Exam 27: Community Interactions

Many brightly colored tree frogs are toxic. True or False?

Succession in small ponds and lakes is usually dependent on the input of ________ from outside the ecosystem.

A ________ feeds on another organism without killing it.

Organisms introduced as biocontrols for an invasive species can themselves become invasive. True or False?

Aphids pierce the tissues of plants with their tubular mouthparts and suck out the phloem juices. Since 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 are 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:

Over the past century, sagebrush has dramatically expanded its range over the Colorado Plateau's grasslands. This development has been attributed to the overgrazing of the area's grasses by cattle and sheep. This example indicates that:

The biologist who studies interactions at the community level investigates interactions among:

How do organisms help to cause the changes that result in their own replacement in succession?

The first community that forms on bare rock often has organisms such as:

Two species of buttercup are found in the same field in South Dakota, but they emerge at different times: One species emerges and flowers in early spring, and the other species does not emerge until late summer, after the first species has set seed. This is probably an example of:

An ecological niche:

Along many southern bayous you can see the remnants of old plantations that have been reclaimed by the forest and swamp in a process known as ________.

In a process called coevolution, two species exert natural selection pressures on each other. True or False?

Several ecology students were tracking the population ranges of two species of squirrels that live in the Cascade Range of Oregon. These students noted that when both species of squirrels were present in a region, species A could be found from sea level to about 900 feet above sea level, and species B could be found from about 900 feet to 1,500 feet above sea level. However, when species B was found alone, it had a range of about 500 feet to 1,500 feet above sea level. This is an example of:

Antelope and kangaroos are both herbivores that feed on grasses and brush. What would you expect to happen if someone set up a game farm and released both species into the same grassy plain?

A bat pollinates a plant while obtaining nectar from it. This behavior is an example of ________.

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

The process by which two interacting species act as agents of natural selection on one another is called:

In a mutualistic relationship, one species benefits and the other is harmed. True or False?

An example of ________ is when birds feed on parasitic insects they pick off the skin of large animals such as elephants or bison.