Deck 55: Species Interactions

Question 1

Which interaction is the clearest example of amensalism?

A) A seabird, the Atlantic puffin, uses nests originally made by rabbits.
B) Pilot fish live around sharks, feeding on shark parasites and leftover food.
C) An algal bloom causes many fish deaths, but fish deaths do not benefit algae.
D) Algae live on the backs of spider crabs, camouflaging the crabs from predators.
E) Tapeworms live inside a dog's intestine, eating the dog's food and depriving it of nutrients.

Answer 1

C

Question 2

Refer to the table showing major types of interactions between species and the positive or negative influences of each interaction type. What symbols should replace the "Y" and "Z," respectively, in the table?

A) ‒ and +
B) + and +
C) - and 0
D) + and 0
E) 0 and 0

Answer 2

B

Question 3

Two species of beetles are herbivores on the same host plant, and the presence of either species reduces the population growth of the other.The relationship between the beetles is therefore best described as

A) mutualism.
B) predation.
C) herbivory.
D) competition.
E) amensalism.

Answer 3

D

Question 4

Two species of lionfish have recently invaded the Caribbean, the Gulf of Mexico, and the Western Atlantic region.Comparing these predatory fishes with their native competitors, the activity of the lionfish could best be classified as

A) strong predators with asymmetrical effects on competitors.
B) strong predators with symmetrical effects on competitors.
C) weak predators with symmetrical effects on competitors.
D) weak predators with asymmetrical effects on competitors.
E) medium-strength predators with symmetrical effects on competitors.

Question 5

Another way to describe coevolution is

A) amensalism.
B) commensalism.
C) natural selection.
D) reciprocal adaptation.
E) character displacement.

Question 6

In an experiment involving two annual plants that grow in disturbed habitats, equal numbers of seedlings of the two species were grown together.Plant A grew much larger than plant B during the same time period.Would this interaction be considered asymmetrical? Why or why not?

A) Yes; plant A grew larger than plant B.
B) Yes; they were growing in a disturbed habitat.
C) No; both plants remained healthy and continued to grow.
D) No; reproductive fitness, not size, determines symmetry.
E) It is not clear what caused the difference in growth.

Question 7

Refer to the table showing major types of interactions between species and the positive or negative influences of each interaction type. What type of interaction is represented by the "X" in the table?

A) Amensalism
B) Antagonism
C) Commensalism
D) Competition
E) Herbivory

Question 8

Which is an example of a mutualistic interaction?

A) A virus infects a bird, thus reducing the bird's fecundity.
B) A blue jay chases sparrows from a bird feeder so it can eat the seeds.
C) Barnacles remain safe by riding on a whale, while the whale is unaffected.
D) A wasp lays its eggs inside a caterpillar, and the hatched wasp larvae consume the caterpillar.
E) A bacterium lives in a plant's roots and fixes nitrogen for the plant, which in turn provides nutrients to the bacterium.

Question 9

A survey of predator-prey relationships shows that the fastest predators are usually found in regions where the fastest prey are found.The most likely explanation for this is

A) reciprocal adaptations.
B) character displacement.
C) the Batesian principle.
D) the Müllerian principle.
E) exploitation competition.

Question 10

Which interaction is a positive interaction?

A) Parasitism
B) Predation
C) Herbivory
D) Competition
E) Mutualism

Question 11

Which relationship has negative consequences for both species involved?

A) Predation
B) Competition
C) Amensalism
D) Parasitism
E) Mutualism

Question 12

Which relationship is least likely to result in coevolution?

A) Mutualism
B) Parasitism
C) Predation
D) Competition
E) Amensalism

Question 13

The relationship between a zebra and the lion that eats it is an example of

A) predation.
B) competition.
C) mutualism.
D) commensalism.
E) amensalism.

Question 14

Although most herbivory harms the plant, some herbivorous interactions do not.Which is not a harmful interaction?

A) Leaf miner insects feed on sugars in leaf cells without killing the leaves.
B) Aphids pierce stems and consume plant sap but do not damage other plant parts.
C) Nematodes feed on the starches in plant roots; the roots live, but their growth is slowed.
D) Gypsy moth caterpillars feed on the leaves of oak and aspen, defoliating and stressing the trees.
E) Bears eat blueberries, then excrete blueberry seeds throughout the forest, and the seeds germinate.

Question 15

A cow's rumen, or first stomach, provides the ideal environment for a variety of microbes.When a cow consumes grass, these microbes digest the grass, releasing nutrients, which both they and the cow use.While most of the microbes remain in the rumen, some are killed during digestion and provide additional nutrition for the cow.This complex relationship between the cow and its microbes has features of which two categories of interactions?

A) Competition and mutualism
B) Mutualism and predation
C) Commensalism and amensalism
D) Predation and parasitism
E) Amensalism and competition

Question 16

Suppose the fecal matter from dogs helps fertilize a species of grass, thus increasing the grass's ability to grow in a particular area.The relationship between the dogs and the grass would be described as

A) mutualism.
B) amensalism.
C) herbivory.
D) competition.
E) commensalism.

Question 17

Although lichens look like single organisms, they are actually an association between a fungus and a photosynthetic partner, usually an alga.The lichen association is considered mutualistic, but the relationship also shows some features of parasitism.Which fact about lichens suggests parasitism rather than mutualism?

A) One kind of fungus can partner with more than one kind of alga.
B) The fungal species that occur in lichens almost never occur outside of lichens.
C) Nutrients always flow from algae to fungi but do not always flow from fungi to algae.
D) Some lichens live in habitats where no fungi or algae can survive except within lichens.
E) Lichens most often reproduce asexually with small clusters of cells from both partners.

Question 18

The South American tree sloth feeds on leaves and buds, which are digested by bacteria that inhabit the sloth's stomach.It is difficult for predators to see the sloth in a tree, because it is tinted green from the cyanobacteria that live in its fur.A variety of nonbiting insects also live in the fur but appear not to affect the sloth.This suggests that the sloth has mutualistic interactions with which two sets of organisms?

A) Leaves and buds, as well as digestive bacteria
B) Digestive bacteria and cyanobacteria
C) Cyanobacteria and insects
D) Insects, as well as leaves and buds
E) Leaves and buds, as well as cyanobacteria

Question 19

Plants and mycorrhizae (fungi that grow in association with plant roots) are usually mutualistic.The fungus absorbs water and minerals, such as phosphorus, from the soil, which the plant uses.The plant provides the fungus with carbohydrates.In soils where phosphorus is low, nutrient transfer from fungus to plant may increase plant fitness.But in very fertile soils, the net benefit of the interaction may become negative, with the fungus acting more as a parasite than a mutualist.Which is the best description of the change in this interaction?

A) It begins as parasitism and becomes mutualism.
B) It begins as mutualism and becomes competition.
C) It begins as asymmetrical and becomes symmetrical.
D) It moves along a relationship continuum in response to environmental changes.
E) It is an evolutionary change in interacting species, leading to a relationship change.

Question 20

While pursuing its prey, a bear destroys a shrub.The relationship between the bear and the shrub would be described as

A) herbivory.
B) competition.
C) amensalism.
D) commensalism.
E) predation.

Question 21

Eastern tent caterpillars are social nesters that spin weblike nests, or tents, to which they keep adding layers as they molt and grow.The caterpillars leave the tent several times each day to feed on the leaves of their host tree.Many potential predators will attack one tent caterpillar and then refrain from attacking or eating others.Two possible deterrents to predation are the stiff hairs present on caterpillars (but not pupae) and toxic cyanide compounds, which caterpillars absorb from cherry trees where they nest and feed.Researchers wish to determine whether either of these actually deters predators.Which study design would most clearly distinguish between the two possible deterrents?

A) Offer only pupae to predators.
B) Offer both the toxic caterpillars and their pupae to predators.
C) Raise caterpillars on nontoxic leaves, and offer only nontoxic caterpillars to predators.
D) Raise some caterpillars on nontoxic leaves, and offer both toxic and nontoxic caterpillars to predators.
E) Raise some caterpillars on nontoxic leaves, and offer both toxic and nontoxic caterpillars and pupae to predators.

Question 22

Climate change leads to much drier climates in some areas.Over time, some plant species will likely show genetic changes related to their ability to withstand drought.In this situation, the precipitation level is acting as

A) a biotic agent of evolution.
B) an abiotic agent of evolution.
C) a biotic agent of coevolution.
D) an abiotic agent of coevolution.
E) an agent of local adaptation but not evolution.

Question 23

A skunk's defense against predators includes a noxious spray combined with sharply contrasting black-and-white coloration.This combined defense is an example of

A) crypsis.
B) amensalism.
C) Batesian mimicry.
D) character displacement.
E) warning coloration.

Question 24

Adult monarch butterflies contain glycosides that are toxic to predators.The glycosides originate from

A) inherited genes that produce glycosides in caterpillars.
B) inherited genes that produce glycosides in pupae.
C) inherited genes that produce glycosides in adult butterflies.
D) the milkweed plants that the caterpillars eat.
E) the nectar that adult butterflies drink.

Question 25

Which feature is not an adaptation usually associated with predators?

A) Strength
B) Swiftness
C) Large size
D) Protective body surface
E) Well-developed senses

Question 26

Many species of algae, seaweed, and sea grasses live on and around coral reefs.Herbivores, including most fish, sea urchins, and gastropods (snails and sea slugs), graze on them.In this environment, are herbivores more likely to be generalists or specialists?

A) Generalists, because it is easier for grazers to eat whatever is available
B) Generalists, because there are many types of algae to choose from
C) Specialists, because specialization allows resource partitioning
D) Specialists, because it is more efficient for grazers to pick a single species
E) Either generalists or specialists, because coral reef diversity makes both options possible

Question 27

Which method of prey defense is an example of mimicry?

A) A fawn's coat of white spots on brown resembles dappled sunlight and shade.
B) A gray tree frog's skin colors resemble bark patterns of trees.
C) A katydid's wing shape and colors resemble green leaves with veins.
D) A spicebush caterpillar's large, spotted head resembles a snake's head and eyes.
E) A snowshoe hare's white winter coat resembles snow.

Question 28

Bombardier beetles defend themselves by means of

A) crypsis.
B) stiff hairs.
C) chemical defenses.
D) rapid fleet from predators.
E) mimicry of more toxic beetles.

Question 29

Which prey animal is using a morphological form of defense against predators?

A) The frog that has a toxin in its skin
B) The katydid that looks like a dead leaf
C) Antelopes that remain together in herds
D) The opossum that "plays dead"
E) The octopus that shoots jets of ink to confuse predators

Question 30

Eastern tent caterpillars are social nesters that spin weblike nests, or tents, to which they keep adding layers as they molt and grow.The caterpillars leave the tent several times each day to feed on the leaves of their host tree.Many predators attack caterpillars feeding outside the tent.Which caterpillar behavior would be least advantageous in minimizing predation while the caterpillars are feeding?

A) Spreading out in the tree and feeding separately
B) Becoming motionless when a predator is detected
C) Leaving the tent at different times, rather than all leaving at once
D) Feeding at the same time each day, rather than feeding throughout the day
E) Returning to the tent as soon as feeding is finished

Question 31

The opposite of crypsis is

A) mutualism.
B) commensalism.
C) antagonism.
D) warning coloration.
E) character displacement.

Question 32

If a predator species were incapable of learning, which of the following would be the least adaptive for its prey?

A) Crypsis
B) Warning coloration
C) Playing dead
D) Speed
E) Small size

Question 33

A newly discovered frog species secretes toxic chemicals.Compared with closely related species without chemical defenses, members of this new frog species will most likely

A) be faster.
B) be bigger.
C) be stronger.
D) have thicker skins.
E) have brighter colors.

Question 34

Which situation can be considered an example of an abiotic factor acting as an agent of natural selection?

A) A viral disease wiped out most of a mouse population, but those who survived were immune to the virus.
B) Lighter-colored moths on tree trunks were more visible to predators and were more likely to be preyed upon.
C) Polar bears with genes for thicker coats were more able to survive intensely cold temperatures, and more of their offspring survived.
D) As water temperatures changed along a north-south gradient, fish populations of the same species produced different amounts of antifreeze-like chemicals.
E) A new grasshopper species invaded a prairie habitat and quickly stripped the nongrassy perennial plants; animals dependent on these plants moved or died out.

Question 35

American toads are prey for a number of vertebrate predators.The toads themselves also prey on a variety of insects.Which characteristic most benefits toads in their role as potential prey, rather than as potential predators?

A) Winter hibernation
B) Mottled brown coloration
C) Habitat of dense vegetation
D) Tendency to be active mostly at night
E) Secretion of toxic chemicals through their skin

Question 36

Three species of snails that are toxic to their bird predators have evolved similar patterns of coloration that help notify the birds of their poisonous nature.This phenomenon is known as

A) Müllerian mimicry.
B) Batesian mimicry.
C) character displacement.
D) crypsis.
E) mutualism.

Question 37

Some nontoxic female swallowtail butterflies resemble other butterfly species that are toxic.This phenomenon is known as

A) character displacement.
B) Müllerian mimicry.
C) Batesian mimicry.
D) coevolution.
E) crypsis.

Question 38

Eastern tent caterpillars are social nesters that spin weblike nests, or tents, to which they keep adding layers as they molt and grow.The caterpillars leave the tent several times each day to feed on the leaves of their host tree.The large, conspicuous caterpillar tents attract some predators and provide protection from others.Based on features of the tents, which animal would be most able to attack caterpillars inside their tents?

A) Spider
B) Bat
C) Toad
D) Bird
E) Squirrel

Question 39

Hyenas can obtain as much as three-fourths of their prey by hunting, but they also scavenge the kills of other carnivores.A group of hyenas can displace any carnivore except lions from a kill.Which characteristic would be most useful to hyenas in both hunting their own prey and scavenging kills from other predators?

A) Being highly territorial
B) Having excellent eyesight
C) Being adept at teamwork
D) Having excellent speed and stamina
E) Having the ability to smell carrion

Question 40

Stinging bees, stinging wasps, and nonstinging hover flies all have black-and-yellow striped abdomens.Which type(s) of mimicry are these three types of insects expressing?

A) The bees and the flies are Müllerian mimics, and the wasps are Batesian mimics.
B) The bees and the wasps are Müllerian mimics, and the flies are Batesian mimics.
C) The bees and the wasps are Batesian mimics, and the flies are Müllerian mimics.
D) All three types of insects are Müllerian mimics.
E) All three types of insects are Batesian mimics.

Question 41

Which type of organism is most typical of herbivores?

A) An insect that completely destroys its food plant
B) An insect that eats a small percentage of its food plant
C) An insect that eats a large percentage of its food plant
D) A vertebrate that eats a small percentage of its food plant
E) A vertebrate that eats most or all of its food plant

Question 42

In Paine's classic study of sea star predation on mussel populations, he showed that in the absence of sea stars, experimental plots lost approximately half of the sessile invertebrate species usually present.This result suggests that

A) mussels act as a keystone species in the rocky shore community.
B) high prey density is necessary to maintain community species diversity.
C) predators can maintain community species diversity by controlling prey density.
D) some sessile invertebrate species can survive only in the presence of mussels.
E) some sessile invertebrate species can survive only in the presence of sea stars.

Question 43

Which of these interactions does not represent a typical parasite-host interaction?

A) A virus is transmitted by mosquitoes and causes a nonfatal disease in humans.
B) Leeches attach to a boy swimming in a pond; he removes them as quickly as possible.
C) Tapeworms become established in a cat and are transmitted to other cats in the household.
D) A wasp lays eggs in a moth caterpillar; hatched wasps consume and kill the moth caterpillar.
E) The E. coli bacterium lives normally in the human intestine, but when ingested, it causes disease.

Question 44

A small population of Canada lynx feeds on Arctic hares.Then snowshoe hares (the lynx's favorite prey) are introduced.The snowshoe hares reproduce rapidly, and their population explodes.Based on your knowledge of predator-prey interactions, what changes would you expect in the lynx population and in the population of Arctic hares, the lynx's previous prey?

A) Lynx and Arctic hare populations would both increase.
B) Lynx and Arctic hare populations would both decrease.
C) Lynx populations would increase and Arctic hare populations would decrease.
D) Lynx populations would decrease and Arctic hare populations would increase.
E) Lynx populations would increase and Arctic hare populations would not change.

Question 45

An herbivore species would most likely exert strong selective pressure on its host plant species if the herbivore eats

A) a very small percentage of the plant biomass.
B) throughout the spring and summer but eats only leaves.
C) a large part of the plant biomass, including the entire flower.
D) a large part of the plant biomass in late summer, after the plant reproduces.
E) a small part of the plant biomass in early spring, during plant reproduction.

Question 46

Most plants defend themselves against herbivory by means of

A) warning coloration.
B) crypsis.
C) thorns and spines.
D) thick coverings.
E) chemical defenses.

Question 47

Microscopic study of the contact lens fluid of a person with an eye infection revealed a series of four nested parasites: an amoeba, which contained a giant virus, which contained a smaller virus, which contained chunks of parasitic DNA.How could these four parasites best be characterized?

A) All are symbiotic microparasites, but only the amoeba is known to be pathogenic.
B) All are symbiotic microparasites that are also pathogens.
C) All are microparasites that are symbiotic but not pathogenic.
D) All are symbiotic microparasites, but only viruses, not amoebae, are pathogenic.
E) The amoeba is a macroparasite, the others are microparasites, and none are pathogenic.

Question 48

Many scientists think the great number of parasite species on Earth can be explained by the specialization parasites have undergone and continue to undergo.Which factor is likely most responsible for the continued evolution of new forms of parasites?

A) Highly resistant host immune systems
B) Stable, unchanging host environments
C) Constantly changing host environments
D) The ability of most parasites to kill their hosts and move to new ones
E) The ability of parasites to become more deadly with each generation

Question 49

In nature, predator-prey cycles can continue for many years.In laboratory cultures, both populations quickly die off unless new individuals are periodically introduced (i.e., immigration occurs).Based on this information, cycles in nature might be maintained by any of these factors (or some combination of them) except

A) strong predation resulting in rapid evolution of prey defenses.
B) pockets of prey that survive and are able to rebuild the population.
C) continuous immigration of both predator and prey to maintain populations.
D) inherent stability exerting control from within the predator-prey interaction.
E) habitat and species complexity preventing complete elimination of predator or prey.

Question 50

In pregnant women, the Zika virus causes serious birth defects.It is spread by the bite of the Aedes aegypti mosquito, which contracts it from an infected human.It must replicate and spread within the mosquito before it can infect a human.Infected humans can spread the virus through sex and from mother to unborn child.In this relationship, how can the Zika virus be characterized?

A) A microparasite and an ectoparasite
B) A microparasite and an endoparasite
C) A macroparasite and an ectoparasite
D) A macroparasite and an endoparasite
E) A macroparasite, an endoparasite, and a pathogen

Question 51

The graph below shows cycles of predators (lynx) and prey (snowshoe hares) over nearly a century.During this time, people were trapping both lynx and hares, thus limiting their populations. If trapping of both species declined, what changes would be expected to occur in the hare and lynx populations?

A) Cycles would continue but probably at higher levels.
B) Cycles would continue but probably at lower levels.
C) Both hare and lynx populations would increase, and cycles would stop.
D) Both hare and lynx populations would decrease, and cycles would stop.
E) Both hare and lynx populations would increase to their carrying capacities and level off.

Question 52

The H1N1 influenza virus responsible for the 2009 pandemic is an example of

A) a microparasite.
B) a macroparasite.
C) an ectoparasite.
D) a mutualist.
E) a commensal.

Question 53

The biochemical diversity of plants is primarily due to

A) adaptations to different soils.
B) adaptations to different temperatures.
C) coevolution with herbivores.
D) adaptations to different levels of moisture.
E) coevolution with commensals.

Question 54

A bird is infested with the bloodsucking larvae of blowflies.The blowfly larvae fall off the bird and are themselves infested with parasitic wasps.The wasps contain a parasitic bacterium, which in turn is infested with bacteriophages, or parasitic viruses.This multitiered system could be considered evidence for

A) the importance of birds as parasite hosts.
B) the importance of bacteria and viruses as disease agents.
C) microparasites controlling populations of macroparasites.
D) macroparasites controlling populations of microparasites.
E) specialization resulting in the large number of parasite species.

Question 55

The best characterization of pathogenic organisms is that all

A) cause death.
B) cause disease.
C) are bacteria.
D) are microparasites.
E) are macroparasites.

Question 56

A parasite lives in a chimpanzee's fur and is easily located and picked off by the troop's other chimpanzees during grooming.This parasite is both an

A) ectoparasite and a macroparasite.
B) ectoparasite and a microparasite.
C) endoparasite and a macroparasite.
D) endoparasite and a microparasite.
E) endoparasite and a prey organism.

Question 57

Butterfly caterpillars and adults are herbivores, and they exhibit many adaptations to this lifestyle.Which characteristic of butterflies is least likely to be an adaptation to herbivory?

A) Female butterflies lay eggs on plants.
B) Caterpillars molt about five times before pupation.
C) Caterpillars feed continuously and move only short distances.
D) Adults have straw-like mouthparts.
E) Adults are active during daylight, when most flowers are open.

Question 58

Which feature of head lice is least likely to be an adaptation for their lifestyle as ectoparasites on humans?

A) Flattened body
B) No wings
C) Grasping legs
D) Larger females
E) Piercing mouthparts

Question 59

Which type of organisms would be most likely to evolve adaptations that would enable them to grasp onto and maintain a tight grip on their hosts?

A) Amensal
B) Ectoparasitic
C) Microparasitic
D) Herbivorous
E) Endoparasitic

Question 60

Which type of animal has most likely evolved specialized detoxification systems?

A) An avian predator
B) A tick that lives as an ectoparasite
C) A mammalian herbivore that eats a variety of plant species
D) An insect whose larvae feed on the leaves from a single host plant
E) A bumblebee that obtains nectar while pollinating flowers from different species

Question 61

After the introduction of the American mink into Belarus, the native European mink became larger, and the American mink gradually decreased in size.These changes most likely occurred because of

A) competitive exclusion.
B) interference competition.
C) character displacement.
D) Müllerian mimicry.
E) Batesian mimicry.

Question 62

According to studies, when ant colonies are removed from acacia trees, the acacias show decreased growth and increased mortality, due to repeated removal of their growing tips by herbivores.This suggests that the primary benefit that acacia trees receive from their association with ants is

A) seed transport.
B) pollen transport.
C) nitrogen products.
D) potassium products.
E) protection from predators.

Question 63

Two species of barnacles, stellate and rock barnacles, occupy the rocky intertidal zone of the Scottish coast and illustrate factors that can determine species distribution in a community.Larvae of both species settle throughout the intertidal zone, but adult barnacles occupy specific zones.The smaller stellate barnacle lives only in higher zones, where the environment dries out between high tides.The larger, faster-reproducing rock barnacle lives only at lower zones.Differences in the distribution of larval and adult barnacles suggest that stellate barnacles are primarily restricted by _______ and rock barnacles are restricted by _______.

A) water availability; cold temperatures
B) predation; competition
C) competition; predation
D) competition; water availability
E) parasitism; cold temperatures

Question 64

At a swim meet, all the swimmers in a race want to place first, but only the fastest swimmer can do so.The is an example of

A) interspecific competition.
B) interference competition.
C) competitive exclusion.
D) resource partitioning.
E) exploitation competition.

Question 65

In the coral reef environment, the ivory bush coral competes for space with surrounding seaweed.The red-ridged clinging crab feeds on seaweed but is also preyed on by surrounding fish.The crab hides in the coral branches and feeds only on the seaweed closest to the coral.Would the crab-coral interaction be best classified as mutualism or commensalism?

A) Commensalism, because the crab receives protection and the coral is unaffected
B) Commensalism, because the crab has less competition and the coral is unaffected
C) Commensalism, because the crab is unaffected and the coral has less competition
D) Mutualism, because both the crab and the coral receive more food from the interaction
E) Mutualism, because the crab receives protection and the coral has less competition from seaweed

Question 66

Two similar species of lemurs exist in Madagascar.One species eats leaves from the understory of trees, and the other eats leaves from the tops of those trees.This phenomenon would be described as

A) competitive exclusion.
B) interference competition.
C) exploitation competition.
D) resource partitioning.
E) character displacement.

Question 67

Two species of woody shrubs live in close proximity and compete for limited resources.One species produces chemicals through its roots that limit the growth of the other.The production of these chemicals is a form of

A) intraspecific competition.
B) interference competition.
C) competitive exclusion.
D) resource partitioning.
E) exploitation competition.

Question 68

Which interaction does not cause a species' realized niche to be more restricted than its fundamental niche?

A) Parasitism
B) Predation
C) Mutualism
D) Exploitation competition
E) Interference competition

Question 69

Leafcutter ants cut large amounts of leaf material and carry it back to their nests, where they use it in "fungal gardens" to feed and grow a fungus.The fungus depends on the ants for its food and is also the primary food for the ants, themselves.This interaction between ants and fungi is best described as

A) obligate mutualism.
B) obligate parasitism.
C) obligate commensalism.
D) facultative mutualism.
E) facultative commensalism.

Question 70

Some types of pine trees are attacked and fed on by pine bark beetles.As the beetles feed, they girdle the trees, destroying the phloem layer and killing the trees.Pine bark beetles are also associated with the blue stain fungus, which grows in their frass (feces).As they attack the trees, the beetles also inject the fungus.The fungal hyphae grow into the tree and follow its xylem cells, blocking the flow of xylem and causing rapid tree death.Suppose pine bark beetles that lacked the blue stain fungus attacked pine trees.How would the absence of the blue stain fungus be likely to affect the death rate of pines?

A) There would be little effect; the beetles would still kill the trees.
B) It would be lower; only beetles, not fungus, would be killing the trees.
C) It would be higher; beetles would be more efficient without the fungus.
D) It would be high but slower; only beetles, not fungus, would be killing the trees.
E) It would be high but faster; beetles would be more efficient without the fungus.

Question 71

Two species of yeast can persist indefinitely on agar in the lab, but when they are grown together under similar conditions, only a single species remains after a few days.This interaction is an illustration of

A) competitive exclusion.
B) interference competition.
C) intraspecific competition.
D) character displacement.
E) resource partitioning.

Question 72

A robin is feeding at a bird feeder.A second robin arrives, and the first robin chases the second one away.While the first robin is distracted by the chase, a blue jay arrives at the feeder and starts feeding.The interaction between the first and second robins is _______ competition, and that between the blue jay and the first robin is _______ competition.

A) intraspecific interference; interspecific interference
B) interspecific interference; intraspecific interference
C) intraspecific exploitation; interspecific exploitation
D) interspecific interference; intraspecific exploitation
E) intraspecific interference; interspecific exploitation

Question 73

The sea otter acts as a keystone species in the kelp (giant seaweed) forests of the ocean in the Pacific Northwest.Sea otters feed on sea urchins, which in turn feed on kelp.Crabs, snails, and geese also depend on kelp for food, and many types of fish use the kelp to hide from predators.Sea otter populations are declining in some areas because of increased predation by orca whales.What effect will the decline in sea otters likely have on the kelp community?

A) Little effect, since otters can be easily replaced by other predators.
B) Sea urchin populations will increase, and kelp populations will increase to provide more food for them.
C) Community diversity will increase, as prey species are no longer threatened by sea otters.
D) Community diversity will decrease as sea urchins overpopulate and overexploit kelp.
E) Sea urchins will overexploit kelp, thinning the habitat and providing room for more fish and invertebrates to move in.

Question 74

Some types of pine trees are attacked and fed on by pine bark beetles.As the beetles feed, they girdle the trees, destroying the phloem layer and killing the trees.Pine bark beetles are also associated with the blue stain fungus, which grows in their frass (feces).As they attack the trees, the beetles also inject the fungus.The fungal hyphae grow into the tree and follow its xylem cells, blocking the flow of xylem and causing rapid tree death.This information suggests that the relationship between the pine bark beetle and fungus is _______, while the relationship between the beetle and the pine tree is _______.

A) mutualism; parasitism
B) mutualism; commensalism
C) commensalism; parasitism
D) commensalism; herbivory
E) parasitism; parasitism

Question 75

Two species of barnacles, stellate and rock barnacles, occupy the rocky intertidal zone of the Scottish coast and illustrate factors that can determine species distribution in a community.Larvae of both species settle throughout the intertidal zone, but adult barnacles occupy specific zones.The smaller stellate barnacle lives only in higher zones, where the environment dries out between high tides.The larger, faster-reproducing rock barnacle lives only at lower zones.If rock barnacles were entirely removed from this community, what would most likely happen to the population of stellate barnacles?

A) They would go extinct.
B) They would leave the community.
C) There would be little or no change in their population.
D) They would expand their range to include both the low and high areas.
E) They would remain at high levels, and their population would increase.

Question 76

When two Appalachian salamander species occur in separate habitats, they have the same morphological characteristics.However, when they occur in the same habitat, one species has a faster-closing jaw, which enables it to feed on larger prey.The other has a slower, stronger jaw that accommodates smaller prey.This situation represents a form of _______, which has led to _______.

A) intraspecific competition; character displacement
B) interspecific competition; character displacement
C) exploitation competition; resource limitation
D) exploitation competition; competitive exclusion
E) interference competition; competitive exclusion

Question 77

Two species of barnacles, stellate and rock barnacles, occupy the rocky intertidal zone of the Scottish coast and illustrate factors that can determine species distribution in a community.Larvae of both species settle throughout the intertidal zone, but adult barnacles occupy specific zones.The smaller stellate barnacle lives only in higher zones, where the environment dries out between high tides.The larger, faster-reproducing rock barnacle lives only at lower zones.In general, the intertidal zonation seen in the barnacles is due to

A) parasitism and predation.
B) competitive interactions and predation.
C) susceptibility to abiotic conditions and parasitism.
D) predation and differential susceptibility to abiotic conditions.
E) competitive interactions and differential susceptibility to abiotic conditions.

Question 78

Which description is an example of character displacement?

A) Early in its growing season, scarlet gilia produces red flowers that attract hummingbirds; later in the season, it produces white flowers that attract hawk moths.
B) Large herbivores usually eat a wide variety of plants to minimize their exposure to the toxins of any one plant.
C) Finches in the Galápagos Islands are smaller on islands where bees are present, because bees compete with the finches for cactus nectar.
D) A species of butterfly eaten by bird predators evolves the color patterns of another butterfly species that is toxic to the predators.
E) Desert ants prevent honeypot ants from feeding, by dropping stones into the honeypot ants' nest openings.

Question 79

When sap-sucking leafhoppers feed on potato plants early in the growing season, they cause potato leaves to curl and lose chlorophyll.Later in the season, potato beetles that consume these damaged leaves show reduced growth and survival rates.This interaction is best described as _______ that is _______.

A) interference competition; asymmetrical
B) interference competition; symmetrical
C) exploitation competition; asymmetrical
D) exploitation competition; symmetrical
E) competitive exclusion; asymmetrical

Question 80

A mutualistic relationship will most likely lead to reciprocal adaptations when

A) the mutualism is asymmetrical.
B) one partner is an animal and the other is a plant.
C) both partners are plants.
D) both partners are animals.
E) increased benefits are gained by greater dependence on the partner.