Question 1

Cowbirds lay their eggs in the nests of smaller birds.The fast-developing cowbird chicks hatch first,and push the other baby chicks out of the nest as they hatch.Which interaction best describes cowbird behavior?
A) mutualism
B) parasitism
C) predation
D) exploitative competition

Accepted Answer

Cowbirds engage in parasitism as they benefit from using the smaller bird's nest to lay their eggs, but the smaller bird bears the costs of raising the cowbird chick at the expense of their own offspring. The cowbird chick eventually outcompetes and displaces the smaller bird's offspring, resulting in a net negative effect on the smaller bird's reproductive success.

Question 2

Which of the following is most likely to be an example of an induced response?
A) bright colors on the wings of a toxic butterfly
B) spines on a cactus habitually exposed to grazing
C) brightly colored flowers on a rosebush
D) color patterns on a poisonous snake

Accepted Answer

Induced responses are adaptations that are triggered by environmental stimuli. In the case of spines on a cactus, they are induced by the habitually exposure to grazing by animals. This adaptation helps the cactus to defend itself against herbivores. The other choices are examples of warning coloration or aposematism (A and D) and the attraction of pollinators (C), respectively.

Question 3

Flies belonging to the family Phoridae inject their eggs into fire ants.The larva that subsequently hatches feeds on the ant until it pupates.The larva would be best described as a
A) parasite.
B) gut mutualist.
C) predator.
D) pathogen.

Accepted Answer

The larva of the Phoridae fly is a parasite because it feeds on the fire ant host and ultimately harms or kills it as a result.

Question 4

Which of the following patterns represents the outcomes of a commensalistic relationship?
A) +/-
B) +/+
C) o/+
D) -/-

Accepted Answer

A commensalistic relationship is one in which one species benefits while the other remains unaffected. The symbol used to represent an unaffected species is "o", while the benefiting species is represented with a "+". Therefore, the pattern that represents commensalistic relationship is o/+.

Question 5

Which of the following patterns represents a competitive interaction?
A) +/-
B) +/+
C) o/+
D) -/-

Accepted Answer

The pattern -/- represents a competitive interaction because both organisms involved are negatively affected or harmed by the interaction. This type of interaction is characterized by a struggle for resources such as food, water, and shelter.

Question 6

The release of a parasitic wasp in California helped control the infestation of scale insects on citrus trees.However,it also caused the near extinction of a different species of parasitic wasp.Should we consider this experiment an unqualified success?
A) Yes; the scale insects are controlled, and the extinct wasp was not ecologically important.
B) Yes; as long as we get a result that helps humans, it does not matter what the effect is on other species.
C) No; the effect of the loss of the original species of wasp cannot be predicted and may be more significant than the benefits to the citrus tree crop.
D) No; the citrus tree population in California will now be able to rise to unmanageable numbers.

Accepted Answer

The impact of the loss of the original species of wasp cannot be predicted and may be significant. It is important to consider the impact on the ecosystem as a whole rather than solely focusing on the benefits to humans.

Question 7

In the centers of their ranges,two species of hummingbirds have very similar tongue lengths,but where the ranges overlap,one species has a shorter tongue and the other a longer tongue.This would most likely be an example of
A) seed-dispersal mutualism.
B) parasitism.
C) character displacement.
D) a predator-prey interaction.

Accepted Answer

This is an example of character displacement, where two species evolve to differ more in traits that overlap in their ranges, in order to reduce competition for resources such as nectar. In this case, the difference in tongue length would allow for each species to access different parts of a flower's nectar, reducing competition for that resource. The other options (seed-dispersal mutualism, parasitism, predator-prey interaction) do not accurately describe this scenario.

Question 8

Which of the following patterns represents the outcome of a parasitic relationship?
A) +/-
B) +/+
C) o/+
D) -/-

Accepted Answer

The answer of Which of the following patterns represents the...

Question 9

What statement summarizes the outcomes of a parasitic relationship?
A) Both the parasite and the host benefit.
B) Only the parasite benefits; the host is harmed.
C) Only the host benefits; the parasite is harmed.
D) Both the parasite and the host are harmed.

Accepted Answer

In a parasitic relationship, only the parasite benefits while the host is harmed.

Question 10

By growing on the trunk or branch of a tree,a lichen gains height and exposure to sunlight for photosynthesis.The tree is not harmed by the lichen but does not benefit either.The relationship between the lichen and the tree is
A) commensalism.
B) mutualism.
C) parasitism.
D) interference competition.

Accepted Answer

In commensalism, one organism benefits without harming or benefiting the other organism. In this case, the lichen benefits by gaining height and exposure to sunlight, but the tree is not harmed or benefited. Therefore, the relationship between the lichen and the tree is commensalism.

Question 11

Which of the following statements is FALSE?
A) The level of predation can be so intense that the prey can be driven to extinction.
B) Predation can stimulate the reproductive capacity of a prey species and can cause the abundance of that prey to increase.
C) The selective pressure caused by predation can alter the behavior of its prey.
D) The distribution of a predatory species can restrict the distribution of its prey.

Accepted Answer

Predation can stimulate the reproductive capacity of a prey species and cause the abundance of the prey population to increase is a true statement.

Question 12

Some species of warblers partition their niche by foraging in different parts of the same tree,although all birds eat the same species of insects and spiders.What mechanism has natural selection used to produce this interaction?
A) character displacement
B) behavioral modification
C) directional selection
D) competitive exclusion

Accepted Answer

Behavioral modification allows species to coexist by altering their behavior to reduce competition, such as foraging in different parts of the same tree.

Question 13

When two similar species inhabit the same area,they may evolve over time to become more different and
A) drive the other species to extinction.
B) reduce direct competition.
C) use up the other species' resources.
D) reduce their genetic variation.

Accepted Answer

When two similar species inhabit the same area, they may evolve over time to reduce competition by developing different traits or utilizing different resources. This is known as resource partitioning and helps both species coexist without one outcompeting the other or causing extinction. Therefore, option B is the best choice.

Question 14

Parasites,and the disease they cause,represent a distinctive type of exploitation because
A) of the high mortality rates associated with infection.
B) parasites affect only specific portions of the host.
C) of the chronic and progressive debilitation of the host.
D) parasites represent the only species interaction where the symbiont lives on or in the host organism.

Accepted Answer

Parasites often cause chronic and progressive debilitation, weakening the host over time rather than causing immediate death, which is a distinctive feature of parasitic exploitation.

Question 15

A praying mantis captures and devours many insects during its lifetime; the relationship between a mantis and the exploited species (for example,a grasshopper)is one of
A) parasite/host.
B) pathogen/prey.
C) parasite/prey.
D) predator/prey.

Accepted Answer

A praying mantis is a predator that captures and devours other insects, such as grasshoppers. The relationship between the mantis and its prey is one of predator/prey.

Question 16

Female ducks frequently deposit fertile eggs in the nests of unattended neighboring ducks.These eggs hatch and are then reared by the foster parent.What term best describes this behavior?
A) parasitism
B) behavioral mutualism
C) exploitative competition
D) nest mutualism

Accepted Answer

This behavior is best described as parasitism because the female duck is benefiting by having her eggs incubated and her offspring raised by another duck, often at a cost to the foster parent who invests resources in raising offspring that are not her own.

Question 17

In ________ competition,species compete indirectly for a shared resource,each reducing the amount available to the other competitor.
A) exploitative
B) restrictive
C) interference
D) advantageous

Accepted Answer

In exploitative competition, species compete indirectly by consuming a shared resource, thus reducing its availability for others.

Question 18

Herbivores interact exploitatively with the plants they consume; do they simultaneously participate in any other relationships within their communities?
A) Yes: an herbivore will have mutualistic relationships with intestinal bacteria and an exploitative relationship with its predators.
B) No: community relationships always have costs, so reducing them increases an organism's fitness.
C) No: only a single type of interaction can occur at a time, although herbivores can participate in several exploitative relationships at once.
D) Yes: each of the plant species eaten needs to be considered a separate interaction.

Accepted Answer

Herbivores can have mutualistic relationships with their intestinal bacteria, which help digest tough plant material. They also have exploitative relationships with their predators, who consume them. Therefore, option A is the correct answer. Option B is incorrect because reducing community relationships may not always increase an organism's fitness. Option C is incorrect because multiple interactions can occur at the same time. Option D is incorrect because each plant species eaten is not necessarily a separate interaction.

Question 19

Which of the following statements about competition is FALSE?
A) It can limit the distribution of a species.
B) It can limit the abundance of a species.
C) It can increase the differences between species.
D) It can make two species become more alike.

Accepted Answer

Competition typically leads to differentiation and divergence between species as they evolve to specialize and occupy different niches to reduce competition. It does not typically lead to species becoming more alike.

Question 20

Examine the following graph; what best describes the cycling that each population experiences? 
A) Lynx populations decrease in size when hare populations increase in size; hares are the superior competitors.
B) Lynx populations increase in size when hare populations decrease in size; lynx are the superior competitors.
C) Lynx populations decrease in size when hare populations decrease in size; lynx are exploiting the hare population.
D) The increase and decrease of each species is driven by oscillating density-independent factors, but since they share the same habitat, the cycles coincide.

Accepted Answer

The graph shows that as hare populations decrease, lynx populations increase, and vice versa. This suggests a predator-prey relationship between the two species, where the lynx are the superior competitors as they are able to thrive when the hare populations are low.

Quiz 23: Ecological Communities

Cowbirds lay their eggs in the nests of smaller birds.The fast-developing cowbird chicks hatch first,and push the other baby chicks out of the nest as they hatch.Which interaction best describes cowbird behavior?

Which of the following is most likely to be an example of an induced response?

Flies belonging to the family Phoridae inject their eggs into fire ants.The larva that subsequently hatches feeds on the ant until it pupates.The larva would be best described as a

Which of the following patterns represents the outcomes of a commensalistic relationship?

Which of the following patterns represents a competitive interaction?

The release of a parasitic wasp in California helped control the infestation of scale insects on citrus trees.However,it also caused the near extinction of a different species of parasitic wasp.Should we consider this experiment an unqualified success?

In the centers of their ranges,two species of hummingbirds have very similar tongue lengths,but where the ranges overlap,one species has a shorter tongue and the other a longer tongue.This would most likely be an example of

Which of the following patterns represents the outcome of a parasitic relationship?

What statement summarizes the outcomes of a parasitic relationship?

By growing on the trunk or branch of a tree,a lichen gains height and exposure to sunlight for photosynthesis.The tree is not harmed by the lichen but does not benefit either.The relationship between the lichen and the tree is

Which of the following statements is FALSE?

Some species of warblers partition their niche by foraging in different parts of the same tree,although all birds eat the same species of insects and spiders.What mechanism has natural selection used to produce this interaction?

When two similar species inhabit the same area,they may evolve over time to become more different and

Parasites,and the disease they cause,represent a distinctive type of exploitation because

A praying mantis captures and devours many insects during its lifetime; the relationship between a mantis and the exploited species (for example,a grasshopper) is one of

Female ducks frequently deposit fertile eggs in the nests of unattended neighboring ducks.These eggs hatch and are then reared by the foster parent.What term best describes this behavior?

In ________ competition,species compete indirectly for a shared resource,each reducing the amount available to the other competitor.

Herbivores interact exploitatively with the plants they consume; do they simultaneously participate in any other relationships within their communities?

Which of the following statements about competition is FALSE?

Examine the following graph; what best describes the cycling that each population experiences?