Question 1 of 20
Gause’s “competitive exclusion principle” states that:
A. when two species occur together, competition is always prevented by some behavioral adjustment.
B. no two species can coexist indefinitely.
C. no two competing species can coexist indefinitely.
D. no two species with identical niches can coexist indefinitely.
Question 2 of 20
In the Lotka-Volterra competition equations, if a21 > 1, then:
A. the population growth rate of species 2 is reduced more by each individual of species 1 than by each individual of species 2.
B. the population growth rate of species 2 is reduced more by each individual of species 2 than by each individual of species 1.
C. the population growth rate of species 2 is reduced equally by individuals of either species 1 or species 2.
D. we would also have to know the value of K2 to decide which of the above is true.
Question 3 of 20
Analysis of the Lotka-Volterra competition model implies that two competitors can coexist only when:
A. interspecific competition is stronger than intraspecific competition.
B. intraspecific competition is stronger than interspecific competition.
C. intraspecific and interspecific competition are equally strong.
D. predation or parasitism is stronger than interspecific competition.
Question 4 of 20
Two species occurring together in the same place are said to be:
Question 5 of 20
The __________ niche defines the physical conditions under which a species might live, in the absence of interaction with other species.
Question 6 of 20
The process of evolution toward niche divergence in the face of competition is called:
A. niche displacement.
B. niche evolution.
C. character displacement.
D. character evolution.
Question 7 of 20
A species feeding on the tissue of its host, while not killing it directly, is a:
Question 8 of 20
A “negatively phototaxic” amphipod will swim:
A. away from parasitic worms.
B. towards parasitic worms.
C. away from competing amphipods.
D. away from light.
Question 9 of 20
The presence of parasitic protozoa in a culture of competing Tribolium castaneum and T. confusum:
A. increases the likelihood of coexistence.
B. decreases the likelihood of coexistence.
C. has no effect on the outcome of competition.
D. can reverse the outcome of competition.
Question 10 of 20
The infestation of prickly pear cactus (Opuntia) in Australia was controlled by the release of a moth, Cactoblastis, which impacts cactus populations because it:
A. consumes cactus seeds.
B. consumes cactus pads.
C. introduces, as it attacks, fungi and bacteria that attack cactus pads.
D. both consumes cactus pads and introduces, as it attacks, fungi and bacteria that attack cactus pads.
Question 11 of 20
The standard error of the mean is equal to:
A. the sample variance divided by the sample size.
B. the sample variance divided by the square root of the sample size.
C. the sample standard deviation divided by the square root of the sample size.
D. twice the square root of the sample size.
Question 12 of 20
Gause’s experiments with Paramecium and Didinium showed:
A. extinction of the predator, followed by extinction of the prey, in all habitats.
B. coexistence of predator and prey with oscillating population sizes, but only in the presence of refuges and predator reservoirs.
C. coexistence of predator and prey, but with oscillating population sizes, in all habitats.
D. coexistence of predator and prey at fairly constant population sizes, but only in the presence of refuges and predator reservoirs.
Question 13 of 20
Periodical cicadas spend 13 or 17 years:
A. feeding in tree twigs before emerging as adults.
B. feeding on tree roots before emerging as adults.
C. as adults before laying eggs.
D. in a resistant, resting egg before hatching as larvae.
Question 14 of 20
Schistosoma flukes attack their human hosts when those humans:
A. consume infected freshwater snails.
B. consume infected fish.
C. consume plant tissue bearing spores.
D. bathe in water containing infective cercariae.
Question 15 of 20
Use of Procambarus crayfish to combat schistosomiasis in Africa:
A. is likely to be effective, and poses no important ecological risks.
B. is likely to be effective, but poses ecological risks because Procambarus is not native to Africa.
C. is unlikely to be effective, because the crayfish seem to eat infected snails only in the laboratory.
D. is unlikely to be effective, because the crayfish are just as suitable as hosts for the parasite as were the snails.
Question 16 of 20
An interaction between individuals of different species that benefit both partners is called:
Question 17 of 20
__________ mutualism describes a relationship where species are so dependent on their mutualistic relationship they cannot live in its absence.
Question 18 of 20
Mycorrhizal fungi (directly) help their plant partners acquire:
C. seed dispersal.
D. soil nutrients.
Question 19 of 20
Ant-acacia trees provide several services to their mutualistic ant partners. These include:
A. enlarged thorns to host ant colonies.
B. nectar from foliar nectaries.
C. nectar from floral nectaries.
D. both enlarged thorns to host ant colonies and nectar from foliar nectaries.
Question 20 of 20
The major benefit obtained by aspen sunflower, Helianthella quinquenervis, from its ant mutualists is:
A. improved attraction of pollinators.
B. reduced loss of leaf tissue to herbivorous insects.
C. more efficient extraction of soil nutrients.
D. reduced losses of seeds to seed predators.