant called salsify (Tragopogon) known as salsify have arisen in western North America.These new species each arose from a diploid species that went through the process of allopolyploidy.This mode of speciation is a type of ________ and it occurs ________.

Correct AnswerverifiedShow Answer

Due to character displacement,two closely related species may differ most morphologically when they

Correct AnswerverifiedShow Answer

Reinforcement is most likely to drive the evolution of

Correct AnswerverifiedShow Answer

Which statements about gradualism and punctuated equilibrium are true? Check all that apply.

Correct AnswerverifiedShow Answer

When species are kept separate by preventing the formation of hybrid zygotes,the mechanism that keeps the species separate is known as a ________ isolating mechanism.

Correct AnswerverifiedShow Answer

Scientists studying a group of related bird species on an island archipelago discover that these species are always more closely related to each other within an island than they are between any two islands.The most likely explanation for this result is that

Correct AnswerverifiedShow Answer

The process by which related species become more different in order to reduce competition is called ________.

Correct Answerverifiedcharacter ...View AnswerShow Answer

Two bird species have different mating calls,occupy different habitats in nature,and when they hybridize,the hybrids are infertile.Which isolating mechanisms maintain these species?

Correct AnswerverifiedShow Answer

Scientists observed that marine bryozoan fossils lack intermediate forms.This evidence supports which hypotheses? Check all that apply.

Correct AnswerverifiedShow Answer

Very rapid speciation occurred when cichlid fishes were isolated in Lake Victoria.Widespread extinction was dramatically seen when

Correct AnswerverifiedShow Answer

Which examples would be considered different species under the biological species concept? Check all that apply.

Correct AnswerverifiedShow Answer

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If a new species is produced by the interbreeding of two members of distinct species,this would be speciation achieved via .

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Several new tetraploid species of a plant called salsify (Tragopogon) known as salsify have arisen in western North America.These new species each arose from a diploid species that went through the process of allopolyploidy.This mode of speciation is a type of and it occurs .

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character ...
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