AP Bio U8L5 Ecological Interactions and Responses

Multiple Choice

A remora is a small fish that usually measures between one and three feet long. The remora interacts with leopard sharks by physically attaching itself to the leopard shark, usually on the belly or underside of the shark. The remora travels along with the leopard shark, without having to use its energy. Remoras also are able to eat the scraps of prey dropped by the sharp during feeding. The shark does not seem to benefit or be harmed by the relationship.

Which of the following identifies the type of symbiotic relationship between the remora and the shark based on the description above?

• mutualism

• commensalism

• parasitism

• predation

Multiple Choice

Lake trout are native to the Great Lakes, which are five lakes found on or near the border between Canada and the United States. At some point, the lake trout were introduced into Yellowstone Lake in Wyoming. Since being introduced to Yellowstone Lake, the lake trout have been competing with native cutthroat trout for resources.

Which of the following is a correct statement regarding competition for resources in a habitat?

Select all that apply.

• Organisms within the same habitat cannot occupy the same niche without competing directly for resources.

• Although the two organisms occupy the same niche, there are enough resources that the two species will not be affected.

• Resource partitioning may occur in which the two species will live in different areas in the ecosystem to avoid competition.

• When competition occurs, there will always be one species that changes their behavior to find a new food source.

Open Ended

Some birds, such as the brown-headed cowbirds, lay their eggs in the nests of other birds, including red-winged blackbirds. The blackbird parents raise the unrelated chicks and provide them with food that would otherwise be given to their biological offspring.

A researcher conducts an investigation to determine the type of symbiotic relationship between cowbirds and red-winged blackbirds specifically in an environment with no predators present. The researcher finds that nests containing only blackbirds were more likely to be successful than nests containing both cowbirds and blackbirds. The researcher defines a successful nest as a nest where at least one chick becomes an adult blackbird.

In some geographic locations, there are several species of nest predators that are present. Suppose that researchers find that while cowbird chicks are in the nest, they produce a smelly substance that deters nest predators. Suppose the researchers also find that the substance does not remain in the nest if cowbird chicks are removed.

(a) Describe the symbiotic relationship between the cowbird and the blackbird in an environment without predators.

(b) Identify the symbiotic relationship between the cowbird and the blackbird in the presence of predators.

(c) Adult male blackbirds produce a sound that acts as an alarm to other birds when a predator, such as a buzzard, is near. As a result, female birds respond in ways that may reduce the risk of predation, such as delaying visits to the nest. Identify the type of communication the male blackbird uses to communicate with female blackbirds.

Respond in 4 to 6 complete sentences.