Exam 28: Community Interactions

Two weed species live in the same patch of ground. One has deep roots to tap into ground water. The other has broad, shallow roots to take advantage of the frequent light rains that do not penetrate very deeply into the soil. This is an example of _.

Shade- tolerant plant species are generally found early in succession and are replaced by hardier, shade- intolerant species.

In the rain forests of Panama, scientists found a colony of tree- dwelling black ants where some individuals had red abdomens. When examined, the scientists determined that the ants with red abdomens were infected with roundworm eggs. Birds would prey on these ants, mistaking their red bellies for berries. In the interactions among the tree- dwelling black ants, the roundworms, and the birds, the ants are the _ for the roundworms.

In most environments, two or more organisms occupy identical niches.

Hawks that eat field mice are practicing mutualism.

Parasitism is a relationship in which one species benefits and the other does not benefit.

The productivity of an ecosystem usually _ _ through succession.

If similar species each occupy a smaller niche when they live together than they would if they lived alone, they are said to be

Kudzu is a vine that is native to Japan, but in the United States it is an exotic invader. In many parts of the United States, kudzu is rapidly expanding and outcompeting native species. Explain why kudzu is such an aggressive invader in the United States, but not in its native Japan.

An ecological niche

The concept that two species cannot occupy the same ecological niche at the same time is called

Parasites are generally smaller than their host.

In the Australian outback, emus (a relative of the ostrich) feeding in the open brush lands have coloration similar to the surrounding bushes. This is an example of

The spotted brown and black coats of mountain lion cubs make it difficult for predators to find them. This is known as .

Some toxic animals are brightly colored, as a means of warning others of their danger.

Aphids pierce the tissues of plants with their tubular mouthparts and suck out the phloem juices. Because this food is mostly sugar water with a low concentration of protein, the aphids have to process large volumes of it to obtain sufficient protein. Most of the excess sugar and water passes right through the aphids' digestive tracts and is defecated as "honeydew," which is actively sought out and eaten by some ants. The ants will even "milk" honeydew by stroking the aphids. In return, ants protect their aphids from predators, even going so far as taking them inside overnight. The relationship between the aphids and ants is called

When a community like the tallgrass prairie is maintained by recurring disturbances such as periodic fires set by Native Americans or by lightning, a community exists.

Two species that have a high degree of niche overlap will

Succession that begins on bare rock after glaciers have passed, or on newly formed volcanic islands, is

A storm strips an island in Lake Superior down to bare rock. The first organisms to recolonize the island are most likely