Deck 43: Ecological and Evolutionary Consequences of Interactions Within and Among Species

Question 1

The relationship between Merriam's kangaroo rats and large-seeded native bunchgrasses in southern Arizona demonstrates that

A) consumer-resource interactions usually lead to an arms race.
B) rarity advantage promotes species coexistence.
C) intraspecific competition can increase carrying capacity.
D) commensalism does not involve a limiting resource.
E) changes in environmental conditions may alter the nature of interspecific relationships.

Answer 1

E

Question 2

Tree sloths feed on leaves and buds,which are digested by bacteria that inhabit the sloth's large stomach.While in a tree,the sloth is difficult for predators to find because it is tinted green from the cyanobacteria that live in its fur.A variety of nonbiting insects also live in the fur,but they appear to have no effect on the sloth.Based on this information,one can say that the sloth has mutualistic interactions with the _______ and the _______.

A) leaves and buds;digestive bacteria
B) digestive bacteria;cyanobacteria
C) cyanobacteria;insects
D) leaves and buds;insects
E) leaves and buds;cyanobacteria

Answer 2

B

Question 3

The relationship between a zebra and the lion that eats it is an example of what kind of interaction?

A) Competition
B) Mutualism
C) Amensalism
D) Commensalism
E) Consumer-resource

Answer 3

E

Question 4

The fecal matter from giraffes helps fertilize a particular species of plant,thus increasing the plant's ability to grow in a particular area.The plant has no effect on giraffes.The relationship between the giraffes and the plants is best described as

A) mutualism.
B) amensalism.
C) herbivory.
D) consumer-resource.
E) commensalism.

Question 5

Although most herbivory involves an antagonistic interaction (i.e. ,one species benefits,the other is harmed),some herbivorous interactions do not.Which example is least likely to be an antagonistic interaction?

A) Aphids pierce stems and consume plant sap,but they do not damage other plant parts.
B) Nematodes feed on the starches in plant roots;the roots live but their growth is slowed.
C) Bears eat blueberries;then they defecate the blueberry seeds throughout the forest,and the seeds germinate.
D) Gypsy moth caterpillars feed on the leaves of oak and aspen,defoliating and stressing the trees.
E) Leaf miner insects feed on sugars in leaf cells without killing the leaves.

Question 6

A moth and a beetle both lay eggs on the same species of plant and the larvae of both develop on the plant.Removal experiments show that the moth and the beetle each perform less well on the plant when the other species is removed.The relationship between the moth and the beetle is best described as

A) mutualism.
B) amensalism.
C) herbivory.
D) consumer-resource.
E) commensalism.

Question 7

A cow's rumen,or first stomach,provides the ideal environment for a variety of microbes.When a cow consumes grass,these microbes digest the grass,releasing nutrients both for their own and for the cow's use.While most of the microbes continue to live in the rumen,some of them are killed during the digestive process and provide additional nutrition for the cow.This complex relationship between the cow and her microbes has features of which two categories of interactions?

A) Mutualism and predation
B) Competition and mutualism
C) Commensalism and amensalism
D) Predation and parasitism
E) Amensalism and competition

Question 8

In what way does amensalism differ from commensalism?

A) In amensalism,only one species is affected by the other;in commensalism,both species affect each other.
B) In commensalism,only one species is affected by the other;in amensalism,both species affect each other.
C) In amensalism,the species that is affected by the other is negatively affected.In commensalism,the species that is affected by the other is positively affected.
D) In commensalism,the species that is affected by the other is negatively affected.In amensalism,the species that is affected by the other is positively affected.
E) British ecologists use the word "amensalism" and American ecologists use the word "commensalism" to describe the same phenomenon.

Question 9

Which relationship does not involve negative effects for at least one of the species in the interaction?

A) Competition
B) Predation
C) Herbivory
D) Commensalism
E) Amensalism

Question 10

A bacterium that infects a fly causes it harm and is completely dependent on the fly for survival and reproduction.Over time,however,adaptations by both the fly and the bacterium decrease the negative effects of the bacterium on the fly.We can thus say that the relationship has evolved from parasitism toward

A) commensalism.
B) amensalism.
C) mutualism.
D) a consumer-resource interaction.
E) herbivory.

Question 11

Which example is a mutualistic interaction?

A) Barnacles obtain safe haven by riding on a whale,while the whale is unaffected.
B) A bacterial species lives inside a plant's roots and provides usable nitrogen to the plant,which in turn provides sugar nutrients to the bacteria.
C) A virus infects a bird,thus reducing the bird's fecundity.
D) A wasp lays its egg inside a caterpillar,and the hatched wasp larva consumes the caterpillar.
E) A bluejay forces sparrows to leave a bird feeder so that it can eat the seeds.

Question 12

Two species of plants that are competitors in nature are grown together in the greenhouse.When they are fed additional nitrogen,species A thrives at the expense of species B.When they are fed additional phosphorus,species B thrives at the expense of species A.Increasing the concentration of carbon dioxide has no effect on either species.Both species show improved growth when they are given additional sunlight,but additional moisture has little effect on either one.Based on this information,which resource is most likely to be limiting for both species?

A) Moisture
B) Nitrogen
C) Phosphorus
D) Sunlight
E) Carbon dioxide

Question 13

Amensalism does not show the same types of ecological and evolutionary dynamics as competition,consumer‒resource interactions,and mutualism.The reason is that amensalism

A) has only negative effects,whereas all of the other interactions have only positive effects.
B) has only positive effects,whereas all of the other interactions have only negative effects.
C) affects only one species,whereas the other relationships affect at least two species.
D) involves a limiting resource,while the others do not.
E) does not involve a limiting resource,whereas all the other relationships do.

Question 14

Leaf-cutter ants originated in

A) North America.
B) South America.
C) Asia.
D) Africa.
E) Europe.

Question 15

While pursuing prey,a bear smashes into and destroys a bush,and then continues pursuing its prey.The relationship between the bear and the bush would be described as

A) herbivory.
B) consumer-resource.
C) amensalism.
D) commensalism.
E) predation.

Question 16

Leaf-cutter ants that tend fungal gardens protect their crop from mold by means of

A) interactions with a bacterium.
B) interactions with the fungi.
C) their own feces.
D) interactions with a smaller ant species.
E) an enzyme produced by their sweat glands.

Question 17

Which relationship is not a consumer-resource interaction?

A) Competition
B) Predation
C) Parasitism
D) Herbivory
E) All of the above are types of consumer-resource interactions.

Question 18

Which type of interaction is typically random and brief?

A) Amensalism
B) Commensalism
C) Competition
D) Mutualism
E) Predation

Question 19

Which interspecific interaction has negative effects for both species involved?

A) Parasitism
B) Commensalism
C) Amensalism
D) Herbivory
E) Competition

Question 20

Two species of beetles are both herbivores on the same host plant,and the presence of either beetle species reduces the population growth of the other.The relationship between these beetles is best described as

A) commensalism.
B) predation.
C) herbivory.
D) amensalism.
E) competition.

Question 21

Use the following to answer questions :
At low densities and in the absence of any other beetle species,the population of a strain of the flour beetle called Tribolium castaneum grows at a per capita rate of 0.25 per week.In controlled lab conditions,this growth rate is reduced by 0.01 for every 100 individuals.The addition of a related beetle,Tribolium freemani,further reduces the per capita growth rate of T.castaneum by 0.03 for every 100 T.freemani individuals.
If there are 1,000 T.castaneum and 400 T.freemani individuals,what is the per capita growth rate per week of the T.castaneum population?

A) -0.02
B) 0.03
C) 0.11
D) 0.15
E) 0.34

Question 22

Use the following to answer questions :
In Joseph Connell's experiments with barnacles in the intertidal zone,he removed two species from their usual zones (stellate barnacles on the upper levels,rock barnacles on the lower levels)and observed the response of the other species.The results showed that stellate barnacles thrived on both levels in the absence of rock barnacles,whereas the rock barnacles remained only on the lower levels.
The distribution of rock barnacles is restricted by

A) desiccation.
B) cold temperatures.
C) predation.
D) competition.
E) parasitism.

Question 23

Use the following to answer questions :
There are two species of microbes,A and B,which can be grown together or separately.If G_A is the per capita growth rate of species A,G_B is the per capita growth rate of species B,D_A is the density of species A,and D_B is the density of species B,the per capita growth rates for each are:
G_A = 0.14 - 0.006 D_A - 0.04 D_B
G_B = 0.05 - 0.008 D_B + 0.009 D_A
The interaction between species A and B most closely resembles

A) competition.
B) a consumer-resource interaction,where A is the resource and B is the consumer.
C) a consumer-resource interaction,where B is the resource and A is the consumer.
D) mutualism.
E) commensalism.

Question 24

C.F.Gause based his experimental studies of competition primarily on

A) bacteria.
B) yeast.
C) protists.
D) worms.
E) flies.

Question 25

Given a population of 1,000 T.castaneum individuals,how many individuals of T.freemani would be needed to reduce the per capita growth rate of the T.castaneum population to zero?

A) 100
B) 333
C) 500
D) 833
E) 1,500

Question 26

Bear population growth rates are affected by both intraspecific competition and the supply of their prey (in this case,salmon).Assume that the per capita growth rate is equal to 0.0025 S - 0.02 B,where S is the number of salmon that flow into the river and B is the number of bears in the population.If there are 100 bears,what is the minimum number of salmon that must flow into the river to maintain the bear population?

A) 50
B) 80
C) 500
D) 800
E) 1,250

Question 27

Use the following to answer questions :
There are two species of microbes,A and B,which can be grown together or separately.If G_A is the per capita growth rate of species A,G_B is the per capita growth rate of species B,D_A is the density of species A,and D_B is the density of species B,the per capita growth rates for each are the following:
G_A = 0.18 - 0.019 D_A + 0.008 D_B
G_B = 0.22 - 0.012 D_B + 0.005 D_A
If the density of A is 10 and the density of B is 20,the growth rate(s)of

A) A and B are both positive.
B) A is positive and of B is zero.
C) A is positive and of B is negative.
D) A is negative and of B is positive.
E) A and B are both negative.

Question 28

A population of plants has a per capita growth rate of -0.15 per year.The presence of a mutualistic earthworm increases the per capita growth rate of the plant by 0.0025 per worm per meter square.What is the minimal density of worms needed to bring the per capita growth rate of the plant to above zero?

A) 16
B) 26
C) 41
D) 61
E) 121

Question 29

What further information is required to determine that the relationship between T.freemani and T.castaneum is one of competition?

A) Increasing densities of T.castaneum decrease the per capita growth rate of T.freemani.
B) T.freemani behaves differently in the presence of T.castaneum.
C) T.castaneum behaves differently in the presence of T.freemani.
D) Increasing densities of T.castaneum increase the per capita growth rate of T.freemani.
E) No further information is required;the two beetles are engaged in competition.

Question 30

In the absence of rodent herbivores,the per capita population growth rate of a plant in a certain area is 0.06 per year.After the arrival of a population of 500 rodents,the per capita growth rate is -0.02.Assuming that the effect of the rodents on the plants is linear,what is the maximum number of rodents that could be in the area and still allow the plants to have a positive population growth rate?

A) 0
B) 124
C) 374
D) 499
E) 724

Question 31

Use the following to answer questions :
At low densities and in the absence of any other beetle species,the population of a strain of the flour beetle called Tribolium castaneum grows at a per capita rate of 0.25 per week.In controlled lab conditions,this growth rate is reduced by 0.01 for every 100 individuals.The addition of a related beetle,Tribolium freemani,further reduces the per capita growth rate of T.castaneum by 0.03 for every 100 T.freemani individuals.
If all of the T.freemani were removed and there were just 1,000 T.castaneum individuals,what would be the weekly per capita growth rate of the T.castaneum population?

A) 0.01
B) 0.03
C) 0.11
D) 0.15
E) 0.25

Question 32

Use the following to answer questions :
There are two species of microbes,A and B,which can be grown together or separately.If G_A is the per capita growth rate of species A,G_B is the per capita growth rate of species B,D_A is the density of species A,and D_B is the density of species B,the per capita growth rates for each are the following:
G_A = 0.18 - 0.019 D_A + 0.008 D_B
G_B = 0.22 - 0.012 D_B + 0.005 D_A
The interaction between species A and B most closely resembles

A) competition.
B) a consumer-resource interaction,where A is the resource and B is the consumer.
C) a consumer-resource interaction,where B is the resource and A is the consumer.
D) commensalism.
E) mutualism.

Question 33

Intraspecific competition and herbivory by deer are both factors affecting the population growth rate of a bushy plant.Assume the following variables: the per capita growth rate of the bush is 0.1 when population density is very low;c is the rate per individual plant per meter square by which the population rate decreases due to competition;B is the density of plants per meter square;p is the rate by which individual deer reduce the per capita growth rate of the plant;and D is the number of deer.If G is the growth rate of the plants after accounting for intraspecific competition and predation,what is the equation for G?

A) G = 0.1 + cB - pD
B) G = 0.1 - cB + pD
C) G = 0.1 - cD + pB
D) G = 0.1 - cD - pB
E) G = 0.1 - cB - pD

Question 34

Two species of beetles have partially overlapping distributions,with the range of species A extending farther north and the range of species B extending farther south.The distribution of species B is limited mainly by cold temperatures,while that of species A is limited mainly by competition from species B.Given these parameters,the distribution of species _______ would most likely move farther _______ if the other species went extinct.

A) A;north
B) A;south
C) B;north
D) B;south
E) Neither species could adjust its range if the other went extinct.

Question 35

In Joseph Connell's studies of rock barnacles and Poll's stellate barnacles,the limiting resource was shown to be

A) salinity.
B) plankton.
C) space.
D) glucose.
E) sunlight.

Question 36

Which type of species interaction is least likely to lead to a local extinction of at least one of the species involved?

A) Competition
B) Consumer-resource where the consumer is a parasite
C) Consumer-resource where the consumer is a predator
D) Consumer-resource where the consumer is an herbivore
E) Mutualism

Question 37

Which participant would receive an increase in its population growth rate from a given interspecific interaction?

A) A resource in a consumer-resource interaction
B) A consumer in a consumer-resource interaction
C) A competitor in a competition interaction
D) A participant in an amensal relationship
E) None of the above

Question 38

In the absence of fox predation,the per capita growth rate of a population of rabbits is 0.15 per year.If each fox reduces the per capita growth rate of the rabbits by 0.0003,what is the maximum number of foxes that could exist and still allow the rabbit population to have a positive growth rate?

A) 14
B) 49
C) 149
D) 249
E) 499

Question 39

Use the following to answer questions :
In Joseph Connell's experiments with barnacles in the intertidal zone,he removed two species from their usual zones (stellate barnacles on the upper levels,rock barnacles on the lower levels)and observed the response of the other species.The results showed that stellate barnacles thrived on both levels in the absence of rock barnacles,whereas the rock barnacles remained only on the lower levels.
The distribution of stellate barnacles is restricted by

A) desiccation.
B) cold temperatures.
C) predation.
D) competition.
E) parasitism.

Question 40

Use the following to answer questions :
There are two species of microbes,A and B,which can be grown together or separately.If G_A is the per capita growth rate of species A,G_B is the per capita growth rate of species B,D_A is the density of species A,and D_B is the density of species B,the per capita growth rates for each are:
G_A = 0.14 - 0.006 D_A - 0.04 D_B
G_B = 0.05 - 0.008 D_B + 0.009 D_A
If the density of A is 10 and the density of B is 6,the growth rate(s)of

A) A and B are both positive.
B) A is positive and of B is zero.
C) A is positive and of B is negative.
D) A is negative and of B is positive.
E) A and B are both negative.

Question 41

Which of the following is most likely to be eaten by a secondary consumer?

A) Grass
B) Berries
C) Elk
D) Wolves
E) Both a and b

Question 42

Organisms that receive their energy from several trophic levels are said to be

A) carnivores.
B) herbivores.
C) primary consumers.
D) secondary consumers.
E) omnivores.

Question 43

Which activity could be an example of restoration ecology?

A) Reintroducing wolves to an area where they formerly occurred
B) Determining the effect two mutualists have on each other's reproductive rates
C) Determining the indirect effect the removal of lions has on plants via trophic cascades
D) Introducing a novel pathogen to help control the spread of gypsy moths and eliminate native caterpillars that damage commercial timber
E) Removing wolves from a national park to restore elk populations for hunters

Question 44

Which of the following is a primary consumer?

A) A predatory fish
B) A detritus-eating roundworm
C) An oak tree
D) A herbivorous beetle larva
E) None of the above

Question 45

What types of organisms do autotrophs feed on?

A) Primary producers
B) Primary consumers
C) Secondary consumers
D) Decomposers
E) No organisms

Question 46

A species of spider that typically feeds on herbivorous insects is a(n)

A) primary consumer.
B) tertiary consumer.
C) autotroph.
D) herbivore.
E) secondary consumer.

Question 47

Organisms that acquire their energy from eating primary consumers are

A) primary producers.
B) secondary consumers.
C) herbivores.
D) autotrophs.
E) decomposers.

Question 48

What type of organisms would be two trophic levels removed from autotrophs?

A) Primary producers
B) Primary consumers
C) Secondary consumers
D) Tertiary consumers
E) Herbivores

Question 49

Which process is most likely to lead to intraspecific competition being stronger than interspecific competition?

A) Amensalism
B) Trophic cascading
C) Autotrophic depletion
D) The Muir effect
E) Resource partitioning

Question 50

Two similar species of lemurs exist in Madagascar.One species eats leaves from the understory of trees,and the other eats leaves from the top of the trees.This phenomenon would be best described as

A) competitive exclusion.
B) commensalism.
C) resource partitioning.
D) consumer-resource.
E) amensalism.

Question 51

If secondary consumers are the highest trophic level in a community,how many trophic levels does that community have (not counting decomposers)?

A) Two
B) Three
C) Four
D) Three if it is an aquatic community,four if it is a terrestrial community
E) Three if it is a terrestrial community,four if it is an aquatic community

Question 52

John Muir said,"When we try to pick out anything by itself,we find it hitched to everything else in the Universe." Which process comes most closely to the idea expressed in Muir's statement?

A) Resource partitioning
B) Evolutionary arms races
C) Biological barter
D) Trophic cascades
E) Rarity advantage

Question 53

By definition,autotrophs are

A) primary consumers.
B) primary producers.
C) secondary consumers.
D) secondary producers.
E) decomposers.

Question 54

A primary consumer

A) is an herbivore.
B) is an autotroph.
C) eats secondary consumers.
D) is a carnivore.
E) eats herbivores.

Question 55

The effect that the removal of wolves from Yellowstone National Park had on aspen is best described as

A) the result of resource partitioning.
B) an amensalism.
C) a resource-consumer relationship.
D) the consequence of a trophic cascade.
E) an evolutionary arms race.

Question 56

Refer to the figure below showing a food web in the grasslands of Yellowstone National Park.Based on the relationships shown,which trophic cascade would most likely result from the removal of gray wolves? [Note: Red arrows refer to animals consumed by carnivores;blue arrows correspond to plants consumed by omnivores and herbivores.]

A) Removal of gray wolves leads to fewer elk,which leads to more snowshoe hares.
B) Removal of gray wolves leads to fewer elk,which leads to fewer snowshoe hares.
C) Removal of gray wolves leads to more bison,which leads to fewer snowshoe hares.
D) Removal of gray wolves leads to fewer coyotes,which leads to fewer deer mice.
E) Removal of gray wolves leads to more coyotes,which leads to fewer deer mice.

Question 57

In a food web with energy flowing up,a(n)_______ is one trophic level above a primary consumer.

A) primary producer
B) decomposer
C) herbivore
D) autotroph
E) secondary consumer

Question 58

Two species are most likely to coexist despite competition between them when

A) a nonfood item is the limiting resource.
B) a food item is the limiting resource.
C) interspecific competition is stronger than intraspecific competition.
D) a species gains a growth advantage when it is common.
E) intraspecific competition is stronger than interspecific competition.

Question 59

When two species are competitors,rarity advantage is likely to lead to

A) the extinction of one of the species.
B) coexistence of both species.
C) an evolution of the competitive interaction into a resource-host interaction.
D) an evolution of the competitive interaction into a mutualism.
E) extinction of both species.

Question 60

Why did the elimination of wolves from Yellowstone National Park lead to a large reduction in the size of the aspen population?

A) Wolves and aspen are in a mutualistic relationship.
B) The absence of wolves led to large populations of elk,which consume the aspen.
C) The absence of wolves led to small populations of elk,and elk and aspen are in a mutualistic relationship.
D) The absence of wolves led to large populations of beavers,which consume the aspen.
E) Wolves and aspen are in a consumer-resource relationship.

Question 61

A population of birds colonizes an area and eats seeds in that locale.Over the course of evolution,the variability of birds eating seeds has decreased and the birds become more efficient at converting seeds into energy.Likely,______ selection has been operating,and has caused a(n)_______ in the carrying capacity.

A) disruptive;increase
B) disruptive;decrease
C) stabilizing;increase
D) stabilizing;decrease
E) directional;decrease

Question 62

Which pairs of species are participating in mutualistic interactions in which one type of nutrient is exchanged for another?

A) Human and gut bacteria
B) Plant and pollinator
C) Fruit tree and frugivore
D) Leaf-cutter ant and green mold
E) Leaf-cutter ant and plant

Question 63

Which process is most responsible for the biochemical diversity of plants,including those that produce compounds that humans use for spices?

A) Adaptations to different soils
B) Adaptations to different temperature regimes
C) Adaptations to different levels of moisture
D) Evolutionary arms races with herbivores
E) Evolutionary arms races with commensals

Question 64

Which activity would you not expect to see in a mutualism?

A) Cheating
B) Biological barter
C) Resources and services provided by one species solely for the benefit of another species
D) Individuals acting to promote their own self-interest
E) More than two species participating

Question 65

Which statement about interspecific competition is false?

A) It can lead to evolutionary changes in size.
B) It can lead to evolutionary changes in type of diet.
C) Individuals within species vary with respect to their sensitivity to interspecific competition.
D) It can lead to resource partitioning.
E) All of the above are true;none is false.

Question 66

A beetle that was introduced to Hawaii some time ago,has rapidly increased in number,and now causes damage to native vegetation would be considered

A) commensal.
B) amensal.
C) endemic.
D) evasive.
E) invasive.

Question 67

The American chestnut

A) was drastically reduced in population size by an invasive pathogen.
B) has prospered due to the introduction of a mutualist.
C) was nearly driven to extinction by an invasive herbivore.
D) is an invasive species.
E) is required for the spread of Lyme disease.

Question 68

Suppose a survey of predator-prey relationships where the predators were large mammals shows that the fastest predators are usually found in regions where the fastest prey are also found.The most likely explanation for such a finding would be

A) resource partitioning.
B) the existence of evolutionary arms races.
C) that the predator-prey relationship has evolved into a mutualism.
D) that the predator-prey relationship has evolved into an amensalism.
E) the Muir principle.

Question 69

Which invasive species is harmful to native species because it crowds them out?

A) Platte thistle
B) American chestnut
C) Sac fungus
D) Yellow star-thistle
E) Elk

Question 70

Invasive species

A) usually perform less well than native species because they lack adaptations to counter predators.
B) usually perform less well than native species because they lack adaptations to counter pathogens.
C) can harm native species that lack adaptations to counter the competing invasive.
D) usually reproduce slowly.
E) do not spread from their original point of introduction.

Question 71

The passionflower plant has developed leaf structures that look like a butterfly's egg because these structures

A) attract mutualists.
B) deter herbivores.
C) reduce competition.
D) enable the plant to obtain light energy more efficiently.
E) benefit another species.

Question 72

Which statement about mutualisms is true?

A) They can be obligate,one-on-one relationships.
B) They can be diffuse relationships that involve many species.
C) Their evolutionary consequences are easy to predict.
D) They involve altruism.
E) Both a and b

Question 73

Which statement about mutualisms is false?

A) They can evolve into consumer-resource relationships.
B) Darwin thought mutualisms were an example of structures of one species evolving for the exclusive good of another.
C) They involve biological barter.
D) Their evolutionary consequences are hard to predict.
E) The net effect of a mutualism on fitness may vary depending on environmental conditions.

Question 74

Where or when would you most likely see mutualistic relationships between plants and mycorrhizal fungi?

A) In nutrient-rich soils
B) In nutrient-poor soils
C) When bees are robbing flowers
D) When the mycorrhizal fungi are being altruistic
E) When the plants are being altruistic

Question 75

Which statement about Heliconius butterflies,which are poisonous to many of their predators,is true?

A) They have elaborate biochemical pathways that produce a cyanide-like toxin.
B) They have elaborate biochemical pathways that produce a toxin that resembles the capsaicins of chilies.
C) They obtain toxins from the passionflower vines on which they feed.
D) They obtain toxins from the cabbages on which they feed.
E) They obtain toxins from a symbiont bacterium.

Question 76

In a mutualism between a fruit tree and a frugivore,the tree provides _______ in exchange for _______.

A) food;protection
B) food;seed dispersal
C) protection;seed dispersal
D) protection;food
E) one type of nutrient;another type of nutrient

Question 77

The statement "It takes all the running you can do,just to keep in the same place" describes in colloquial terms to the phenomenon of

A) evolutionary arms races.
B) resource portioning.
C) rarity advantage.
D) mutualism.
E) trophic cascades.

Question 78

A species of mouse mainly eats grasses.Individuals of this species are smaller in locations where it co-occurs with a second,larger rodent species that also eats grass than in locations without that larger rodent.What is the most likely cause of this difference?

A) A trophic cascade
B) An evolutionary arms race
C) A mutualism evolving into a consumer-resource relationship
D) A consumer-resource relationship evolving into a mutualism
E) Resource partitioning

Question 79

An indigenous population in South America uses small quantities of a plant substance as a spice to enhance the taste of food.In larger quantities,this substance can be toxic.What is the likely evolutionary explanation for this substance?

A) It is the result of resource partitioning.
B) It is a defensive compound.
C) It evolved as the result of a mutualism.
D) It evolved to enable the plant to obtain light energy more efficiently.
E) It is the result of a trophic cascade.

Question 80

Evolutionary "arms races" are usually the result of

A) consumer-resource interactions.
B) amensalisms.
C) responses to abiotic conditions.
D) commensalisms.
E) genetic drift.