Exercise 12 Flashcards
(22 cards)
Why do carnivores tend to be generalists and have broad diets?
Encounter rate is high and handling time is low, which favors broad prey choices.
Encounter rate is low and handling time is high, which favors broad prey choices.
Encounter rate and handling time is low, which favors broad prey choices.
Encounter rate and handling time is high, which favors broad prey choices.
Encounter rate and handling time is low, which favors broad prey choices.
Why do some carnivores engage in prey switching?
Given that they are specialists, they will switch to the least available prey.
Given that they are generalists, they will switch to the most available prey.
Given that they are generalists, they will forage on all available prey.
Given that they are specialists, they will switch to the most available prey.
Given that they are generalists, they will switch to the most available prey.
Why do herbivores tend to be specialists and have narrow diets?
Encounter rate is high and handling time is low, which favors narrow prey choices.
Encounter rate is low and handling time is high, which favors narrow prey choices.
Encounter rate and handling time is low, which favors broad prey choices.
Encounter rate and handling time is high, which favors broad prey choices.
Encounter rate and handling time is high, which favors broad prey choices.
Which mechanism do animals NOT use to avoid being eaten?
Large size
Resembling a less palatable animal
Mimicking an organism or background to remain hidden
Changing their behavior to make them more noticeable correct
Changing their behavior to make them more noticeable correct
Which mechanism(s) do plants use to avoid being eaten?
Secondary compounds that are toxic or reduce nutrition
Structural defenses such as spines or hairs
Compensation by stimulating new plant growth
Both a and b
Both a and b
Herbivores can overcome plant defenses in which of the following ways?
Evolve digestive enzymes to tolerate plant chemical defense
Evolve behaviors that strengthen plant defenses
Evolve toxins that kill the plant
Both b and c
Evolve digestive enzymes to tolerate plant chemical defense
What does the Lotka–Volterra predator–prey model suggest about trophic interactions?
Predator and prey populations cycle when the abundance of one population is not dependent on the abundance of the other population.
Predator and prey populations cycle when the abundance of one population is dependent on the abundance of the other population.
Predator and prey populations cycle when the predator and prey isoclines intersect.
Predator and prey populations cycle when the predator and prey isoclines intersect.
Predator and prey populations cycle when the abundance of one population is dependent on the abundance of the other population.
How does one determine whether predator and prey populations are cycling?
Solve for the population growth equation of each species when they reach the zero growth isocline.
Plot the isocline for both the prey and predator populations in graphical form.
Both a and b
None of the above
None of the above
What are some factors that do NOT affect whether predator–prey populations cycle?
Evolutionary changes to the prey population
The dependence of predator and prey population abundances on one another
The initial and ending numbers of predators and prey
Habitat complexity, predator dispersal, and spatial refuges of the prey
The initial and ending numbers of predators and prey
How do predators mostly affect the distribution and abundance of their prey?
By directly affecting the prey of the prey
By indirectly affecting the prey of the prey
By increasing the growth, survival, and/or reproduction of the prey
By reducing the growth, survival, or reproduction of the prey
By reducing the growth, survival, or reproduction of the prey
Which example from the chapter shows how predators act through direct means to alter communities?
Sea stars and mussels
Golden apple snails and wetland plants
Geese feeding on marsh plants after the 1970s
Foxes feeding on seabirds
Geese feeding on marsh plants after the 1970s
Which example from the chapter shows how predators act through indirect means to alter communities?
Lizards feeding on spiders
Golden apple snails and wetland plants
Geese feeding on marsh plants after the 1970s
Beetles feeding on Klamath weed
Golden apple snails and wetland plants
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?
Lynx can move great distances.
Only some, but not all, predators were excluded in the treatment.
Excess food supplies were removed prior to the end of the experiment.
Hares experienced an unexpected viral disease.
Only some, but not all, predators were excluded in the treatment.
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
below 50.
equal to 50.
above 50.
between 50 and 100.
below 50.
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 _______.
increase; communities of small shrubs and forbs
increase; tundra
decrease; communities of small shrubs and forbs
decrease; alpine forest
decrease; communities of small shrubs and forbs
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 decrease; a decrease
an increase; a decrease
an increase; no change
no change; no change
a decrease; a decrease
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?
Whether natural selection was operating to influence the population cycles
The complexity of the habitat
The nature of the prey’s stress response
Whether the predators were “sit-and-wait” or active
The complexity of the habitat
Females in the wasp genus Nasonia typically lay eggs in the pupa of blowflies (species in the Calliphoridae family). The wasp eggs hatch into larvae, and the larvae kill and eat the fly pupa. Based on these observations, which statement is false?
The wasps and the blowflies are engaged in a predatory relationship.
The wasps are parasitoids.
The wasps can be thought of as both predators and parasites, albeit unusual ones.
The wasps are generalist.
The wasps are generalist.
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.
exploitative
cryptic
apomitic
aposematic
aposematic
Insects feeding on the leaves of a plant stimulate the plant to produce more leaves. This is an example of _____.
aposematism
compensation
competition
an induced defense
compensation
How do predation and herbivory differ from parasitism and parasitoidism?
Parasitism and parasitoidism are not exploitative relationships.
Most parasites and parasitoids spend their entire lives consuming a single individual, whereas herbivores and predators usually eat at least several different individuals.
Unlike parasitoids and parasites, predators and herbivores usually do not exert strong selective pressures on their food organisms.
Parasitism never results in the death of the organism, while predation and herbivory usually do cause the death of the organisms they eat.
Most parasites and parasitoids spend their entire lives consuming a single individual, whereas herbivores and predators usually eat at least several different individuals.
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 _____.
crypsis
an induced defense
aposematic coloration
silencing
crypsis
