Deck 12: Predation

Question 1

Which observation led ecologists to conclude that resource limitation is not the only factor driving snowshoe hare cycles?

A) Some declining hare populations do not lack food.
B) Experimental addition of high quality food prevents hare populations from declining.
C) Hare reproductive rates peak several years before densities reach a maximum.
D) Hare population sizes rose and fell in synchrony across broad regions of the Canadian forest.

Answer 1

A

Question 2

Which statement about parasitoids is false?

A) Most parasitoids kill their hosts.
B) Parasitoids lay eggs in or on another insect.
C) Parasitoid larvae do not eat the host insect.
D) Parasitoid larvae remain in the host insect.

Answer 2

C

Question 3

Females in the wasp genus Nasonia typically lay eggs in the pupa of blowflies. The wasp eggs hatch into larvae, and the larvae kill and eat the fly pupa. Based on these observations, which statement is false?

A) The wasps and the blowflies are engaged in a predatory relationship.
B) The wasps are parasitoids.
C) The wasps can be thought of as both predators and parasites, albeit unusual ones.
D) The wasps are generalist.

Answer 3

D

Question 4

Which of the following is not a difference between herbivores and carnivores?

A) Carnivores kill their prey, while herbivores do not.
B) Animal prey can be hard to find, while plants are not.
C) Animal prey is much less nutritious than plant prey.
D) Herbivores typically eat only a small part of the plant and carnivores eat the whole animal.

Question 5

Refer to the figure.
Based on data in the figure, a newly discovered seed could be hypothesized to have a nitrogen content of _______?

A) 0.003
B) 0.03
C) 0.3
D) 3

Question 6

Refer to the figure.
The figure shows the relationship between the relative proportion of prey type A that is available in an area and the proportion of prey type A in the total diet of three different predators. Which predator shows evidence that it prefers to eat the more common prey?

A) Predator 1 only
B) Predator 2 only
C) Predator 3 only
D) Both predator 1 and predator 2

Question 7

Herbivores most commonly eat the _______ of plants.

A) leaves
B) stems
C) roots
D) seeds

Question 8

Larvae of agromyzid flies are typical of herbivorous insects. They feed off of _______ and tend to have _______ diets.

A) leaves; broad
B) leaves; narrow
C) stems; broad
D) stems; narrow

Question 9

Which statement about predators and prey is true?

A) Mimicry is found only in prey, not in predators.
B) The body form of the cheetah enables it to have great bursts of speed, improving its likelihood of capturing gazelles and other prey.
C) Prey capture is facilitated in snakes by the rigid connections among their skull bones.
D) Only herbivores have anti-predator defenses.

Question 10

Many species of butterflies are noxious to predators. They also have bright red coloration that indicates to the potential predators that they are unpleasant or even harmful to eat. This is an example of _______ coloration.

A) exploitative
B) cryptic
C) apomitic
D) aposematic

Question 11

Moths resting on the trunks of trees often resemble the tree bark so that potential predators do not perceive them as prey. This is an example of

A) crypsis.
B) an induced defense.
C) aposematic coloration.
D) silencing.

Question 12

How do Lembadion bullinum change in response to their prey?

A) They evolve aposematic coloration.
B) They become more cryptic.
C) They alter their size to match the size of available prey.
D) They produce more secondary compounds.

Question 13

Different species of marine snails that are preyed on by a shore crab differ in terms of how easily the crab can crush their shells. Studies of these snails have provided evidence for the

A) value of "gene silencing" in ecological studies.
B) principle of compensation.
C) presence of trade-offs between different antipredator adaptations.
D) influence of exploitation in the distribution and abundance of food organisms.

Question 14

Refer to the figure.


- A new hypothetical species of green crabs is discovered that has a handling time of 2.4. Based on other green crabs' behavior, you hypothesize that the new species predator avoidance response index will be approximately

A) 0.
B) 3.
C) 10.
D) 15.

Question 15

Refer to the figure.


-A student is asked to determine which species of green crab they have found based on the predator avoidance response index. After three independent trials, the average predator avoidance response index was determined to be 12. Which species has the student been studying?

A) Littorina littorea
B) Gibbula cineraria
C) Osilinus lineatus
D) Gibbula umbilicalis

Question 16

Huge numbers of adult periodic cicadas emerge simultaneously from pupae at intervals of either 13 or 17 years. This phenomenon is most similar to which of the following?

A) Masting
B) Compensation
C) Induced defense
D) Aposematism

Question 17

Insects feeding on the leaves of a plant stimulate the plant to produce more leaves. This is an example of

A) aposematism.
B) compensation.
C) competition.
D) an induced defense.

Question 18

In the studies of clipping in gentians, plants that were clipped early in the season had _______ number of fruits, and plants that were clipped late in the season had _______ number of fruits.

A) the highest; an intermediate
B) the highest; the lowest
C) an intermediate; the highest
D) the lowest; the highest

Question 19

The secondary compounds that are produced by oaks to reduce herbivory are an example of a(n)

A) compensation.
B) aposematism.
C) induced defense.
D) mimicry.

Question 20

Which of the following is not a way tobacco plants respond to herbivory?

A) They deter herbivores directly.
B) They deter herbivores indirectly.
C) They produce volatile compounds that attract predators and parasitoids of the herbivores.
D) They generate a toxic, sticky resin to coat predators.

Question 21

Züst and colleagues found that

A) plants with aphids and without aphids (control) grew the same.
B) there was a decrease in average plant size that was associated with no changes in genotypic composition.
C) rapid evolution may have occurred in the plant population.
D) random selection accounted for the difference in plant genotypes, not aphids.

Question 22

Based on Züst and his colleagues' findings, herbivory

A) can cause evolution of plant populations.
B) never affects evolution rates of plant populations.
C) does not have a cost associated with it.
D) results in a decline in evolution.

Question 23

In the Lotka‒Volterra predator‒prey model, the parameter a represents the

A) birth rate of prey.
B) population growth rate of prey in the absence of predators.
C) efficiency with which prey biomass is converted into predator offspring.
D) capture efficiency of prey by predators.

Question 24

Suppose that rabbits are the only prey and food supply of foxes, and that the predator‒prey interaction follows Lotka‒Volterra dynamics. The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits in the absence of predation is 0.2 per week. The capture efficiency is 0.002, and the efficiency at which rabbit biomass is converted into fox biomass is 0.2. If there are 30 foxes in a population, and 400 rabbits are present, the rate at which prey will be killed is _______ per week.

A) 24
B) 30
C) 80
D) 120

Question 25

Suppose that rabbits are the only prey and food supply of foxes, and that the predator‒prey interaction follows Lotka‒Volterra dynamics. The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits in the absence of predation is 0.2 per week. The capture efficiency is 0.002, and the efficiency at which rabbit biomass is converted into fox biomass is 0.2.If there are initially 30 foxes and 400 rabbits, the overall rate of change in the rabbit population will be a _______ of _______ per week.

A) loss; 24
B) loss; 16
C) gain; 56
D) gain; 80

Question 26

Suppose that rabbits are the only prey and food supply of foxes, and that the predator‒prey interaction follows Lotka‒Volterra dynamics. The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits in the absence of predation is 0.2 per week. The capture efficiency is 0.002, and the efficiency at which rabbit biomass is converted into fox biomass is 0.2. If there are initially 30 foxes and 400 rabbits, the net growth rate in the fox population will be a _______ of _______ per week.

A) loss; 3
B) loss; 1.8
C) gain; 1.8
D) gain; 4.8

Question 27

Suppose that rabbits are the only prey and food supply of foxes, and that the predator‒prey interaction follows Lotka‒Volterra dynamics. The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits in the absence of predation is 0.2 per week. The capture efficiency is 0.002, and the efficiency at which rabbit biomass is converted into fox biomass is 0.2. If the number of rabbits doubles and the number of foxes also doubles, the number of rabbits that are killed will

A) be halved.
B) remain the same.
C) double.
D) quadruple.

Question 28

The Lotka‒Volterra predator‒prey model of population growth

A) does not depend on the availability of the predator's resources.
B) is independent on the prey's resources.
C) does not change when the predator population declines.
D) assumes that when predators are absent the prey population grows exponentially.

Question 29

Suppose that a predatory fish eats only minnows and the predator‒prey interaction follows Lotka‒Volterra dynamics. The intrinsic growth rate of minnows in the absence of predators is 0.2 per month, and the mortality rate of the predatory fish in the absence of minnows is 0.1 per month. The capture efficiency rate is 0.004, and the efficiency at which minnow biomass is converted into predator biomass is 0.25. The minnow population size will increase only if the number of predatory fish is

A) below 50.
B) equal to 50.
C) above 50
D) below 100.

Question 30

Suppose that a predatory fish eats only minnows and the predator‒prey interaction follows Lotka‒Volterra dynamics. The intrinsic growth rate of minnows in the absence of predators is 0.2 per month, and the mortality rate of the predatory fish in the absence of minnows is 0.1 per month. The capture efficiency rate is 0.004, and the efficiency at which minnow biomass is converted into predator biomass is 0.25. The predatory fish population will increase only if the number of minnows is

A) above 50.
B) above 100.
C) below 50.
D) below 100.

Question 31

Refer to the figure.
The figure shows the interaction between predator abundance and prey abundance. Populations of lynx and hares are located at the star. Based on the Lotka-Volterra predator-prey model, we would expect the number of prey to _______ and the number of predators to _______.

A) increase; increase
B) increase; decrease
C) decrease; increase
D) decrease; stay the same

Question 32

In Huffaker's studies of an herbivorous mite and its mite predator, when predator and prey were in a simple environment,

A) prey and predator populations both increased for a while, but soon crashed and went extinct.
B) prey soon went extinct, but predators persisted.
C) predators soon went extinct, but prey persisted.
D) predators and prey persisted and exhibited population cycles.

Question 33

In Huffaker's studies of an herbivorous mite and its mite predator, when predator and prey were in a heterogeneous environment,

A) prey and predator populations both increased for a while, but soon crashed and went extinct.
B) predators soon went extinct, but prey persisted.
C) predators and prey persisted, and maintained relatively stable population sizes.
D) predators and prey persisted and exhibited population cycles.

Question 34

Refer to the figure.
On which date(s) was the predator's density 20?

A) March 30 and April 13
B) March 20 and April 20
C) April 20 only
D) March 15

Question 35

All of the following factors can prevent predators from driving prey to extinction except

A) habitat complexity.
B) limited predator dispersal.
C) marine extension.
D) spatial refuges.

Question 36

Which statement about the study of the invasive Klamath weed and a leaf-feeding beetle is true?

A) Plant populations cannot be reduced through herbivory.
B) A leaf-feeding beetle reduced the density of an invasive weed.
C) Both Klamath and the Chrysolina beetle are invasive.
D) Chrysolina beetle density remained indefinitely high after the decline in Klamath weed population.

Question 37

Schoener and Spiller's studies, in which lizards were introduced into islands in the Bahamas, showed that lizards _______ the densities of common spiders and _______ the densities of rare spiders.

A) decreased; decreased
B) increased; decreased
C) decreased; increased
D) increased; increased

Question 38

Which statement best describes the relationship between snow geese and plants in the salt marshes that border the Hudson Bay?

A) At all densities, the geese benefit the plants.
B) At all densities, the geese harm the plants.
C) At low densities, the geese benefit the plants; at high densities, the geese harm the plants.
D) At low densities, the geese harm the plants; at high densities, the geese benefit the plants.

Question 39

The introduction of arctic foxes to some of the Aleutian Islands led to a drastic _______ in nitrogen-rich guano, and this change had the effect of transforming the islands from grassland to _______.

A) increase; communities of small shrubs and forbs
B) increase; tundra
C) decrease; communities of small shrubs and forbs
D) decrease; alpine forest

Question 40

In the salt marshes bordering the Hudson Bay, the addition of snow geese to areas with no snow geese would likely _______ the marshes because geese _______. The addition of more geese to areas that already have large numbers of geese would likely _______ the marshes.

A) benefit; add nutrients; benefit
B) benefit; eat herbivores; harm
C) benefit; add nutrients; harm
D) harm; defecate; harm

Question 41

Which of the following would likely result from a decrease in the density of the golden apple snail in an area that previously had large snail populations?

A) The biomass of aquatic plants would increase.
B) Nutrient content would increase.
C) Phytoplankton density would increase.
D) No changes would be observed.

Question 42

In Krebs and colleagues' study of snowshoe hare cycles, which of the following was a plausible reason for the failure of the "+Food/‒Predator" treatment to stop hare population declines late in the cycle?

A) Lynx can move great distances.
B) Only some, but not all, predators were excluded in the treatment.
C) Excess food supplies were removed prior to the end of the experiment.
D) Hares experienced an unexpected viral disease.

Question 43

Refer to the figure.
What year was the +Food/-Predators hare density 400/km² and decreasing?

A) 1989
B) 1990
C) 1991
D) 1992

Question 44

When animals are exposed to chronic stress, the stress response suppresses all of the following except

A) growth.
B) reproduction.
C) the immune response.
D) release of glucose.

Question 45

The hormone _______ stimulates the release of stored glucose to make it available to muscles.

A) immunoglobin
B) estrogen
C) cortisol
D) pituitary release hormone

Question 46

Refer to the figure.
You are studying the composition of the diet of a predator species. Among other prey, this predator preys upon species A. You collect data on how species A's abundance is related to the percent of the predator's diet composed of this species. Based on the figure, at which point would predator consumption patterns match the predicted consumption patterns if the predator's percent of consumption matched the percent of species A in terms of total prey base?

Question 47

Refer to the figure.
You are studying the composition of the diet of a predator species. Among other prey, this predator preys upon species A. You collect data on how species A's abundance is related to the percent of the predator's diet composed of this species. Based on the figure, at what percent of species A is the predator's diet comprised of 50% species A and 50% other prey?

Question 48

The popular rhyme to distinguish the scarlet king snake (Lampropeltis elapsoides) from the venomous eastern coral snake (Micrurus fulvius) goes "red touching black - pat it on the back; red touching yellow - kills a fellow". Explain the type(s) of defense the scarlet king snake exhibits and an energetic advantage of this type of defense to the scarlet king snake.

Question 49

Military camouflage is analogous to what type of biological defense against predation? Explain how camouflage works as a defense.

Question 50

Department of Natural Resource managers, biologists, and foresters in many states work together to successfully manage game populations by determining the number of deer, bear or other animals that can be harvested each year. Harvest numbers can fluctuate based on climatic factors and natural events that affect plant production. For example, squirrels have been documented to have additional litters in masting years. Additionally, in the years following oak tree mastings, the number deer and squirrels that can be harvested tends to increase. Explain why mastings can influence deer and squirrel populations and the benefit of them to the oak tree.

Question 51

You are studying two species in a community: a carnivorous predator and a herbivorous prey species. When analyzing the data, you realize the population size of the predators is very similar to the population size of the prey. What makes this unusual?

Question 52

Use the following simple predator-prey relationships to answer the question (assume no other interactions exist in this system): Mice eat grain grown by a farmer before it can be harvested. The mice are consumed by several species of snakes, which themselves are consumed by hawks. If the population of snakes was suddenly wiped out by disease, explain the short-term effects on the grain, mice, and hawk populations, and why these effects would be observed.

Question 53

Use the following simple predator-prey relationships to answer the question (assume no other interactions exist in this system): Mice eat grain grown by a farmer before it can be harvested. The mice are consumed by several species of snakes, which themselves are consumed by hawks. If the population of snakes were suddenly wiped out by disease, explain the long-term effects on the grain, mice, and hawk populations, and why these effects would be observed.

Question 54

Use the following simple predator-prey relationships to answer the question (assume no other interactions exist in this system): Mice eat grain grown by a farmer before it can be harvested. The mice are consumed by several species of snakes, which themselves are consumed by hawks. Local farmers would like to use a biological, as opposed to a chemical, means to protect their crop. What would be the most effective way for farmers in this area to protect their grain crop naturally? Why?

Question 55

Suppose you are studying the effect of predation on levels of cortisol in a species of mouse in the lab. You set up an experiment in which you house some mice in cages with photographs of rabbits on the walls of their cages; others are housed with photographs of flowers on the walls of their cages; while others are housed with photographs of hawks. The cortisol level in mice blood plasma (nmol/L) after exposure to the photographs measures 190 for rabbits, 475 for hawks, and 185 for flowers. Why did you expose the mice to three different types of photographs? What type of relationship would an individual mouse have with the different plant/animal species pictured? Why did the hawk photograph result in the highest levels of cortisol?

Question 56

How does predation and herbivory differ from parasitism and parasitoidism?

A) Parasitism and parasitoidism are not exploitative relationships.
B) Most parasites and parasitoids spend their entire lives consuming a single individual, whereas herbivores and predators usually eat at least several different individuals.
C) Unlike parasitoids and parasites, predators and herbivores usually do not exert strong selective pressures on their food organisms.
D) Parasitism never results in the death of the organism, while predation and herbivory usually do cause the death of the organisms they eat.

Question 57

Refer to the figure.
The graphs show different relationships between the proportion of prey that are tubificids and the proportion that are eaten by predators (guppies). Based on research by Murdoch et al., which graph best represents the foraging habits of guppies?

A) Graph A
B) Graph B
C) Graph C
D) Graph D

Question 58

Which statement about predators and herbivores is true?

A) A broad diet is more typical of a predator than of an herbivore.
B) Only herbivores eat seeds more than any other plant part.
C) There are few herbivorous insects.
D) Herbivores tend to be generalists and usually forage on many different types of plants.

Question 59

Which statement about garter snakes and TTX is true?

A) Some garter snakes produce TTX.
B) Some garter snakes are resistant to TTX due to TTX-resistant sodium channels in their neurons.
C) Snakes that are resistant to TTX move more quickly than other snakes.
D) Snakes that are resistant to TTX cannot eat newts.

Question 60

Which statement about the effects of herbivory on tobacco is false?

A) Tobacco produces secondary compounds that directly deter herbivores.
B) Tobacco produces secondary compounds that indirectly deter herbivores by attracting predators of the herbivores.
C) None of the secondary compounds produced by tobacco are induced defenses.
D) Tobacco plants' induced defenses are effective in reducing losses of tissue.

Question 61

In the Lotka‒Volterra predator‒prey model, b represents the

A) birth rate of prey.
B) population growth rate of prey in the absence of predators.
C) efficiency at which prey biomass is converted into predator offspring.
D) capture efficiency of prey by predators.

Question 62

In the Lotka‒Volterra predator‒prey model, an increase in the capture efficiency (a) should lead to _______ in the long-term average number of predators and _______ in the long-term average number of prey.

A) an increase; a decrease
B) an increase; no change
C) a decrease; a decrease
D) no change; no change

Question 63

Suppose that a lizard species eats only one type of insect and the populations follow Lotka‒Volterra dynamics. The intrinsic growth rate of insects in the absence of predators is 0.2 per week and the mortality rate of the lizards in the absence of insects is 0.05 per week. The capture efficiency rate is 0.002, and the efficiency at which insect biomass is converted into predator biomass is 0.2. The insect population size will increase only if the number of lizards is

A) above 50.
B) above 100.
C) below 50.
D) below 100.

Question 64

Suppose that a lizard species eats only one type of insect and the populations follow Lotka‒Volterra dynamics. The intrinsic growth rate of insects in the absence of predators is 0.2 per week, and the mortality rate of the lizards in the absence of insects is 0.05 per week. The capture efficiency rate is 0.002, and the efficiency at which insect biomass is converted into predator biomass is 0.2.The lizard population will increase only if the number of insects is

A) above 125.
B) above 500.
C) above 625.
D) below 125.

Question 65

In a predator‒prey system functioning according to Lotka‒Volterra dynamics, an increase in the efficiency (b) by which prey biomass is converted into predator biomass should _______ the long-term average number of prey.

A) decrease
B) have no effect on
C) slightly increase
D) greatly increase

Question 66

In Huffaker's studies of an herbivorous mite and its mite predator, which variable was critical in determining whether the populations of predator and prey would go extinct quickly or persist?

A) Whether natural selection was operating to influence the population cycles
B) The complexity of the habitat
C) The nature of the prey's stress response
D) Whether the predators were "sit-and-wait" or active

Question 67

Croll et al. studied the effects that long-term inhabitation of artic foxes had on the ecosystems of the Aleutian Islands. Based on their findings, which of the following statements is true?

A) Accumulation of guano on the island was not influenced by the introduction and long-term inhabitation of artic foxes.
B) The nitrogen content in the seabirds' guano increased in response to predation.
C) A reduction in the quantity of guano released on the islands inhabited by artic foxes resulted in an ecological shift from grasslands to more shrubs and forbs.
D) Croll et al. concluded that while artic foxes reduced the number of seabirds on the islands, they did not cause the alteration of island ecosystems where they lived.

Question 68

Based on Schoener and Spiller's studies of spider densities in the Bahamas, what is the correct ranking, from highest to lowest, of the probability of spiders going extinct on three different islands: islands on which lizards are absent, islands on which lizards have been introduced, and islands on which lizards are present naturally?

A) Lizards absent > lizards introduced > lizards natural
B) Lizards absent > lizards natural > lizards introduced
C) Lizards introduced > lizards natural > lizards absent
D) Lizards introduced > lizards absent > lizards natural

Question 69

Which statement best describes the relationship between snow geese and plants in the salt marshes that border the Hudson Bay?

A) At all densities, the geese benefit the plants.
B) At all densities, the geese harm the plants.
C) At low densities, the geese benefit the plants; at high densities, the geese harm the plants.
D) At low densities, the geese harm the plants; at high densities, the geese benefit the plants.

Question 70

Which factor most likely explains the synchrony of the hare population cycles in geographically distant areas?

A) Isolation of the lynx
B) Similarity of climate in these geographically distant areas
C) Movement of hares
D) Presence of competitive herbivores