Deck 26: Speciation

Question 1

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

A)Plant gametes can be produced 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.

Answer 1

A

Question 2

You want to study divergence of populations,and you need to maximize the rate of divergence in order to see results within the period of your grant funding.You will form a new population by taking some individuals from a source population and isolating them so the two populations cannot interbreed.What combination of characteristics would maximize your chance of seeing divergence in this study?
1)Choose a random sample of individuals to form the new population.
2)Choose individuals from one extreme to form the new population.
3)Choose a species to study that produces many offspring.
4)Choose a species to study that produces a few,large offspring.
5)Place the new population in the same type of environment as the source population.
6)Place the new population in a novel environment compared to that of the source population.

A)1,3,and 6
B)1,4,and 6
C)2,3,and 5
D)2,3,and 6
E)2,4,and 6

Answer 2

D

Question 3

Three populations of crickets look very similar,but the males have courtship songs that sound different.What function would this difference in song likely serve if the populations came in contact?

A)a prezygotic isolating mechanism
B)a postzygotic isolating mechanism
C)a behavioral reproductive isolating mechanism
D)a gametic reproductive isolating mechanism
E)two of the above

Answer 3

E

Question 4

The theory of plate tectonics describes movement of plates of the Earth's crust through time.Which of the following can you deduce from what you learned in this chapter about plate tectonics?

A)The continental plates have stopped moving,so continents are now in their final locations.
B)Some other organisms must have speciation patterns similar to those of ratites due to plate tectonics.
C)All distributions of animals on land can be explained by vicariance events due to past plate movements.
D)None of the above statements is true.

Question 5

Most causes of speciation are relatively slow,in that they may take many generations of organism to see changes,except _____.

A)polyploidy
B)vicariance
C)colonization
D)natural selection

Question 6

The two populations are _____.

A)different subspecies,under the morphospecies concept
B)different species,under the biological species concept
C)different species,under the phylogenetic species concept
D)all of the above

Question 7

There is an island in the middle of a large river that houses a large population of ants.Damming of the river causes the island to flood and only the highest points of the island are now above water.The ants cannot swim,so are now in multiple isolated populations.Which of the following best describes this event?

A)isolation by dispersal
B)isolation by vicariance
C)a form of sympatric speciation
D)only a rare development of polyploidy could lead to speciation in this case.
E)speciation will not occur in this case because of gene flow

Question 8

What keeps the two populations separate?

A)temporal reproductive isolation
B)lack of hybrid viability
C)They are already separate species.
D)spatial reproductive isolation
E)behavioral reproductive isolation

Question 9

The peppered moth provides a well-known example of natural selection.The light-colored form of the moth was predominant in England before the industrial revolution.In the mid-nineteenth century,a dark-colored form appeared.The difference is produced by a dominant allele of one gene.By about 1900,approximately 90% of the moths around industrial areas were dark colored,whereas light-colored moths were still abundant elsewhere.Apparently,birds could readily find the light moths against the soot-darkened background in industrial areas and therefore were eating more light moths.Recently,use of cleaner fuels has greatly reduced soot in the landscape,and the dark-colored moths have been disappearing.Should the two forms of moths be considered separate species?

A)Yes,because natural selection has affected the frequency of the two different forms.
B)Yes,because they have completely different coloration.
C)Yes,because they are reproductively isolated based on habitat.
D)Yes,because they have completely different coloration and natural selection has affected the frequency of the two different forms.
E)No.

Question 10

Use the following information when answering the corresponding question(s).
About 3 million years ago,the Isthmus of Panama (a narrow strip of land connecting North and South America)formed,dividing marine organisms into Pacific and Caribbean populations.Researchers have examined species of snapping shrimp on both sides of the isthmus.Based on the morphospecies concept,there appeared 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 were not very interested in courting with each other,and any that did mate almost never 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. )
Refer to the paragraph about the formation of the Isthmus of Panama.The sister populations on opposite sides of the isthmus are true species under which species concept?

A)the morphospecies concept
B)the biological species concept
C)the phylogenetic species concept
D)both the morphospecies and phylogenetic species concepts
E)the morphospecies,biological species,and phylogenetic species concepts

Question 11

Two researchers experimentally formed tetraploid frogs by fertilizing diploid eggs from Rana porosa brevipoda with diploid sperm from Rana nigromaculata.When they mated these tetraploid frogs with each other,most of the offspring that survived to maturity were tetraploid,with chromosome sets of both diploid parent species.Based on these results,if this type of tetraploid formed in the wild,what would be the result? (Y.Kondo and A.Kashiwagi.2004.Experimentally induced autotetraploidy and allotetraploidy in two Japanese pond frogs.Journal of Herpetology 38(3):
381-92. )

A)The two parent species would interbreed and fuse into one species.
B)The two parent species would recognize each other as mates.
C)The tetraploids would be reproductively isolated from both parent species.
D)The tetraploids would be selected against.
E)Any of the above answers could be correct,depending on the environment.

Question 12

How are two different species most likely to evolve from one ancestral species?

A)sympatrically,by a point mutation affecting morphology or behavior
B)sympatrically,due to extensive inbreeding
C)allopatrically,due to extensive inbreeding
D)allopatrically,after the ancestral species has split into two populations
E)phylogenetically,due to heterozygote advantage in hybrids

Question 13

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 meet,what would this situation definitely illustrate?

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

Question 14

Which of the following does not tend to promote speciation?

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

Question 15

Figure 26.1

Refer to Figure 26.1.Which of the following forms a monophyletic group?

A)A,B,C,D
B)C and D
C)D,E,and F
D)E,F,and G
E)all of the above

Question 16

The snake family Typhlopidae consists of small,burrowing species with vestigial eyes.They are found in Australia,sub-Saharan Africa,India and some adjacent areas,and South America.What is the most likely explanation for this distribution?

A)rafting to the different continents from the point of origin on one of these continents
B)convergent evolution in the different regions
C)origin on Gondwana followed by continental drift and some range expansion
D)all of the above

Question 17

Use the following information when answering the corresponding question(s).
About 3 million years ago,the Isthmus of Panama (a narrow strip of land connecting North and South America)formed,dividing marine organisms into Pacific and Caribbean populations.Researchers have examined species of snapping shrimp on both sides of the isthmus.Based on the morphospecies concept,there appeared 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 were not very interested in courting with each other,and any that did mate almost never 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. )
Refer to the paragraph about the formation of the Isthmus of Panama.If the isthmus formed gradually rather than suddenly,what pattern of genetic divergence would you expect to find in these species pairs?

A)similar percentages of difference in DNA sequence between all pairs of sister species
B)greater percentage of difference in DNA sequence between species that inhabit deep water than between species that inhabit shallow water
C)greater percentage of difference in DNA sequence between species that inhabit shallow water than between species that inhabit deep water

Question 18

Which of the following could be a vicariance event for species in that habitat?

A)The level of water in a lake recedes,creating two lakes where there used to be one.
B)Some insects get blown in a storm to a new mountain range,where they lay eggs.
C)Radiation near Chernobyl increases mutation rate,causing an increase in autopolyploidy.
D)All of the above could be vicariance events for species in that habitat.

Question 19

Many songbirds breed in North America in the spring and summer and then migrate to Central and South America in the fall.They spend the winter in these warmer areas,where they feed and prepare for the spring migration north and another breeding season.Two hypothetical species of sparrow,A and B,overwinter together in mixed flocks in Costa Rica.In spring,species A goes to the east coast of North America,and species B goes to the west coast.What can you say about the isolating mechanisms of these two species?

A)They must have strong postzygotic isolating mechanisms in order to spend winter in such close proximity.
B)They must have strong prezygotic isolating mechanisms in order to spend winter in such close proximity.
C)Their winter habitat has no bearing on their degree of reproductive isolation.
D)Reinforcement must be occurring when they winter together.
E)two of the above

Question 20

Use the following information when answering the corresponding question(s).
About 3 million years ago,the Isthmus of Panama (a narrow strip of land connecting North and South America)formed,dividing marine organisms into Pacific and Caribbean populations.Researchers have examined species of snapping shrimp on both sides of the isthmus.Based on the morphospecies concept,there appeared 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 were not very interested in courting with each other,and any that did mate almost never 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. )
Which of the following describes the most likely order of events in speciation?

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,divergence

Question 21

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 of postzygotic isolation is occurring,what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?

A)Calls would be about the same in both areas.
B)Calls would be more similar in areas of sympatry.
C)Calls would be more different in areas of sympatry.
D)There is not enough information to decide what is happening.

Question 22

Two groups of lizards that have long been living in allopatry have recently been reintroduced in the wild.When members of opposite groups mate,the hybrids are almost always inviable.Which of the following could be expected to occur over the long term if the populations remain in sympatry?

A)Hybrid sterility will eventually also develop.
B)Gene flow will reunite the groups into a single species.
C)Hybrids will become prevalent now that the groups are not isolated.
D)Behavioral forms of isolation will develop.
E)There is not enough information to decide which of these will happen.

Question 23

Male frogs give calls that attract female frogs to approach and mate.Researchers examined mating calls of closely related tree frogs in South America.What outcomes can occur where the ranges of two species overlap?

A)The species will interbreed,eventually fusing over time.
B)A stable hybrid zone will form if hybrids are better adapted to the area of overlap than either parent species is.
C)Species will continue to diverge and be isolated by behavioral or genetic mechanisms.
D)All of the above are possible outcomes.
E)None of the above is a possible outcome.

Question 24

If a plant species with 2n = 14 forms an allopolyploid with a plant species with 2n = 18,what would be the likely diploid (2n)number of the allopolyploid?

A)16
B)28
C)32
D)36

Question 25

Which of the following statements about human races is correct?

A)Africans are genetically much closer to Asians than to Caucasians.
B)Humans are one of only a few mammal species with clearly defined genetic races.
C)Very little genetic divergence occurs among different human populations.
D)All of the above are correct.
E)None of the above is correct.

Question 26

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.What effect do these new arrivals have?

A)Their arrival speeds the process of speciation.
B)Their arrival tends to promote adaptation to the new food plants.
C)Their arrival tends to retard adaptation to the new food plants.
D)Their arrival represents a colonizing event.

Question 27

Natural selection for traits that keep distinct populations from reproducing with each other is called reinforcement.When is reinforcement beneficial?

A)when the environment is changing
B)when hybrids have lower fitness than either parent population
C)when prezygotic isolating mechanisms are in place
D)when gene flow is low
E)Reinforcement is beneficial under all of the above conditions.

Question 28

Imagine two North American ground cricket species that contact each other as the southern species moves northward during a period of global warming.These two species do not mate much,due to differences in their courtship songs.The northern cricket does not seem to tolerate the warmer temperatures well but is limited in its ability to move north because it does not normally disperse much.Based on this information,which is the most likely outcome?

A)fusion of the populations
B)reinforcement
C)hybrid zone formation
D)extinction of one of the species
E)creation of a new species

Question 29

A storm brings two formerly separated populations of beetles together.They look very similar.Under the biological species concept,which of the following would show that the two populations are different species?

A)One population breeds in spring,the other in fall.
B)Males of the two populations have slightly different flight patterns in courtship.
C)Males from one population are slightly larger than males from the other population.
D)All of the above are correct.
E)None of the above is correct.

Question 30

A researcher notices that in a certain moth species,some females prefer to feed and lay eggs on domesticated solanaceous plants like potatoes and tomatoes.Other females prefer to feed and lay eggs on wild solanaceous plants like Datura.Both male and female moths primarily use scent to find these plants from afar.Females tend to mate where they feed,and the researcher finds a genetic basis for scent preference in these moths.Based on the above information,what might be occurring in this moth species?

A)divergence in sympatry
B)divergence due to vicariance
C)postzygotic isolation
D)polyploidization
E)There is not enough information to decide what is happening.

Question 31

The common edible frog of Europe is a hybrid between two species,Rana lessonae and Rana ridibunda.The hybrids were first described in 1758 and have a wide distribution,from France across central Europe to Russia.Both male and female hybrids exist,but when they mate among themselves,they are rarely successful in producing offspring.What can you infer from this information?

A)Postzygotic isolation exists between the two frog species.
B)Prezygotic isolation exists between the two frog species.
C)These two species are likely in the process of fusing back into one species.
D)The hybrids form a separate species under the biological species concept.
E)Reinforcement has yet to occur in the hybrid populations.

Question 32

Two species of tree frogs that live sympatrically in the northeastern United States differ in ploidy:
Hyla chrysocelis is diploid,and Hyla versicolor is tetraploid.The frogs are identical in appearance;but their mating calls,which females use to find mates,differ.Which difference most likely evolved first?

A)polyploidy
B)difference in mating calls
C)Polyploidy and different mating calls must have evolved at the same time.

Question 33

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

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 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 harder to form.