Exam 55: Species Interactions

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?

In many areas of the Rocky Mountains, both squirrel and bird species extract and eat the pine seeds from cones of lodgepole pines.In a few areas, however, birds called red crossbills are the only consumers of the pine seeds.Where this one-on-one relationship occurs, both the birds and the pine trees have changed over generations.The crossbills have developed deeper, shorter, and straighter bills that are more efficient at extracting pine seeds, and the pines have developed larger, thicker scales on the cones that defend the seeds from extraction.This bird-tree interaction is an example of _______ due to _______.

At some water bird breeding colonies, the large quantities of excrement from the birds may result in the death of vegetation underneath the trees in which their nests are built.Which characteristic of the bird population would have the greatest effect on the amount of damage caused to the understory plants?

Most trees are dispersed by means of frugivores.If frugivore populations in an area declined because of disease, what would most likely happen to the tree species previously dispersed in this way?

In what way did the sea star, Pisaster ochraceus, act as a keystone species in the Robert Paine study of rocky shore communities in the Pacific Northwest?

Termites live on cellulose, mostly derived from the dead wood they chew.Protists in the gut provide enzymes that allow digestion of the wood.The termite gut provides a habitat for the protists.Classify this interaction in terms of the direction of its effect on both species.

Suggest conditions under which an animal might respond to competition by becoming a fugitive species.

The yucca and the yucca moth have an exclusive plant‒pollinator relationship.Which would represent a cost, rather than a benefit, of this relationship?

An herbivorous insect feeds on a plant, which produces a toxic chemical to protect itself.The insect develops a resistance to the chemical and continues to feed on the plant.The two species are undergoing _______.

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

When a soccer player guards her opponent and prevents her from receiving the ball, this is an example of _______ competition.When players from both teams rush toward a loose ball and the fastest player gains control of the ball, this is an example of _______ competition.

Taxonomically, most of the world's herbivores are _______.

The three species of bees that feed on the shin dagger agave in the American Southwest can be said to exhibit competitive coexistence because they

When a parasite first invades a host, it may be very damaging, even causing the host's death.Over many generations, the host-parasite relationship may evolve so that the parasite's effect on the host is much weaker.How would this evolution most likely affect the size of the parasite population?

Because they live outside their hosts, ticks are not only macroparasites but also _______.

In the following situations, which organism would be considered a microparasite?

When two populations of flour beetles, the red flour beetle and the confused flour beetle, occur together in the same bag of flour, the red flour beetle population usually increases and the confused flour beetle population dwindles to extinction.This type of outcome between species that use the same limited resource is called _______.

You find a series of related plants with chewed leaves growing in a defined area.You determine that this is the work of an herbivore specialist that feeds on a few closely related species and removes only a small percentage of the plant tissue without killing the plant.This herbivore is most likely

Refer to the graph below, showing population cycles of snowshoe hares and their predator, Canada lynx.Population numbers were collected when both populations were trapped for the fur trade. In the study of snowshoe hares and Canada lynx, this predator-prey interaction showed tightly controlled population cycles of approximately 10 years.The hares' numbers peaked, followed by peaks in lynx numbers approximately 2 to 3 years later.Assuming a cause-and-effect relationship between the two species, if lynx were removed from the community, the hare population would likely

Refer to the table below. Many flowers have characteristics that are attractive to more than one type of pollinator.Which of the flower types shown would be most likely to attract both beetles and butterflies as pollinators?