Question 1

We can infer a statistically significant difference between two population means when

Accepted Answer

A)  our estimates of the two means are different. 
B)  the variances of the two means do not overlap. 
C)  the standard deviations of the two means do not overlap. 
D)  the 95% confidence intervals for the two means do not overlap. 
E)  the 95% confidence intervals for the two means are of different widths. 
A)  our estimates of the two means are different. 
B)  the variances of the two means do not overlap. 
C)  the standard deviations of the two means do not overlap. 
D)  the 95% confidence intervals for the two means do not overlap. 
E)  the 95% confidence intervals for the two means are of different widths. D

Question 2

Human hunters in the Amazon rain forests kill

Accepted Answer

A)  large numbers of almost every mammal and bird species, for food and for skins. 
B)  large numbers of the smallest mammal and bird species, which are easiest to catch. 
C)  large numbers primarily of the largest mammal and bird species. 
D)  large numbers of mammals and birds, but do not greatly affect population densities. 
E)  only a few mammals and birds, but because humans are keystone species, these few kills greatly reduce population densities. 
A)  large numbers of almost every mammal and bird species, for food and for skins. 
B)  large numbers of the smallest mammal and bird species, which are easiest to catch. 
C)  large numbers primarily of the largest mammal and bird species. 
D)  large numbers of mammals and birds, but do not greatly affect population densities. 
E)  only a few mammals and birds, but because humans are keystone species, these few kills greatly reduce population densities. C

Question 3

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 E

Question 4

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 5

Ecologists summarize feeding interactions among species in a community when they compile a _________.

Accepted Answer

The answer of Ecologists summarize feeding interactions among species in...

Question 6

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 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

Invasive Argentine ants have an important effect on community structure of the South African fynbos because

Accepted Answer

A)  they do not disperse seeds, while native ants do. 
B)  they disperse seeds more effectively than do native ants. 
C)  they disperse seeds in different spatial patterns than do native ants. 
D)  as keystone species, they greatly increase the local diversity of native ants. 
E)  Argentine ants have invaded many communities, but not the South African fynbos. 
A)  they do not disperse seeds, while native ants do. 
B)  they disperse seeds more effectively than do native ants. 
C)  they disperse seeds in different spatial patterns than do native ants. 
D)  as keystone species, they greatly increase the local diversity of native ants. 
E)  Argentine ants have invaded many communities, but not the South African fynbos.

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

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

Accepted Answer

A)  KrillF1F1F1S1F1F1F10DiatomsF1F1F1S1F1F1F10Ross sealF1F1F1S1F1F1F10Crabeater sealF1F1F1S1F1F1F10Killer Whale 
B)  DiatomsF1F1F1S1F1F1F10KrillF1F1F1S1F1F1F10Ross sealF1F1F1S1F1F1F10Crabeater sealF1F1F1S1F1F1F10Killer Whale 
C)  DiatomsF1F1F1S1F1F1F10SquidF1F1F1S1F1F1F10Emperor penguinF1F1F1S1F1F1F10Leopard sealF1F1F1S1F1F1F10Killer whale 
D)  KrillF1F1F1S1F1F1F10SquidF1F1F1S1F1F1F10Weddell sealF1F1F1S1F1F1F10Leopard SealF1F1F1S1F1F1F10Killer whale 
E)  DiatomsF1F1F1S1F1F1F10SquidF1F1F1S1F1F1F10KrillF1F1F1S1F1F1F10Emperor penguinF1F1F1S1F1F1F10Leopard seal 
A)  KrillF1F1F1S1F1F1F10DiatomsF1F1F1S1F1F1F10Ross sealF1F1F1S1F1F1F10Crabeater sealF1F1F1S1F1F1F10Killer Whale 
B)  DiatomsF1F1F1S1F1F1F10KrillF1F1F1S1F1F1F10Ross sealF1F1F1S1F1F1F10Crabeater sealF1F1F1S1F1F1F10Killer Whale 
C)  DiatomsF1F1F1S1F1F1F10SquidF1F1F1S1F1F1F10Emperor penguinF1F1F1S1F1F1F10Leopard sealF1F1F1S1F1F1F10Killer whale 
D)  KrillF1F1F1S1F1F1F10SquidF1F1F1S1F1F1F10Weddell sealF1F1F1S1F1F1F10Leopard SealF1F1F1S1F1F1F10Killer whale 
E)  DiatomsF1F1F1S1F1F1F10SquidF1F1F1S1F1F1F10KrillF1F1F1S1F1F1F10Emperor penguinF1F1F1S1F1F1F10Leopard seal

Question 11

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 12

A keystone species is one

Accepted Answer

A)  that makes up a very large proportion of total community biomass. 
B)  that feeds on a very large fraction of all available prey species. 
C)  that is fed on by a very large fraction of all predators in its community. 
D)  whose feeding activities have a disproportionate effect on the structure of its community. 
E)  that occupies the lowest level (the base) of the food web. 
A)  that makes up a very large proportion of total community biomass. 
B)  that feeds on a very large fraction of all available prey species. 
C)  that is fed on by a very large fraction of all predators in its community. 
D)  whose feeding activities have a disproportionate effect on the structure of its community. 
E)  that occupies the lowest level (the base) of the food web.

Question 13

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 14

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 15

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 16

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 17

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 18

The presence of cleaner wrasse enhances diversity of fishes on coral reefs.

Accepted Answer

A) True 
 B)False

Question 19

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 20

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.

Exam 17: Species Interactions and Community Structure

We can infer a statistically significant difference between two population means when

Human hunters in the Amazon rain forests kill

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?

Keystone species

Ecologists summarize feeding interactions among species in a community when they compile a _________.

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?

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

Invasive Argentine ants have an important effect on community structure of the South African fynbos because

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

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

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

A keystone species is one

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

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

Weaver ants provide effective protection of citrus trees because they

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

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

The presence of cleaner wrasse enhances diversity of fishes on coral reefs.

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

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

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

Socail 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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