If Figure 42.2 represents a terrestrial food web, the combined biomass of C + D would
probably be
A) greater than the biomass of A.
B) less than the biomass of H.
C) greater than the biomass of B.
D) less than the biomass of A + B.
E) less than the biomass of F.

less than the biomass of A + B.

If Figure 42.2 represents a marine food web, the smallest organism might be
A) A.
B) F.
C) C.
D) I.
E) E.

A

In the diagram of the nitrogen cycle in Figure 42.3, which number represents nitrite (NO2)?
A) 1
B) 2
C) 3
D) 4

2

In the diagram of the nitrogen cycle in Figure 42.3, which number represents the ammonium
ion (NH4+)?
A) 1
B) 2
C) 3
D) 4

4

In the diagram of the nitrogen cycle in Figure 42.3, which number represents nitrogen-fixing
bacteria?
A) 5
B) 6
C) 7

5

In the diagram of the nitrogen cycle in Figure 42.3, which number represents nitrifying
bacteria?
A) 5
B) 6
C) 7

6

As big as it is, the ocean is nutrient-limited. If you wanted to investigate this, one reasonable
approach would be to
A) follow whale migrations in order to determine where most nutrients are located.
B) observe Antarctic Ocean productivity from year to year to see if it changes.
C) experimentally enrich some areas of the ocean and compare their productivity to that of
untreated areas.
D) compare nutrient concentrations between the photic zone and the benthic zone in various
marine locations.
E) contrast nutrient uptake by autotrophs in marine locations that are different temperatures.

experimentally enrich some areas of the ocean and compare their productivity to that of
untreated areas.

A porcupine eats 3,000 J of plant material. Of this, 2,100 J is indigestible and is eliminated as
feces, 800 J are used in cellular respiration, and 100 J are used for growth and reproduction.
What is the approximate production efficiency of this animal?
A) 0.03%
B) 3%
C) 11%
D) 27%
E) 33%

3%

Suppose you are studying the nitrogen cycling in a pond ecosystem over the course of a
month. While you are collecting data, a flock of 100 Canada geese lands and spends the night
during a fall migration. What could you do to eliminate error in your study as a result of this
event?
A) Find out how much nitrogen is consumed in plant material by a Canada goose over about a
12-hour period, multiply this number by 100, and add that amount to the total nitrogen in the
ecosystem.
B) Find out how much nitrogen is eliminated by a Canada goose over about a 12-hour period,
multiply this number by 100, and subtract that amount from the total nitrogen in the ecosystem.
C) Find out how much nitrogen is consumed and eliminated by a Canada goose over about a 12-
hour period and multiply this number by 100; enter this +/- value into the nitrogen budget of the
ecosystem.
D) Do nothing. The Canada geese visitation to the lake would have negligible impact on the
nitrogen budget of the pond.
E) Put a net over the pond so that no more migrating flocks can land on the pond and alter the
nitrogen balance of the pond.

Find out how much nitrogen is consumed and eliminated by a Canada goose over about a 12-
hour period and multiply this number by 100; enter this +/- value into the nitrogen budget of the
ecosystem.

Which of the following organisms is incorrectly paired with its trophic level?
A) cyanobacterium—primary producer
B) grasshopper—primary consumer
C) zooplankton—primary producer
D) eagle—tertiary consumer
E) fungus—detritivore

zooplankton—primary producer

Which of these ecosystems has the lowest net primary production per square meter?
A) a salt marsh
B) an open ocean
C) a coral reef
D) a grassland
E) a tropical rain forest

an open ocean

The discipline that applies ecological principles to returning degraded ecosystems to a more
natural state is known as
A) population viability analysis.
B) landscape ecology.
C) conservation ecology.
D) restoration ecology.
E) resource conservation.

restoration ecology.

Nitrifying bacteria participate in the nitrogen cycle mainly by
A) converting nitrogen gas to ammonia.
B) releasing ammonium from organic compounds, thus returning it to the soil.
C) converting ammonia to nitrogen gas, which returns to the atmosphere.
D) converting ammonium to nitrate, which plants absorb.
E) incorporating nitrogen into amino acids and organic compounds.

converting ammonium to nitrate, which plants absorb.

Which of the following has the greatest effect on the rate of chemical cycling in an
ecosystem?
A) the ecosystem’s rate of primary production
B) the production efficiency of the ecosystem’s consumers
C) the rate of decomposition in the ecosystem
D) the trophic efficiency of the ecosystem
E) the location of the nutrient reservoirs in the ecosystem

the rate of decomposition in the ecosystem

The Hubbard Brook watershed deforestation experiment yielded all of the following results
except:
A) Most minerals were recycled within a forest ecosystem.
B) The flow of minerals out of a natural watershed was offset by minerals flowing in.
C) Deforestation increased water runoff.
D) The nitrate concentration in waters draining the deforested area became dangerously high.
E) Calcium levels remained high in the soil of deforested areas.

Calcium levels remained high in the soil of deforested areas.

Which of the following would be considered an example of bioremediation?
A) adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen
availability
B) using a bulldozer to regrade a strip mine
C) dredging a river bottom to remove contaminated sediments
D) reconfiguring the channel of a river
E) adding seeds of a chromium-accumulating plant to soil contaminated by chromium

adding seeds of a chromium-accumulating plant to soil contaminated by chromium

If you applied a fungicide to a cornfield, what would you expect to happen to the rate of
decomposition and net ecosystem production (NEP)?
A) Both decomposition rate and NEP would decrease.
B) Both decomposition rate and NEP would increase.
C) Neither would change.
D) Decomposition rate would increase and NEP would decrease.
E) Decomposition rate would decrease and NEP would increase.

Decomposition rate would decrease and NEP would increase.