Ecology

Bacteria are important in the nitrogen cycle because they

• help convert nitrogen into a form that organisms can use.

• respire, returning carbon dioxide into the atmosphere.

• decay and eventually form fossil fuels.

• produce sugars that plants can use.

Which two processes in the carbon cycle are also parts of the oxygen cycle?

• combustion and respiration

• photosynthesis and decay

• combustion and decay

• photosynthesis and respiration

Which of the following can be both primary and secondary consumers?

• herbivores

• carnivores

• omnivores

• detritivores

Which of the following are biotic factors?

• soil, mushroom, tree

• soil, sunlight, river

• deer, mushroom, tree

• sunlight, river, deer

What is a detritivore?

• a producer that gets energy from sunlight

• a consumer that feeds on autotrophs

• a consumer that can feed on autotrophs or heterotrophs

• a decomposer that feeds on dead and decaying matter

Which process is part of the hydrologic cycle?

• nitrification

• transpiration

• decomposition

• sedimentation

If a keystone species is removed from an ecosystem,

• abiotic and biotic factors can be affected.

• only biotic factors can be affected.

• only abiotic factors can be affected.

• neither abiotic nor biotic factors can be affected.

What are two processes by which autotrophs make food?

• chemosynthesis and photosynthesis

• photosynthesis and respiration

• chemosynthesis and decomposition

• decomposition and combustion

A pyramid of numbers is used to show

• the distribution of biomass in an ecosystem.

• a network of feeding relationships.

• the distribution of organisms in an ecosystem.

• a chain of feeding relationships.

Which of the following best describes an ecosystem?

• all of the different species living in a given area

• all of the members of a single species living in a given area

• all of the biotic and abiotic factors in a given area

• all of the non-living factors that characterize a given area