Ecology Exam 2 12-15
The transmission coefficient of the hypothetical disease Dirks fever is 0.8. If the combined death and recovery rate is 0.4, what is the threshold density for Dirks fever?
0.5
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 _____. a) crypsis b) an induced defense c) aposematic coloration d) silencing
A
Which of the following is true if competition is occurring between species 1 and species 2, and α = 5? a) Each individual of species 2 decreases the growth of species 1 by the same amount as would five individuals of species 1. b) Each individual of species 1 decreases the growth of species 2 by the same amount as would five individuals of species 2. c) Each individual of species 1 decreases the growth of species 1 by the same amount as would five individuals of species 2. d) Each individual of species 2 decreases the growth of species 1 by the same amount as would five individuals of species 2.
A
Which of the following would most likely contribute to the long-term persistence of a fugitive species? a) Periodic disturbances b) Apparent competition c) Competitive exclusion d) Character displacement
A
A student is asked to determine which species of green crab they have found based on the predator avoidance response index. After three independent trials, the average predator avoidance response index was determined to be 12. Which species has the student been studying? a) Gibbula cineraria b) Littorina littorea c) Gibbula umbilicalis d) Osilinus lineatus
A
An ant colony maintains and farms a species of fungus on which it feeds. The fungus, in turn, is parasitized by a bacterium. The ant/fungus interaction is _______ and the fungus/bacterium is _______. a) +/+; +/- b) +/0; +/- c) +/+; +/0 d) +/0; +/+
A
Ants form mutualisms with treehoppers. Which is true about this interaction? a) Ants protect treehoppers from predators. b) Treehoppers protect ants from predators. c) Treehoppers modulate their secretion of honeydew when predators are low. d) Ants modulate treehopper honeydew secretions when predators are low.
A
Competition is a) often asymmetrical. b) often symmetrical. c) common but not ubiquitous. d) uncommon and ubiquitous.
A
Exploitation competition occurs in which of the following situations? a) When species share the same limited resource, thus negatively affecting one another indirectly b) When species share the same limited resource, thus negatively affecting one another directly c) When species thwart each other from using the same limited resource, thus negatively affecting one another directly d) When species thwart each other from using the same limited resource, thus negatively affecting one another indirectly
A
Herbivores can overcome plant defenses in which of the following ways? a) Evolve digestive enzymes to tolerate plant chemical defense b) Evolve behaviors that strengthen plant defenses c) Evolve toxins that kill the plant d) Both b and c
A
How can a facilitator increase species richness in communities? a) A facilitator can benefit a dominant species that, in turn, benefits other species. b) A facilitator can directly compete with other species. c) A facilitator can benefit a dominant species that, in turn, negatively affects other species. d) A facilitator can compete with another facilitator species that, in turn, negatively affects other species.
A
How can parasites or pathogens affect species interactions? a) A host may become more susceptible to predation. b) A host may be better able to catch its prey. c) A host may be a better competitor. d) Both a and c
A
How could you increase the number of plant species in a prairie community dominated by one grass species competitor? a) Periodically mow the prairie to disturb the grass species. b) Periodically mow the prairie to disturb the other plant species. c) Remove an herbivore grazer that prefers the grass species. d) Remove a competitor species that limits the grass species.
A
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) a decrease; a decrease b) an increase; a decrease c) an increase; no change d) no change; no change
A
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 a) below 50. b) equal to 50. c) above 50. d) between 50 and 100.
A
The Anopheles mosquito, which causes malaria, requires warm temperatures to complete the life cycle of Plasmodium falciparum. Which of the following statements is true? a) If temperatures increase due to climate change, it is hypothesized that the incidences of malaria in humans and wildlife will increase. b) If temperatures decrease due to climate change, it is hypothesized that the incidences of malaria in humans and wildlife will increase. c) If temperatures decrease due to climate change, it is hypothesized that the incidences of malaria in humans and wildlife will increase. d) If temperatures decrease due to climate change, it is hypothesized that the incidences of malaria will shift toward the poles.
A
The RNE (relative neighbor effect) measures growth of a target plant species in the presence and absence of neighboring species. The figure shows graphs of the RNE at eleven sites around the world. RNE was measured at high and at low elevations at each site. RNE values above zero (blue) indicate that neighboring plants increased the growth of target species; RNE values below zero (red) indicate that neighbors decreased target species growth. This study showed that the presence of neighboring plants most often benefited the target plants at _____. a) high-elevation sites b) low-elevation sites c) sites in North America only d) sites in Europe only
A
Which is a mechanism that hosts do not use to defend themselves against parasites? a) Resembling a palatable host b) Immune system c) Symbiont defense d) Biochemical defenses
A
A population at the zero population growth isocline is _____. a) increasing in size via exponential growth b) stable in size c) decreasing in size d) increasing in size via logistic growth
B
What does the Lotka-Volterra predator-prey model suggest about trophic interactions? a) Predator and prey populations cycle when the abundance of one population is not dependent on the abundance of the other population. b) Predator and prey populations cycle when the abundance of one population is dependent on the abundance of the other population. c) Predator and prey populations cycle when the predator and prey isoclines intersect. d) Predator and prey populations cycle when the predator and prey isoclines intersect.
B
What is an advantage of endoparasitism? a) Exposure to the external environment b) Avoidance of natural enemies c) Dispersal from one host individual to another d) Exposure to the host's immune system
B
What is the difference between mutualism and commensalism? a) Mutualism is a mutually beneficial interaction whereas commensalism is an interaction in which one species benefits and the other species may be harmed. b) Mutualism is a mutually beneficial interaction whereas commensalism is an interaction in which one species benefits and the other species does not benefit and is not harmed. c) Mutualisms are symbiotic whereas commensalisms are non-symbiotic. d) None of the above
B
When can competition become intense? a) When an unshared limited resource becomes scarce b) When a shared limited resource becomes scarce c) When one species eats another species d) When one species makes a limited resource more abundant
B
Which of the following should reduce the critical threshold for the spread of disease? a) Decreasing the transmission of coefficient b) Increasing the rate at which individuals die c) Decreasing the rate at which individuals become immune d) Increasing the density of susceptible individuals
B
Why do some carnivores engage in prey switching? a) Given that they are specialists, they will switch to the least available prey. b) Given that they are generalists, they will switch to the most available prey. c) Given that they are generalists, they will forage on all available prey. d) Given that they are specialists, they will switch to the most available prey.
B
How can humans overcome the malaria parasite? a) Encapsulation of the Plasmodium virus b) Inject Plasmodium with virus-like particles c) The spleen destroys red blood cells that contain Plasmodium d) Red blood cells divide rapidly to starve the Plasmodium
C
Which example from the chapter shows how predators act through direct means to alter communities? a) Sea stars and mussels b) Golden apple snails and wetland plants c) Geese feeding on marsh plants after the 1970s d) Foxes feeding on seabirds
C
All other factors being equal, which scenario is least likely to involve coevolution? a) An obligate positive interaction in which one party lives inside the other b) An obligate positive interaction in which the two parties benefit each other c) An obligate positive interaction in which one party consume the other d) A facultative interaction in which the two parties are from different kingdoms
D
Character displacement is likely to _______ the competition coefficients in two competing species and to _______ resource partitioning. a) increase; increase b) lower; increase c) lower; eliminate d) increase; lower
B
How do predation and herbivory differ from parasitism and parasitoidism? a) Parasitism and parasitoidism are not exploitative relationships. b) Most parasites and parasitoids spend their entire lives consuming a single individual, whereas herbivores and predators usually eat at least several different individuals. c) Unlike parasitoids and parasites, predators and herbivores usually do not exert strong selective pressures on their food organisms. d) Parasitism never results in the death of the organism, while predation and herbivory usually do cause the death of the organisms they eat.
B
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? a) Whether natural selection was operating to influence the population cycles b) The complexity of the habitat c) The nature of the prey's stress response d) Whether the predators were "sit-and-wait" or active
B
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? a) Larynx can move great distances. b) Only some, but not all, predators were excluded in the treatment. c) Excess food supplies were removed prior to the end of the experiment. d) Hares experienced an unexpected viral disease.
B
Insects feeding on the leaves of a plant stimulate the plant to produce more leaves. This is an example of _____. a) aposematism b) compensation c) competition d) an induced defense
B
Refer to Figure 14.10 in your textbook. The figure shows experiments testing the use of a limiting resource (light) on two species of cyanobacteria. Why were both species able to coexist with one another under white light? a) White light contains blue light, which is not limiting to the cyanobacteria. b) White light contains green light, which was limiting to one of the species. c) White light contains purple light, which was limiting to the other species. d) White light contains ultraviolet light, which was limiting to the other species.
B
Some hosts are aided in their defense against parasites by bacteria and fungi. What best describes this defense? a) Biochemical defense b) Symbiont defense c) Immune defense d) Encapsulation
B
The figure shows the relationship between the relative proportion of prey type A that is available in an area and the proportion of prey type A in the total diet of three different predators. Which predator shows evidence that it prefers to eat the more common prey? a) Predator 1 only b) Predator 2 only c) Predator 3 only d) Predator 1 and 2
B
Two similar rodent species are consistently more different from each other when they occupy the same habitat than when they live separately. What is the most likely explanation for the increased divergence when they live together? a) Decreased resource partitioning b) Character displacement c) Competitive exclusion d) Intraspecific competition
B
Two species of birds feed on berries. The birds are active at different times of the day and do not come into contact with one another. Nonetheless, the presence of one species limits the survival and reproduction of the other. What type of competition is this? a) Interference b) Exploitation c) Allelopathy d) Logistic
B
Which example from the chapter shows how predators act through indirect means to alter communities? a) Lizards feeding on spiders b) Golden apple snails and wetland plants c) Geese feeding on marsh plants after the 1970s d) Beetles feeding on Klamath weed
B
Which study shows that parasites can cause population cycling in its host? a) American chestnut and a parasitic fungus b) Red grouse and nematode parasites c) Amphipods and trematode parasites d) Amphipods and trematode parasites
B
Suppose the researchers conducted another experiment to investigate whether other species of defensive symbionts can protect fruit flies from the nematode parasite Howardula. In the first experiment, they screened for beneficial symbiotic bacteria by searching for species similar to Spiroplasma bacteria. They first established a large population of fruit flies and exposed it to the nematode parasite. They then separated the fruit fly individuals into two groups: those without Howardula and those with Howardula. They screened individuals from both groups for seven species of symbionts (A-G). The results are shown in the table. Experiment 1 Percentage of Fruit Fly Individuals with Different Species of Symbionts Symbiont species Treatment A B C D E F G Howardula absent 50 40 80 30 50 95 30 Howardula present 50 90 10 30 75 95 96 Based on the data, which bacterial species appear to be defensive symbionts? Choose all that apply. Species A Species B Species C Species D Species E Species F Species G
B, E, G
A bird species nests in a specific kind of tree. The tree is not harmed by the bird building its nest in the tree's branches, but the bird benefits from the shelter provided by the tree and is better able to successfully raise young. This is an example of ____. a) mutualism b) endosymbiosis c) commensalism d) symbiosis
C
A fundamental niche a) is always the same as a realized niche. b) can only be altered if excess food is available to an organism. c) is often not realized because no one species has exclusive access to all the resources within its fundamental niche. d) is unrestricted by species-species interactions.
C
Based on the Lotka‒Volterra equations, which statement about carrying capacity and species coexistence is most likely true? a) Species with similar resource use but very different carrying capacities are more likely to coexist than species with similar resource use and similar carrying capacities. b) Doubling the carrying capacities of two competing species should increase the likelihood that the species will coexist. c) Species with similar carrying capacities are more likely to coexist than species with different carrying capacities. d) Species with different carrying capacities are more likely to coexist than species with similar carrying capacities.
C
Based on the figure, what is the expected outcome of the competition between species 1 and species 2? a) Coexistence b) Competitive exclusion of species 2 by species 1 c) Competitive exclusion of species 1 by species 2 d) Persistence of one species only; whichever one persists will depend on the initial conditions
C
Character displacement may favor individuals of competing species, resulting in a) resource partitioning, which increases competitive intensity. b) resource partitioning, which increases competitive exclusion. c) one species being able to coexist with a competitor. d) one species being able to outcompete another species.
C
How can herbivores and predators reverse the outcome of competitive interactions? a) They feed on the inferior competitor, which releases the superior competitor from competition. b) They feed equally on either of the competitors. c) They feed on the superior competitor, which releases the inferior competitor from competition. d) All of the above
C
In comparing agriculture practiced by humans and by leaf-cutter ants, which of these statements is the least correct? a) Both groups grow crops, benefiting themselves and the crop species. b) Both groups are highly dependent on food produced through agriculture. c) Both groups have been practicing farming for about the same length of time. d) Agriculture has allowed both groups to develop extremely high populations.
C
In his experiments with different competing pairs of Paramecium species, Gause found that sometimes both species persisted and sometimes only one species did. Which hypothesis did Gause propose in order to explain the cases in which both species persisted? a) One species was a much better competitor than the other. b) Periodic disturbance allowed for coexistence. c) The two species tended to use different resources. d) The two species exhibited only interference competition, not exploitative competition.
C
In which of the following cases could positive interactions evolve over time? a) The costs of the interaction consistently outweigh its benefits. b) The costs and benefits of the interaction are the same for both species. c) The benefits of the interaction consistently outweigh its costs. d) A symbiotic mutualism switches to a parasitism.
C
Refer to the data provided above. Which bacterial species may have been negatively affected by parasitism? Choose all that apply. Species A Species B Species C Species D Species E Species F Species G
C
Refer to the information provided in the previous 2 questions. Suppose in a second experiment the researchers follow, for seven generations, the percentage of fruit fly individuals that harbor the symbiont Species B with and without Howardula. They find the results shown in the table. Examine the data in the table. Do the results indicate that there is a cost to flies for harboring Species B symbiont? Experiment 2 Percentage of Fruit Fly Individuals Harboring Species B Symbiont Generation Treatment 1 2 3 4 5 6 7 Howardula absent 39 43 30 22 15 6 1 Howardula present 75 80 86 92 97 99 99 a) There is no cost to flies for harboring species B symbiont because the symbiont protects the flies against Howardula. b) There is no cost to flies for harboring Species B symbiont because the frequency of flies harboring the symbiont decline in the absence of the parasite. c) There is a large cost to flies for harboring Species B symbiont because the frequency of flies harboring the symbiont decline in the absence of the parasite. d) There is a large cost to flies for harboring Species B symbiont because the frequency of flies harboring the symbiont increases in the presence of the parasite.
C
Refer to the table. Year Fungus upper Fungus lower Host upper Host lower 1987 65 54 -7 -21 1990 63 47 -2 -9 1993 70 54 -3 -8 1996 67 52 5 -4 1999 64 49 15 3 2002 71 55 22 8 2005 68 54 20 9 The table contains data on the effects of symbiosis between a fly (host) and a fungus over many years. It shows the upper and lower bounds for the effects of the association; positive numbers denote net benefits and negative numbers denote net costs. (If zero is between the upper and lower bounds, consider the effect to be zero, since it is statistically indistinguishable from zero.) According to the table, the relationship between the fungus and the fly in 1996 was a _____. a) mutualism b) competitive interaction c) commensalism d) host‒parasite interaction
C
The RNE (relative neighbor effect) measures growth of a target plant species in the presence and absence of neighboring species. The figure shows graphs of the RNE at eleven sites around the world. RNE was measured at high and at low elevations at each site. RNE values above zero (blue) indicate that neighboring plants increased the growth of target species; RNE values below zero (red) indicate that neighbors decreased target species growth. What type of ecological interaction did plants show at high elevations and at low elevations, respectively? a) High: mutualists; low: mutualists b) High: mutualists; low: parasites c) High: mutualists; low: competitors d) High: competitors; low: mutualists
C
The competitive exclusion principle states which of the following? a) If species use the same unlimited resource, they cannot competitively coexist. b) If species use the same limited resource, they sometimes competitively coexist. c) If species use the same limited resource, they cannot competitively coexist. d) If the species use the same limited resource, they always competitively coexist.
C
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 _______. a) increase; communities of small shrubs and forbs b) increase; tundra c) decrease; communities of small shrubs and forbs d) decrease; alpine forest
C
To incorporate the effects of competition, the logistic equation of one species can be modified by doing which of the following? a) Adding a competition coefficient, which is a constant used to indicate the strength of interspecific competition b) Subtracting a competition coefficient, which is a constant used to indicate the strength of intraspecific competition c) Subtracting a competition coefficient, which is a constant used to indicate the strength of interspecific competition d) Subtracting a competition coefficient, which is a constant used to indicate the logistic growth of the other species
C
What are some factors that do not affect whether predator-prey populations cycle? a) Evolutionary changes to the prey population b) The dependence of predator and prey population abundances on one another c) The initial and ending numbers of predators and prey d) Habitat complexity, predator dispersal, and spatial refuges of the prey
C
What does the figure indicate about the competitive outcome of species 1 and species 2? a) Species 1 will outcompete species 2. b) Species 2 will outcompete species 1. c) will coexist at lower population sizes. d) Either species 1 or species 2 will outcompete the other depending on their population sizes.
C
What is an advantage of ectoparasitism? a) Exposure to the external environment b) Avoidance of natural enemies c) Dispersal from one host individual to another d) Ease of obtaining digested food of the host
C
What is the advantage for a male cricket parasitized by hairworms to seek out water? a) By hydrating the cricket, the water decreases the negative effects of the parasite. b) Female crickets live near the water; by going to the water, the infected cricket can increase his chances of mating before the parasite kills him. c) There is no advantage for the cricket; the cricket's behavior is advantageous only to the parasite. d) There is no advantage for the infected cricket, but by going to the water and drowning, the cricket reduces the prevalence of parasitism in the species.
C
When a population of the caddisfly Glossosoma nigrior was infected by a fungal pathogen, what were the community consequences and why? a) A decrease in the abundance of dozens of species, all of which relied on the caddisfly b) An increase in the abundance of dozens of species, all of which relied on the caddisfly c) An increase in the abundance of dozens of species, all of which were negatively affected by herbivory of the caddisfly d) An increase in the abundance of dozens of species, all of which were negatively affected by carnivory of the caddisfly
C
Which criterion is most important in determining whether an ecological relationship is a symbiosis? a) Whether both parties benefit b) Whether the parties are evolutionarily closely related to each other c) The degree of physical proximity between the two parties d) The number of parties in the interaction
C
Which factor is not considered in host-parasite population models? a) The number of susceptible hosts b) The number of infected hosts c) The number of susceptible parasites d) The number of recovered and immune hosts
C
Which of the following characterizes mutualisms? a) Both partners can provide habitat. b) Both partners can provide pollination. c) One partner can provide food and the other can provide habitat. d) One partner can provide food but the other partner provides nothing.
C
Which statement about carnivorous plants is false? a) Many carnivorous plants are found only in environments where soils are poor in nutrients. b) Carnivorous plants like Venus flytraps occasionally consume relatively large animals, including frogs and slugs. c) Carnivorous plants typically have very extensive root systems. d) Many pitcher plants have an internal layer of flaky wax that assists in prey capture.
C
Why do carnivores tend to be generalists and have broad diets? a) Encounter rate is high and handling time is low, which favors broad prey choices. b) Encounter rate is low and handling time is high, which favors broad prey choices. C) Encounter rate and handling time is low, which favors broad prey choices. D) Encounter rate and handling time is high, which favors broad prey choices.
C
Why don't host-parasite interactions show an ever-escalating coevolutionary arms race? a) Each species has too much genetic diversity. b) There is a trade-off in which a parasite's counterdefenses have no costs to growth, reproduction, or survival. c) There is a trade-off in which a host's defenses have costs to growth, reproduction, or survival. d) There is a trade-off in which a host's defenses have no costs to growth, reproduction, or survival.
C
Based on data in the figure, a newly discovered seed could be hypothesized to have a nitrogen content of _______? a) 0.003% b) 0.03% c) 0.3% d) 3%
D
Both competition and facilitation are important in a) species interactions such as those between ants and fungi or cockroaches and protists. b) plant species that interact at low mountain elevations. c) plant species that interact at high mountain elevations. d) plant species that interact at high and low mountain elevations.
D
Coevolution is when populations of two interacting species evolve in which of the following ways? a) Separately, each in response to the selection pressures imposed by the other b) Separately, each in response to the selection pressures imposed by the environment c) Together, each in response to the selection pressures imposed by the environment d) Together, each in response to the selection pressures imposed by the other
D
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? a) The wasps and the blowflies are engaged in a predatory relationship. b) The wasps are parasitoids. c) The wasps can be thought of as both predators and parasites, albeit unusual ones. d) The wasps are generalist
D
How can competition and the physical environment modify the distribution of species? a) As we saw with barnacles, when the superior competitor was removed, the inferior competitor expanded its range to less stressful lower intertidal zones. b) As we saw with chipmunks, when chipmunk species co-occurred on mountains, there was little overlap in their distributions because of competition. c) As we saw with chipmunks, when chipmunk species lived alone on mountains, their distributions expanded to all but the highest mountain elevations. d) All of the above
D
How can positive interactions affect the distribution and abundance of species? a) By affecting the growth of one or the other species b) By affecting the reproduction of one or the other species c) By affecting the survival of one or the other species d) All of the above
D
How do predators mostly affect the distribution and abundance of their prey? a) By directly affecting the prey of the prey b) By indirectly affecting the prey of the prey c) By increasing the growth, survival, and/or reproduction of the prey d) By reducing the growth, survival, or reproduction of the prey
D
How does one determine whether predator and prey populations are cycling? a) Solve for the population growth equation of each species when they reach the zero growth isocline. b) Plot the isocline for both the prey and predator populations in graphical form. c) Both a and b d) None of the above
D
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. a) exploitative b) cryptic c) apomitic d) aposematic
D
Refer to the table. Year Fungus upper Fungus lower Host upper Host lower 1987 65 54 -7 -21 1990 63 47 -2 -9 1993 70 54 -3 -8 1996 67 52 5 -4 1999 64 49 15 3 2002 71 55 22 8 2005 68 54 20 9 The table contains data on the effects of symbiosis between a fly (host) and a fungus over many years. It shows the upper and lower bounds for the effects of the association; positive numbers denote net benefits and negative numbers denote net costs. (If zero is between the upper and lower bounds, consider the effect to be zero, since it is statistically indistinguishable from zero.) According to the table, the relationship between the fungus and the fly in 1990 was a ____. a) mutualism b) competitive interaction c) commensalism d) host‒parasite interaction.
D
Suppose that two species of Darwin's finches live on the same island and eat seeds, but one species tends to eat larger seeds than the other one does. Based on this observation, we can conclude that these species are engaged in _____. a) competitive exclusion b) allelopathy c) interference competition d) resource partitioning
D
The competitive exclusion principle states that the _______ species prevents another species from using essential resources, causing the _______ species to become locally extinct. a) smaller; larger b) larger; smaller c) inferior; dominant d) dominant; inferior
D
What are two ways to control the spread of a disease? a) Decrease the susceptible hosts and increase the threshold density b) Increase vaccines and programs that decrease the transmission rate c) Kill or recover infected hosts d) All of the above
D
What factor(s) can affect the outcome of coevolution in host-parasite interactions? a) The genetic diversity of the host b) The mutation rate of the parasite c) The lethality of the parasite d) All of the above
D
What is one type of pathogen vector that might cause disease spread in humans during climate change and why? a) Rodents benefiting from warmer conditions b) Mosquitos benefiting from increasing CO2 c) Sand flies benefiting from increasing wet conditions d) Mosquitos benefiting from warmer conditions
D
What type of mutualistic interaction has been shown to have effects on nutrient cycling? a) Yuccas and yucca moths b) Acacia trees and acacia ants c) Reef fishes and cleaner fishes d) Plants and mycorrhizal fungi
D
Which mechanism do animals not use to avoid being eaten? a) Large size b) Resembling a less palatable animal c) Mimicking an organism or background to remain hidden d) Changing their behavior to make them more noticeable correct
D
Which mechanism(s) do plants use to avoid being eaten? a) Secondary compounds that are toxic or reduce nutrition b) Structural defenses such as spines or hairs c) Compensation by stimulating new plant growth d) Both a and b
D
Which of the following findings from Connell's experiments with intertidal barnacles is false? a) In both species, the extent of the distribution of larvae is greater than that of adults. b) One species is excluded from the top of the intertidal zone due to sensitivity to desiccation. c) One species is excluded from the bottom of the intertidal zone due to competition with the other species. d) Both species of barnacles survived better when tidal disturbances removed patches of competitive mussels.
D
Why are parasites so abundant and why do they tend to be specialists? a) Most host species have multiple parasites and those parasites have parasites. b) Parasites tend to be specialists because they live on or in their hosts. c) Parasites tend to be specialists because they feed on certain parts of the host's body. d) All of the above
D
Why do herbivores tend to be specialists and have narrow diets? a) Encounter rate is high and handling time is low, which favors narrow prey choices. b) Encounter rate is low and handling time is high, which favors narrow prey choices. c) Encounter rate and handling time is low, which favors broad prey choices. d) Encounter rate and handling time is high, which favors broad prey choices.
D
Why is there a conflict of interest between the partners in a mutualism? a) They are always altruistic. b) The benefits provided by each species come never come at a cost. c) Natural selection favors cheaters but also rewards for overexploiting a partner. d) Natural selection favors cheaters but also penalizes for overexploiting a partner.
D
