Question 1

Which is the correct order of prey consumption in the Antarctic pelagic food web?

Accepted Answer

A)  Krill→Diatoms→Ross seal→Crabeater seal→Killer Whale 
B)  Diatoms→Krill→Ross seal→Crabeater seal→Killer Whale 
C)  Diatoms→Squid→Emperor penguin→Leopard seal→Killer whale 
D)  Krill→Squid→Weddell seal→Leopard Seal→Killer whale 
E)  Diatoms→Squid→Krill→Emperor penguin→Leopard seal 
A)  Krill→Diatoms→Ross seal→Crabeater seal→Killer Whale 
B)  Diatoms→Krill→Ross seal→Crabeater seal→Killer Whale 
C)  Diatoms→Squid→Emperor penguin→Leopard seal→Killer whale 
D)  Krill→Squid→Weddell seal→Leopard Seal→Killer whale 
E)  Diatoms→Squid→Krill→Emperor penguin→Leopard seal D

Question 2

Which research methods were used by both Redouan Bshary and Caroline Christian in their studies of mutualistic keystone species? (Select all that apply.)

Accepted Answer

A)  Experimental removal and addition of organisms 
B)  Natural removal and addition of organisms 
C)  Counting and identification of organisms 
D)  Comparison of different spatial areas 
E)  Median change in species richness 
A)  Experimental removal and addition of organisms 
B)  Natural removal and addition of organisms 
C)  Counting and identification of organisms 
D)  Comparison of different spatial areas 
E)  Median change in species richness C, D

Question 3

Which statement best sums up the relationship between density of the herbivorous snail Littorina and the diversity of algae in its habitat?

Accepted Answer

A)  Highest diversity when Littorina are abundant, in all habitats 
B)  Highest diversity when Littorina are rare, in all habitats 
C)  Highest diversity when Littorina densities are intermediate, in all habitats 
D)  Highest diversity in tidepools when Littorina are rare, but in emergent habitats when Littorina densities are intermediate 
E)  Highest diversity in tidepools when Littorina densities are intermediate, but in tidepools when Littorina are rare 
A)  Highest diversity when Littorina are abundant, in all habitats 
B)  Highest diversity when Littorina are rare, in all habitats 
C)  Highest diversity when Littorina densities are intermediate, in all habitats 
D)  Highest diversity in tidepools when Littorina are rare, but in emergent habitats when Littorina densities are intermediate 
E)  Highest diversity in tidepools when Littorina densities are intermediate, but in tidepools when Littorina are rare E

Question 4

In zooplankton and intertidal communities, as the overall diversity of the food web increases, the proportion of predators in the web

Accepted Answer

A)  tends to decrease. 
B)  tends to increase. 
C)  first decreases, then increases again. 
D)  first increases, then decreases again. 
E)  stays about the same. 
A)  tends to decrease. 
B)  tends to increase. 
C)  first decreases, then increases again. 
D)  first increases, then decreases again. 
E)  stays about the same.

Question 5

Kirk Winemiller, who described the feeding relations among freshwater fish in Venezuela and Costa Rica, simplified the food webs from his study sites by presenting common-fish webs. Common-fish webs

Accepted Answer

A)  exclude rare species. 
B)  both exclude rare species and include the fish species whose aggregate abundance comprise 95% of the individuals collected. 
C)  exclude species that do not comprise at least 30% of the community. 
D)  include the fish species whose aggregate abundance comprise 95% of the individuals collected. 
E)  exclude species that do not comprise at least 40% of the community. 
A)  exclude rare species. 
B)  both exclude rare species and include the fish species whose aggregate abundance comprise 95% of the individuals collected. 
C)  exclude species that do not comprise at least 30% of the community. 
D)  include the fish species whose aggregate abundance comprise 95% of the individuals collected. 
E)  exclude species that do not comprise at least 40% of the community.

Question 6

It had been thought that Brassica nigra competitively displaced the native grass Nassella pulchra, but Orrock et al. showed that it was likely apparent competition when

Accepted Answer

A)  B. nigra shaded out N. pulchra. 
B)  N. pulchra did not germinate near B. nigra. 
C)  B. nigra sheltered mammal herbivores which consumed N. pulchra. 
D)  B. nigra had higher survival after fire than N. pulchra. 
E)  All of the choices are correct. 
A)  B. nigra shaded out N. pulchra. 
B)  N. pulchra did not germinate near B. nigra. 
C)  B. nigra sheltered mammal herbivores which consumed N. pulchra. 
D)  B. nigra had higher survival after fire than N. pulchra. 
E)  All of the choices are correct.

Question 7

In the Washington intertidal community studied by Robert Paine, the most important limiting resource is

Accepted Answer

A)  space. 
B)  light. 
C)  plankton. 
D)  nitrogen. 
E)  water. 
A)  space. 
B)  light. 
C)  plankton. 
D)  nitrogen. 
E)  water.

Question 8

The impact of Argentine ants on species diversity in the South African fynbos is most dramatic following fires.

Accepted Answer

A) True 
 B)False

Question 9

Martinsen, Driebe, and Whitham provided evidence for ________ with beaver consumption of cottonwoods resulting in higher densities of herbivorous beetles.

Accepted Answer

A)  indirect keystone predation 
B)  indirect commensalism 
C)  apparent competition 
D)  keystone predation 
E)  indirect competition 
A)  indirect keystone predation 
B)  indirect commensalism 
C)  apparent competition 
D)  keystone predation 
E)  indirect competition

Question 10

Based on studies by Jane Lubchenco, what influence does the population density of the herbivorous intertidal snail, Littorina littorea, have on the number of algal species?

Accepted Answer

A)  As snail density increases from low to medium, the number of algal species increases. 
B)  As snail density increases from medium to high, the number of algal species increases. 
C)  As snail density increases from low to medium, the number of algal species decreases. 
D)  As snail density increases from medium to high, the number of algal species decreases. 
E)  Both as snail density increases from low to medium, the number of algal species increases and as snail density increases from medium to high, the number of algal species decreases. 
A)  As snail density increases from low to medium, the number of algal species increases. 
B)  As snail density increases from medium to high, the number of algal species increases. 
C)  As snail density increases from low to medium, the number of algal species decreases. 
D)  As snail density increases from medium to high, the number of algal species decreases. 
E)  Both as snail density increases from low to medium, the number of algal species increases and as snail density increases from medium to high, the number of algal species decreases.

Question 11

Weaver ants provide effective protection of citrus trees because they

Accepted Answer

A)  remove harmful soft-scale insects (mealybugs). 
B)  remove all plant-feeding insects. 
C)  cultivate soft-scale insects, but do not allow them to feed on the trees. 
D)  cultivate soft-scale insects, but still allow them to be attacked by parasitoids and predators. 
E)  None of the choices are correct. 
A)  remove harmful soft-scale insects (mealybugs). 
B)  remove all plant-feeding insects. 
C)  cultivate soft-scale insects, but do not allow them to feed on the trees. 
D)  cultivate soft-scale insects, but still allow them to be attacked by parasitoids and predators. 
E)  None of the choices are correct.

Question 12

Removal of Pisaster starfish in the Washington intertidal leads to a decline in diversity of other invertebrate species.

Accepted Answer

A) True 
 B)False

Question 13

Keystone species

Accepted Answer

A)  appear to be common in terrestrial systems, but not in aquatic ones. 
B)  appear to be common in both terrestrial and aquatic systems. 
C)  appear to be common in aquatic systems, but not in terrestrial ones. 
D)  by definition, cannot occur in aquatic systems. 
E)  by definition, cannot occur in terrestrial systems. 
A)  appear to be common in terrestrial systems, but not in aquatic ones. 
B)  appear to be common in both terrestrial and aquatic systems. 
C)  appear to be common in aquatic systems, but not in terrestrial ones. 
D)  by definition, cannot occur in aquatic systems. 
E)  by definition, cannot occur in terrestrial systems.

Question 14

In Jane Lubchenco's tidepool system, removal of the herbivorous snail Littorina led to

Accepted Answer

A)  dominance of the tidepools by the unpalatable alga Chondrus. 
B)  replacement of Chondrus by the more palatable alga Enteromorpha. 
C)  replacement of Chondrus by other algae better adapted to herbivory. 
D)  replacement of Enteromorpha by other algae that are better competitors. 
E)  no marked change in the algal community. 
A)  dominance of the tidepools by the unpalatable alga Chondrus. 
B)  replacement of Chondrus by the more palatable alga Enteromorpha. 
C)  replacement of Chondrus by other algae better adapted to herbivory. 
D)  replacement of Enteromorpha by other algae that are better competitors. 
E)  no marked change in the algal community.

Question 15

Teja Tscharntke simplified the food web associated with the wetland reed Phragmites australis by dividing the species into which of the following major trophic levels?

Accepted Answer

A)  Plant, herbivore, piscivore, granivore 
B)  Herbivore, carnivore, detritivore, consumer 
C)  Herbivore, parasite, carnivore, detritivore 
D)  Plant, herbivore, parasite, carnivore 
E)  Plant, detritivore, parasite, herbivore 
A)  Plant, herbivore, piscivore, granivore 
B)  Herbivore, carnivore, detritivore, consumer 
C)  Herbivore, parasite, carnivore, detritivore 
D)  Plant, herbivore, parasite, carnivore 
E)  Plant, detritivore, parasite, herbivore

Question 16

Cleaner wrasse are mutualists of other coral reef fishes. What benefit do they provide to those other fish?

Accepted Answer

A)  They suppress diseases because they consume carcasses of dead fish. 
B)  They keep water oxygenated because they consume organic debris before it can rot. 
C)  They keep fish relatively free of externally feeding parasites. 
D)  They maintain fish habitat by keeping corals free of encrusting algae. 
E)  They reduce fish mortality by repelling large vertebrate predators. 
A)  They suppress diseases because they consume carcasses of dead fish. 
B)  They keep water oxygenated because they consume organic debris before it can rot. 
C)  They keep fish relatively free of externally feeding parasites. 
D)  They maintain fish habitat by keeping corals free of encrusting algae. 
E)  They reduce fish mortality by repelling large vertebrate predators.

Question 17

In a mangrove forest in Central America, mangrove trees were found to contain between 60-85% of the total above-ground biomass. How would you categorize mangrove trees in this ecosystem?

Accepted Answer

A)  A foundation species 
B)  A keystone species 
C)  Both a foundation and a keystone species 
D)  Neither a foundation nor a keystone species 
A)  A foundation species 
B)  A keystone species 
C)  Both a foundation and a keystone species 
D)  Neither a foundation nor a keystone species

Question 18

Teja Tscharntke's studies of the food web associated with Phragmites reeds revealed that

Accepted Answer

A)  only a single parasitoid species can persist exploiting a single species of herbivore. 
B)  only a single herbivore species can persist attacking a single species of plant. 
C)  predation by birds actually protects herbivores, because the birds feed on parasitoid-infested herbivore galls but not uninfested galls. 
D)  within local food webs, all interactions tend to be of roughly the same strength. 
E)  recognizing variation in interaction strength can greatly simplify the depiction of a food web. 
A)  only a single parasitoid species can persist exploiting a single species of herbivore. 
B)  only a single herbivore species can persist attacking a single species of plant. 
C)  predation by birds actually protects herbivores, because the birds feed on parasitoid-infested herbivore galls but not uninfested galls. 
D)  within local food webs, all interactions tend to be of roughly the same strength. 
E)  recognizing variation in interaction strength can greatly simplify the depiction of a food web.

Question 19

The use of predaceous weaver ants to control pest insects in citrus orchards was first recorded in

Accepted Answer

A)  California in the 1950s. 
B)  Florida in the 1920s. 
C)  Mexico in Mayan times. 
D)  China in the 17th century. 
E)  China in the 4th century. 
A)  California in the 1950s. 
B)  Florida in the 1920s. 
C)  Mexico in Mayan times. 
D)  China in the 17th century. 
E)  China in the 4th century.

Question 20

If Brassica nigra and Nassella pulchra were in direct competition, the density of N. pulchra would increase with distance from B. nigra patches, regardless of the abundance of herbivores.

Accepted Answer

A) True 
 B)False

Exam 17: Species Interactions and Community Structure

Which is the correct order of prey consumption in the Antarctic pelagic food web?

Which research methods were used by both Redouan Bshary and Caroline Christian in their studies of mutualistic keystone species? (Select all that apply.)

Which statement best sums up the relationship between density of the herbivorous snail Littorina and the diversity of algae in its habitat?

In zooplankton and intertidal communities, as the overall diversity of the food web increases, the proportion of predators in the web

Kirk Winemiller, who described the feeding relations among freshwater fish in Venezuela and Costa Rica, simplified the food webs from his study sites by presenting common-fish webs. Common-fish webs

It had been thought that Brassica nigra competitively displaced the native grass Nassella pulchra, but Orrock et al. showed that it was likely apparent competition when

In the Washington intertidal community studied by Robert Paine, the most important limiting resource is

The impact of Argentine ants on species diversity in the South African fynbos is most dramatic following fires.

Martinsen, Driebe, and Whitham provided evidence for ________ with beaver consumption of cottonwoods resulting in higher densities of herbivorous beetles.

Based on studies by Jane Lubchenco, what influence does the population density of the herbivorous intertidal snail, Littorina littorea, have on the number of algal species?

Weaver ants provide effective protection of citrus trees because they

Removal of Pisaster starfish in the Washington intertidal leads to a decline in diversity of other invertebrate species.

Keystone species

In Jane Lubchenco's tidepool system, removal of the herbivorous snail Littorina led to

Teja Tscharntke simplified the food web associated with the wetland reed Phragmites australis by dividing the species into which of the following major trophic levels?

Cleaner wrasse are mutualists of other coral reef fishes. What benefit do they provide to those other fish?

In a mangrove forest in Central America, mangrove trees were found to contain between 60-85% of the total above-ground biomass. How would you categorize mangrove trees in this ecosystem?

Teja Tscharntke's studies of the food web associated with Phragmites reeds revealed that

The use of predaceous weaver ants to control pest insects in citrus orchards was first recorded in

If Brassica nigra and Nassella pulchra were in direct competition, the density of N. pulchra would increase with distance from B. nigra patches, regardless of the abundance of herbivores.

Introduction to Ecology: Historical Foundations and Developing Frontiers

Life on Land

Life in Water

Population Genetics and Natural Selection

Temperature Relations

Water Relations

Energy and Nutrient Relations

Social Relations

Population Distribution and Abundance

Population Dynamics

Population Growth

Life Histories

Competition

Exploitative Interactions: Predation, Herbivory, Parasitism, and Disease

Mutualism

Species Abundance and Diversity

Primary Production and Energy Flow

Nutrient Cycling and Retention

Succession and Stability

Landscape Ecology

Geographic Ecology

Global Ecology

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