Exam 55: Species Interactions

A fallen western hemlock becomes a "nurse log" on the forest floor, providing a raised substrate that keeps seedlings off the ground.Seedlings growing in the log survive better than those growing on the forest floor.Which of the following statements does not describe a mutualism or benefit that likely contributes to the tree seedlings' improved survival?

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?

Explain the concept of symbiosis, and give examples of both positive and negative symbioses.

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

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 species of brightly colored herbivorous insect enters a new environment.Which factor found in the new environment is most likely to lead over time to a situation involving coevolution?

Anemonefish live inside sea anemones and acclimate, so they are unaffected by anemone stings.They avoid predators and may steal food brought in by the anemone's tentacles.Their feces may provide nitrogen to the anemone, but this effect is not clear.Why might this interaction be hard to classify, and what classifications might it fit into?

Refer to the table below showing the results of a greenhouse experiment.Sunflowers and corn plants are grown in 6-inch pots in treatments of varying plant densities and plant combinations.There are ten pots per treatment.All pots contain the same amount of potting soil and receive the same amount of water and sunlight.After 2 months, the heights of the plants in each pot are measured and averaged. Describe the effects of interspecific competition in the two species.

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

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?

Which type of organism is most typical of herbivores?

Which prey defense represents a chemical defense but not a warning signal?

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?

Refer to the graph below showing the result of sea star removal on community structure. The graph suggests that the predatory sea star acts as a _______ species in this community.

Which statement is a correct comparison of predators and parasites?

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?

Caterpillars feed on plant leaves.Some plants contain compounds that, when mixed with the saliva of particular caterpillar species, create an odor that attracts parasitoid wasps.Unlike true parasites, parasitoids like these wasps kill their hosts (caterpillars), often laying their eggs within the caterpillar carcasses.The relationship between plant and wasp could be considered _______; the relationship between wasp and caterpillar is _______.

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

The geographic distributions of wolves and coyotes often do not overlap.A study of wolves and coyotes in an area where they do overlap found that the two species minimized competition by differential use of food resources.Wolves preyed primarily on elk and a few deer, whereas coyotes preyed mostly on deer and rarely on young elk.Coyotes also scavenged abandoned wolf kills.Wolf and coyote behavior illustrates which type of competition?

Which feature is not an adaptation usually associated with predators?