A keystone species can be defined as any species whose ____ a community would bring about significant change in it.

There are three principal types of biodiversity: ____, ____, and ____.

A habitat is the ____ in which a species can ____, while a niche can be thought of as an organism’s ____.

The filmmakers in the movie King Kong land on the imaginary Skull Island, which is the home not only of the giant ape Kong but of a host of meat-eating dinosaurs as well. Setting aside the impossibility of an ape as big as Kong, from an ecological perspective, why could a real Skull Island never have existed, even when dinosaurs roamed the Earth?

Carbon (select all that apply):

a. is an element

b. is a nutrient.

c. moves into the living world through animals.

d. moves into the atmosphere through the work of decomposers.

e. makes up about 21 percent of Earth’s atmosphere.

Bacteria and fungi are vitally important to the living world. If all bacteria and fungi were somehow instantly eliminated, almost no life-forms would survive for long. This is so because of the role bacteria and fungi play in ecological processes. Can you name two of these processes?

Nitrogen (select all that apply):

a. is not a nutrient.

b. is transferred into the living world in nature through the actions of plants.

c. is transferred into the living world in nature through the actions of bacteria.

d. has been manufactured by humans since the early twentieth century.

e. exists in such low concentrations in some coastal waters that “dead zones” are the result.

Tundra and desert are in some ways more fragile biomes than are grasslands or forests. Why should this be so?

There is a simple food chain in an eastern Oregon desert grassland: Mice are consumed by several species of snakes, which are consumed by hawks. The hawk is a __________ and occupies the __________ trophic level in this ecosystem.

a. tertiary consumer; fourth

b. secondary consumer; fourth

c. tertiary consumer; third

d. secondary consumer; third

e. primary consumer; third

A dung beetle (can you guess what it eats?) is an example of a:

a. detritivore.

b. omnivore.

c. carnivore.

d. herbivore.

e. producer.