Question 1

Insects and tadpoles of Fowler's toad were allowed to compete at natural densities with tadpoles of the Pine Barrens tree frog.The intensity of competition was similar for both insects and Fowler's toad.What does this tell you about competition between unrelated species?
A) It may seem that more closely related species should have a greater intensity of competition, but interspecific competition can occur across diverse taxa at similar intensities.
B) That more closely related species should outcompete less closely related species because intraspecific competition is greater than interspecific competition.
C) Intraspecific competition can occur across diverse taxa at similar intensities.
D) It may seem that more closely related species should have a lesser intensity of competition, but intraspecific competition can occur across diverse taxa at similar intensities.

Accepted Answer

The fact that the intensity of competition was similar for both insects and the Fowler's toad, despite being unrelated species, suggests that competition can occur across diverse taxa at similar intensities. This contradicts the idea that more closely related species should have a greater intensity of competition, as suggested in option B. Option C is not a correct explanation for the scenario described, as there is no mention of intraspecific competition. Option D also does not explain the observed pattern of competition between unrelated species in this scenario.

Question 2

A DNA analysis of ectomycorrhizal species inhabiting the floor of a pine forest shows that species are restricted to distinct layers of the leaf litter.Based on the example in the textbook,this is most likely due to
A) Coexistence of the ectomycorrhizal species.
B) Interspecific competition.
C) Differential resource utilization.
D) Niche differentiation.

Accepted Answer

Differential resource utilization refers to the ability of different species to exploit different resources or the same resource in different ways, allowing them to coexist in the same environment. In this case, the ectomycorrhizal species are likely utilizing different layers of leaf litter as distinct resources.

Question 3

To minimize or avoid competition,coexisting species,with an apparent potential to compete,will exhibit differences in which of the following?
A) Morphology.
B) Physiology.
C) Geographic distribution
D) Morphology

Accepted Answer

The answer of To minimize or avoid competition,coexisting species,with an...

Question 4

The breeding sites of Virginia's warbler and orange-crowned warblers overlap in central Arizona.When one species was experimentally removed,the remaining species fledged greater percentages of young per nest.The experimental removal of one species indicates that
A) There is intraspecific competition.
B) There is differential resource utilization.
C) There is interspecific competition.
D) The two species occupy different niches.

Accepted Answer

The experimental removal of one species and the resulting increase in productivity of the other species suggests that the two species were in competition for resources. This is an example of interspecific competition, where two different species compete for the same resources in the same habitat. The other options, like intraspecific competition, differential resource utilization, or niche differentiation, do not explain the observed result of the experiment.

Question 5

When considering what the Competitive Exclusion Principle states,what should one remember?
A) All species have their own niche.
B) Niche differentiation does not indicate that there are coexisting competitors.
C) The species may not be competing at all and may never have done so in their evolutionary past.
D) There must be some data to support the idea of interspecific competition.

Accepted Answer

The answer of When considering what the Competitive Exclusion Principle...

Question 6

You determine that two species of birds coexist in the same tree,but that they have different feeding behaviors that prevents them from competing with one another for resources.One bird species feeds on insects found in the bark of this tree,while the other bird species feeds on insects at the branch tips.One explanation of your observation could be that:
A) Coexistence is due to niche differentiation.
B) Coexistence is due to shared resource utilization.
C) Coexistence is not due to resource specialization.
D) None of the above.

Accepted Answer

The fact that the two bird species have different feeding behaviors indicates that they have different niches or roles within the same tree. This is an example of niche differentiation, which allows species to coexist without competing directly for resources.

Question 7

Several species of anemone fish are associated with a particular species of anemone.Each species shows a characteristic preference for a particular zone.However,when anemone fish are associated with the same anemone,they are typically found in different zones.This is an example of
A) Niche differentiation.
B) Intraspecific competition.
C) Coexistence.
D) Niche complementarity.

Accepted Answer

The answer of Several species of anemone fish are associated...

Question 8

Replicates of seed mixtures containing four species are sown at a high density.However,the seeds are sown two ways.One way,they are sown at random.The other way they are sown as single-species aggregations.If the results showed that the performance of the superior competitor of the four species was compromised when grown as an aggregation but that aggregation improved the performance of the three inferior competitors,what would you think?
A) Intraspecific competition was not strong and coexistence is not favored.
B) Interspecific and intraspecific competition did not matter because niche differentiation was more important.
C) Coexistence was favored by niche differentiation.
D) When planted as aggregations, this ensured that intraspecific competition was stronger than interspecific competition.

Accepted Answer

The performance of the superior competitor was compromised when grown as an aggregation, indicating that intraspecific competition (competition within the same species) was strong in this scenario. Conversely, the improved performance of the three inferior competitors when grown as aggregations suggests that being in groups helped them face the interspecific competition (competition between different species) better. This implies that intraspecific competition was indeed stronger than interspecific competition when the species were planted as aggregations.

Question 9

The gecko,Lepidodactylus lugubris is outcompeted by an introduced species of gecko,Hemidactylus frenatus.This is because
A) Both species are insectivorous, and insects are a limiting resource.
B) Lepidodactylus lugubris is cannibalistic, and as a result depletes its own populations.
C) The diets of the two species overlap substantially.
D) Hemidactylus frenatus depletes resources to lower levels than L. lugubris.

Accepted Answer

The answer of The gecko,Lepidodactylus lugubris is outcompeted by an...

Question 10

If a species is a weak competitor relative to another species that is a superior competitor,the weak competitor may be able to persist if:
A) It is a good colonizer and the environment homogenous.
B) It is a good colonizer and the environment is heterogeneous.
C) Only the environment needs to be heterogeneous.
D) The species needs only to be a good colonizer.

Accepted Answer

The weak competitor may be able to persist if it is a good colonizer and the environment is heterogeneous. A heterogeneous environment would provide niches for the weaker competitor to exploit, while their ability to colonize would allow them to find and occupy these niches. Additionally, the heterogeneity of the environment would prevent the superior competitor from monopolizing all resources.

Question 11

Niche differentiation can be the result of:
A) Species evolving separately with distinct niches. They were never competitors, nor are they now.
B) The species are competitors now.
C) The species were competitors in the past, but do not compete now.
D) Competition in the past eliminated other species and now only those species with different niches exist.

Accepted Answer

The answer of Niche differentiation can be the result of:
A)...

Question 12

Negatively associated distributions
A) Occur within a community.
B) There are no potential competitors without niche differentiation.
C) There are potential competitors without niche differentiation .
D) Competitors occur only where the other is absent.

Accepted Answer

The answer of Negatively associated distributions
A) Occur within a community.
B)...

Question 13

Competing species can coexist when both species are provided with a i)realized niche,ii)fundamental niche,iii)guild,iv)competitor,v)overlap in resource utilization
A) ii.
B) i, ii, iii, v.
C) i.
D) ii, iv, v.

Accepted Answer

Competing species can coexist when both species are provided with a realized niche, which is the actual conditions and resources in which a species exists due to competition.

Question 14

Four species of ants that coexist in Kenya all occupy Acacia trees.Species battle for the occupation of trees and must colonize or recolonize sites as they become available.How is it possible that these four species overlap?
A) There is environmental heterogeneity.
B) They do not overlap. Each has its own niche.
C) Most effective colonizers are poor competitors.
D) Most effective competitors are poor colonizers.

Accepted Answer

The answer of Four species of ants that coexist in...

Question 15

Four warbler species co-occur on the Mediterranean islands of Sardinia and Corsica.The four species' diets overlap,they each look similar,and they all utilize similar habitat.Upon closer investigation it appears that each species differentially uses zones within the habitat to forage.These species
A) Are interspecific competitors
B) Could be interspecific competitors, but one needs experimental evidence to know if they are in fact competitors.
C) Are not examples of niche differentiation.
D) Are not examples of differential resource utilization.

Accepted Answer

The fact that the four species have overlapping diets and utilize similar habitats suggests that they could be competitors. However, without experimental evidence, it cannot be confirmed whether they are actually competing or undergoing niche differentiation through differential resource utilization.

Question 16

Fires in the Mojave Dessert are occurring more frequently because of the introduction of nonnative grasses that have become invasive.How are these grasses able to persist?
A) The grasses are able to outcompete native plants for space.
B) The grasses are able to grow back faster than native plants.
C) The grasses do not persist, and instead die after a fire.
D) The grasses have evolved fire resistance and they don't burn.

Accepted Answer

Nonnative grasses in the Mojave Desert are able to persist because they can outcompete native plants for space (A) and they can grow back faster than native plants after a fire (B), which allows them to dominate the landscape and contribute to more frequent fires.

Question 17

The diatom Asterinonella excludes the diatom Cyclotella in laboratory experimental cultures when phosphate concentrations are low.But,Cyclotella excludes Asterionella when silicate supplies are low.However,when there are balanced supplies of silicate and phosphorus,the two diatoms coexist.This is explained by
A) There being a fundamental niche for both species when each is provided sufficient concentrations of a resource on which they are inferior.
B) There being niche complementarity for both species when each is provided an abundance of a resource.
C) There being no fundamental or realized niche for either species.
D) There being a realized niche for both species when each is provided sufficient concentrations of a resource on which they are inferior.

Accepted Answer

When each species is provided with sufficient concentrations of the resource they are inferior in, they can coexist, indicating a realized niche for both species.

Question 18

Which of the following are correct: A neutral model predicts that a community structured by interspecific competition should look like: i)potential competitors that coexist in a community should exhibit niche differentiation; ii)this niche differentiation will often manifest itself as morphological differentiation,iii)a community of species will tend to vary along one niche,iv)within a community,potential competitors with little or no niche differentiation should not coexist,so each should tend to occur only where the other is absent
A) ii, iii.
B) i.
C) i, iii.
D) ii, iv.

Accepted Answer

The answer of Which of the following are correct: A...

Question 19

You observe ten species of trees in a rainforest.You learn that species with similar light requirements tend to differ in terms of preferred soil textures and vice versa.You should recognize this pattern as
A) Niche complementarity.
B) Intraspecific competition.
C) Interspecific competition.
D) Niche differentiation.

Accepted Answer

The answer of You observe ten species of trees in...

Question 20

Competing species often coexist at one spatial scale but are found to have distinct distributions at a finer scale of resolution.The Dolly Varden charr and the white-spotted charr are competing species.These two fish species coexist in the same stream,but at a finer scale
A) Each is confined to its own zone due to morphology.
B) They actually compete in sympatry.
C) Both are aggressive but white-spotted charr are more aggressive and Dolly Varden charr avoid them.
D) Each is confined to its own zone due to temperature-mediated competition.

Accepted Answer

Temperature-mediated competition can lead to distinct distributions at a finer scale, as different species may have different temperature preferences or tolerances, leading to spatial segregation within the same habitat.

Quiz 6: Interspecific Competition

Insects and tadpoles of Fowler's toad were allowed to compete at natural densities with tadpoles of the Pine Barrens tree frog.The intensity of competition was similar for both insects and Fowler's toad.What does this tell you about competition between unrelated species?

A DNA analysis of ectomycorrhizal species inhabiting the floor of a pine forest shows that species are restricted to distinct layers of the leaf litter.Based on the example in the textbook,this is most likely due to

To minimize or avoid competition,coexisting species,with an apparent potential to compete,will exhibit differences in which of the following?

The breeding sites of Virginia's warbler and orange-crowned warblers overlap in central Arizona.When one species was experimentally removed,the remaining species fledged greater percentages of young per nest.The experimental removal of one species indicates that

When considering what the Competitive Exclusion Principle states,what should one remember?

Several species of anemone fish are associated with a particular species of anemone.Each species shows a characteristic preference for a particular zone.However,when anemone fish are associated with the same anemone,they are typically found in different zones.This is an example of

The gecko,Lepidodactylus lugubris is outcompeted by an introduced species of gecko,Hemidactylus frenatus.This is because

If a species is a weak competitor relative to another species that is a superior competitor,the weak competitor may be able to persist if:

Niche differentiation can be the result of:

Negatively associated distributions

Competing species can coexist when both species are provided with a i) realized niche,ii) fundamental niche,iii) guild,iv) competitor,v) overlap in resource utilization

Four species of ants that coexist in Kenya all occupy Acacia trees.Species battle for the occupation of trees and must colonize or recolonize sites as they become available.How is it possible that these four species overlap?

Four warbler species co-occur on the Mediterranean islands of Sardinia and Corsica.The four species' diets overlap,they each look similar,and they all utilize similar habitat.Upon closer investigation it appears that each species differentially uses zones within the habitat to forage.These species

Fires in the Mojave Dessert are occurring more frequently because of the introduction of nonnative grasses that have become invasive.How are these grasses able to persist?

You observe ten species of trees in a rainforest.You learn that species with similar light requirements tend to differ in terms of preferred soil textures and vice versa.You should recognize this pattern as

Competing species often coexist at one spatial scale but are found to have distinct distributions at a finer scale of resolution.The Dolly Varden charr and the white-spotted charr are competing species.These two fish species coexist in the same stream,but at a finer scale