chapter 20

Producers are at which trophic level?

• first

• second

• third

• fourth or higher

• the level varies with different ecosystems

energy flow in an ecosystem is:

• cyclical

• one-way

• two-way

• reversible under different conditions

• exponential

most energy within an ecosystem is lost:

• when organisms disperse

• when organisms die

• as a result of metabolism

• by organisms at the top of the food web

• by decomposers

Biological magnification can be defined as the:

• Concentration of a chemical in organisms increasing as the pollutant moves up a food chain

• Energy transfer increasing as it moves up a food chain

• Fixation of nutrients from the atmosphere

• Entrance into the biological portion of a biogeochemical cycle

• Increase in food web members in biologically diverse ecosystems

What cycle includes movement of a nutrient from rocks and sediments, waters, and/or atmosphere into and out of food webs?

• sedimentary

• nitrogen

• water

• biogeochemical

• carbon

Four of the five answers are correct statements about materials in biogeochemical cycles. Select the exception.

• They pass from environmental reservoirs to living organisms.

• They move slower than elements in living systems move

• They eventually move from living organisms back into environmental reservoirs

• They may include rocks and sediments, waters, and atmosphere reservoirs

• They are unidirectional, moving from the environment to living organisms

Most fresh water exists as:

• ice

• soil water

• aquifer water

• surface water (lakes,rivers)

• atmosphere

Producers fix carbon from _____ through the process of _____.

• Carbon dioxide; metabolism

• Carbon dioxide; cellular respiration

• Carbon dioxide; photosynthesis

• Oxygen; photosynthesis

• Oxygen; cellular respiration

The greatest concentration of nitrogen on the planet Earth is found in:

• Living organisms, including bacteria

• The atmosphere

• Soil materials

• Fossil fuels

• Oceans

How does phosphorus enter the biological portion of the cycle?

• Land plants take up dissolved phosphate from the soil water.

• Bacteria fox phosphate from the atmosphere

• Consumers eat phosphate containing soil

• Bacteria fix phosphate from water

• Erosion of rocks moves phosphate into water, which consumers drink.