13.2: Biotic and Abiotic Factors

Which of the following is an example of a biotic factor in an ecosystem?

• sunlight

• stream

• tree

• rock

Wind is considered to be an abiotic factor because it

• is not related to biodiversity

• is a nonliving thing

• is in equilibrium

• is not in any ecosystem

A rain forest has a high level of biodiversity because it has

• many abiotic factors

• some endangered species

• few connections between living things

• a wide variety of living things

A keystone species is a species that

• goes unnoticed if its numbers decrease

• alters an area by building bridges and dams

• leads to a decrease in an area's biodiversity

• has an unusually large impact on its ecosystem

Beavers are sometimes trapped for their fur. What could be one effect of increased trapping of beavers in an area?

• biodiversity among the area's fish would increase

• the number of herons and kingfishers would decrease

• there would be more nesting areas for waterfowl

• more trees would be cut down