Deck 6: Interspecific Competition

Question 1

What does the Competitive Exclusion Principle state?

A) The Competitive Exclusion Principle states that if two competing species coexist in a stable environment, then they do so as a result of differentiation of their realized niches.
B) The Competitive Exclusion Principle states that all species within a community coexist in an unstable environment, and that they are structured by competition that leads to realized niches.
C) The Competitive Exclusion Principle states that if a guild of competing species coexist in an stable environment, they do so as a result of differentiation of their fundamental niche.
D) None of the above

Answer 1

A

Question 2

The textbook states that determining the effects of interspecific competition can be very difficult to do,especially when it seems as if two species competitively coexist.Which of the following types of experiments would most likely allow you to confirm and determine the effects of interspecific competition between two closely related species in nature?

A) Removal study
B) Reciprocal transplant study
C) Laboratory observation study or a "glass bottle study"
D) Ecological survey study

Answer 2

A

Question 3

Why is it impossible to "prove" an evolutionary effect of interspecific competition?

A) Because you cannot directly observe evolution that has already occurred.
B) Because you cannot directly test interspecific competition.
C) Because you cannot control experiments for competition.
D) All of the above.

Answer 3

A

Question 4

Let us assume there are two species of parasitoid wasps and you are interested in understanding how inter- and intra- specific competition affect each species reproductive output.Using the Lotka-Volterra model,the competitive effects of these two wasps species is best described by the following equations,K₂ ?_{12 > K1 and K1?12 > K2.What would this mean?}

A) The competitive effect of species 2 is greater upon individuals of its own species. This would likely occur because intraspecific competitive effects are greater than interspecific competitive effects.
B) Interspecific competition is balancing population sizes.
C) The competitive effect of both species is greater upon individuals of the other species than on their own species. This would likely occur when interspecific competition is greater than intraspecific competition.
D) The competitive effect of species 1 is greater upon individuals of its own species. This would likely occur because intraspecific competitive effects are greater than interspecific competitive effects.

Question 5

Coexistence between a superior and inferior competitor can occur if

A) The two species have independent, aggregated distributions.
B) The superior is homogenous throughout the habitat.
C) Competition were directed most from the superior to the inferior competitor.
D) All of the above.

Question 6

Niche complementarity requires

A) There be a community of species in several niche dimensions, and that a species occupying a similar position along one dimension will not tend to differ along another dimension.
B) There be a community of species in several niche dimensions, and that a species occupying a similar position along one dimension will tend to differ along another dimension.
C) That a species occupying a similar position along one dimension will not tend to differ along another dimension.
D) There to be an isolated species that occupies a position along one niche dimension, but never differs along another dimension.

Question 7

According to the text,which of the following predictions of a community structured by interspecific competition has not been tested using the null model analysis approach?

A) Potential competitors coexisting in a community should have differentiated niches
B) Potential competitors in a community with little or no niche differentiation should have negatively associated distributions
C) Potential competitors who coexist do so often due to morphological differentiation of their niches
D) Answers a, b, and c

Question 8

What does the theory of the "Ghost of Competition Past" state?

A) The theory explains how coexisting species, with no apparent potential to compete, will exhibit differences in behavior, physiology, or morphology to ensure that they compete as much as possible.
B) The theory explains how coexisting species, with an apparent potential to compete, will exhibit differences in behavior, physiology, or morphology to ensure that they compete as much as possible.
C) The theory explains how coexisting species, with an apparent potential to compete, will exhibit differences in behavior, physiology, or morphology to ensure that they compete as little as possible.
D) None of the above

Question 9

For any given species,there is a _______,which describes the niche that occurs under normal circumstances of interspecific competition within a community and typically differs from the hypothetical ______,which describes the niche that the species would inhabit if interspecific competition was removed.

A) Realized niche, fundamental niche
B) Realized niche, ecological niche
C) Community niche, ecological niche
D) Fundamental niche, realized niche

Question 10

The fundamental niche is

A) The realized niche because it is all the resources and conditions that a species needs to coexist within its community
B) The combination of conditions and resources that allows a species to exist, when considered in isolation from other, harmful species.
C) The combination of resources that a species needs to survive.
D) Habitat that is required by a species.

Question 11

The Lotka-Volterra Model relies heavily on a variable known as the competitive coefficient (?12).Which of the following statements regarding the competitive coefficient is true?

A) The value of the competitive coefficient is constant for a given species, regardless of competitor it is being compared to
B) If the value of ?12 = 0.5 for any species 1 and species 2, then the competitive effect that species 2 has on species 1 is twice the effect species 1 has intraspecifically
C) If the value of ?12 = 0.5 for any species 1 and species 2, then the competitive effect that species 2 has on species 1 is half the effect species 1 has intraspecifically
D) If the value of ?12 = 0.5 for any species 1 and species 2, then the competitive effect that species 1 has on species 2 is half the effect species 2 has intraspecifically

Question 12

The Competitive Exclusion Principle allows researchers to assume

A) That coexistence occurs because species have competed and formed different niches.
B) There is no need for proof of interspecific competition.
C) The species are still competing and always will until niche differentiation occurs.
D) None of the above.

Question 13

Woodpeckers are known for their conspicuously loud pecking of trees,which is a necessary foraging behavior.Unlike many other birds,nearly all woodpeckers use the same foraging technique of pecking into the trunk of a tree to acquire food (often insects that inhabit the tree).Although woodpeckers use the same foraging technique,certain species prefer to forage at different heights in the same species of tree based on the size of the woodpecker species.Which of the following ecological terms best describes this practice?

A) Fundamental niche
B) Realized niche
C) Niche complementarity
D) Niche differentiation

Question 14

The Competitive Exclusion Principle states that

A) If two competing species coexist in a stable environment, then they do so as a result of niche complementarity.
B) If two competing species coexist in a stable environment, then they do so as a result of niche differentiation.
C) If two competing species coexist in an unstable environment, then they do so as a result of niche complementarity.
D) If two competing species coexist in an unstable environment, then they do so as a result of niche differentiation.

Question 15

You are on an island and observe that an introduced species of mongoose differs significantly in size from its mainland counterpart.The introduction to the island occurred within 100-200 generations.Based on your reading in Chapter 6,what is one reason why this mongoose may have increased in size?

A) There are fewer resources on the island.
B) It is due to the Ghost of Competition Past.
C) The available prey on this island is larger then prey on the mainland.
D) A larger mongoose species that is native to its range is not present on the island.

Question 16

Which of the following is a common misconception regarding the Competitive Exclusion Principle?

A) It does not conflict with Gause's Principle
B) Species that coexist in different ecological niches necessarily are coexisting competitors due to their different niches.
C) Competing species that coexist must be subject to constant ecological conditions to be considered an example of the competitive exclusion principle
D) Species that adhere to the competitive exclusion principle and coexist do so as a result of different realized niches

Question 17

In the Lotka-Volterra Model,there are numerous factors that determine the populations of the two competing species.If we were to graph the zero isoclines of two competing species,such as the baboon and cheetah,then we can learn how each population's size will be affected under certain ecological circumstances.Using the notation for the model from the text,what would happen to the population of baboons (species 1)and cheetahs (species 2)if K2 > K1 ?21 and K2 ?12

A) Baboons would go extinct and cheetahs would reach their carrying capacity
B) Cheetahs would go extinct and baboons would reach their carrying capacity
C) Cheetahs and baboons would reach stable equilibrium populations and competitively coexist
D) Both answers a and b are possible, but it is not possible to determine which without more data

Question 18

Which is an example of niche complementarity?

A) Species of anemone fish associated with the same anemone tending to be found in different shore zones, while anemone fish living in the same zone tend to be associated with different anemone species.
B) Two species of phytoplankton that coexist when resources are balanced.
C) Three mongoose species that overlap and develop morphological variation in response to selection for smaller prey.
D) All of the above

Question 19

The Dolly Varden char is found at higher altitudes than another fish species,the white-spotted char.One reason this occurs is because

A) Dolly Varden char cannot occupy the habitat where white-spotted char live even when there are no white-spotted char there.
B) Dolly Varden char could outcompete white-spotted char and they actually are found in lower altitude zones where white-spotted char live.
C) The boundary is due to temperature-mediated competition that favors white-spotted char.
D) The boundary is due to behavioral and morphological-mediated competition that favors white-spotted char.

Question 20

Which of the following is an aspect of a species that would not show evolutionary evidence of past interspecific competition with another species?

A) Species behavior
B) Species morphology
C) Species niche
D) None of the above

Question 21

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.

Question 22

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.

Question 23

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.

Question 24

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.

Question 25

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.

Question 26

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.

Question 27

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.

Question 28

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.

Question 29

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.

Question 30

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.

Question 31

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.

Question 32

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.

Question 33

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.

Question 34

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.

Question 35

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.

Question 36

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.

Question 37

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.

Question 38

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.

Question 39

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.

Question 40

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.

Question 41

Species are often excluded from habitat in which they could exist perfectly well in the absence of interspecific competition.As an example,Dolly Varden charr can live in the white-spotted charr zone,but only when

A) That zone is highly populated with white-spotted charr.
B) There are no white-spotted charr present.
C) The two species are found together, the water temperature is higher than usual, and Dolly Varden charr become more aggressive to individuals of its own species.
D) None of the above.

Question 42

Some ant species from Africa were best at competing for space,but were worst at colonizing.This is an example of ________

A) Coexistence.
B) Interspecific competition.
C) Niche differentiation.
D) A trade-off.

Question 43

______is when individuals of one species suffer a reduction in fecundity,survivorship,or growth as a result of exploitation or resources or interference by individuals of another species.

A) Intraspecific competition.
B) Interference competition.
C) Interspecific competition.
D) Guild competition.

Question 44

Species competing but coexisting by utilizing slightly different resources is thought of as ______

A) Differential resource utilization.
B) A realized niche.
C) A fundamental niche.
D) Niche complementarity.

Question 45

Null models seek to compare real communities to "neutral" or null communities by omitting _____ ?

A) Intraspecific competition.
B) Interspecific competition.
C) Interspecific and intraspecific competition.
D) None of the above.

Question 46

Under variable conditions,competition may only rarely "run its course," and the outcome cannot be predicted simply by _________.

A) Application of environmental heterogeneity.
B) saying it's due to the Competitive Exclusion Principle.
C) Interspecific competition.
D) None of the above.

Question 47

A group of species that exploit the same class of environmental resources in the same way is called a _____.

A) Tribe.
B) Niche.
C) Guild.
D) Interspecific.

Question 48

Species living in _____ live in the same place.

A) Allopatry.
B) Sympatry.
C) Pleiotropy.
D) Differentiated niches.

Question 49

At a spatial scale of approximately 10mm in radius,the grass species Aira praecox was found to be _______ with another grass,Erodium cicutarium.As a result A.praecox tended to occur in small single-species clumps making it less likely to experience competition from E.cicutarium.

A) Positively associated.
B) Negatively associated.
C) Neutrally associated.
D) Slightly associated.

Question 50

______ is the combination of conditions and resources that allow that species to exist,grow,and reproduce in the presence of specified other species that might be harmful to its existence.

A) A fundamental niche.
B) A realized niche.
C) Niche differentiation.
D) Niche complementarity.