46) Which of the following locations is the reservoir for nitrogen in the nitrogen cycle?
A) atmosphere
B) sedimentary bedrock
C) fossilized plant and animal remains (coal, oil, and natural gas)
D) plant and animal biomass
E) soil
47) Which of the following locations is the reservoir for carbon for the carbon cycle?
A) atmosphere
B) sediments and sedimentary rocks
C) fossilized plant and animal remains (coal, oil, and natural gas)
D) plant and animal biomass
E) all of the above
48) In the nitrogen cycle, the bacteria that replenish the atmosphere with N2 are
A) Rhizobium bacteria.
B) nitrifying bacteria.
C) denitrifying bacteria.
D) methanogenic protozoans.
E) nitrogen-fixing bacteria.
49) How does phosphorus normally enter ecosystems?
A) cellular respiration
B) photosynthesis
C) rock weathering
D) vulcanism
E) atmospheric phosphorous gas
50) Which of the following is an example of a local biogeochemical cycle?
A) O2 released by oak trees in a forest
B) CO2 absorbed by phytoplankton in the open ocean
C) excess NO3– converted to N2 by denitrifying soil bacteria
D) phosphorous being absorbed from the soil by a corn plant
E) organic carbon remains of a leaf being converted to CO2 by a fungus
51) Which of the following statements is correct about biogeochemical cycling?
A) The phosphorus cycle involves the recycling of atmospheric phosphorus.
B) The phosphorus cycle involves the weathering of rocks.
C) The carbon cycle is a localized cycle that primarily involves the burning of fossil fuels.
D) The carbon cycle has maintained a constant atmospheric concentration of CO2 for the past million
years.
E) The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic
components of the ecosystem.
52) Which of the following properly links the nutrient to its reservoir?
A) nitrogen ionic nitrogen in the soil
B) water atmospheric water vapor
C) carbon dissolved CO2 in aquatic ecosystems
D) phosphorous sedimentary rocks
E) All of the options are correct.
53) In terms of nutrient cycling, why does timber harvesting in a temperate forest cause less ecological
devastation than timber harvesting in tropical rain forests?
A) Trees are generally less numerous in temperate forests, so fewer nutrients will be removed from the
temperate forest ecosystem during a harvest.
B) Temperate forest tree species require fewer nutrients to survive than their tropical counterpart
species, so a harvest removes fewer nutrients from the temperate ecosystem.
C) The warmer temperatures in the tropics influence rain forest species to assimilate nutrients more
slowly, so tropical nutrient absorption is much slower than in temperate forests.
D) There are far fewer decomposers in tropical rain forests, so turning organic matter into usable
nutrients is a slower process than in temperate forest ecosystems.
E) Typical harvests remove up to 75% of the nutrients in the woody trunks of tropical rain forest trees,
leaving nutrient-impoverished soils behind.
54) Why do logged tropical rain forest soils typically have nutrient-poor soils?
A) Tropical bedrock contains little phosphorous.
B) Logging results in soil temperatures that are lethal to nitrogen-fixing bacteria.
C) Most of the nutrients in the ecosystem are removed in the harvested timber.
D) The cation exchange capacity of the soil is reversed as a result of logging.
E) Nutrients evaporate easily into the atmosphere in the post-logged forest.
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55) What is the first step in ecosystem restoration?
A) to restore the physical structure
B) to restore native species that have been extirpated due to disturbance
C) to remove competitive invasive species
D) to identify the limiting factors of the producers
E) to remove toxic pollutants
56) What is the goal of restoration ecology?
A) to replace a ruined ecosystem with a more suitable ecosystem for that area
B) to speed up the restoration of a degraded ecosystem
C) to completely restore a disturbed ecosystem to its former undisturbed state
D) to prevent further degradation by protecting an area with park status
E) to manage competition between species in human-altered ecosystems
57) Which of the following statements is true?
A) An ecosystem’s trophic structure determines the rate at which energy cycles within the system.
B) At any point in time, it is impossible for consumers to outnumber producers in an ecosystem.
C) Chemoautotrophic prokaryotes near deep-sea vents are primary producers.
D) There has been a well-documented increase in atmospheric nitrogen over the past several decades.
E) The reservoir of ecosystem phosphorous is the atmosphere.
58) In a typical grassland community, which of the following has the smallest biomass?
A) hawk
B) snake
C) shrew
D) grasshopper
E) grass
59) In a typical grassland community, which of the following is the primary consumer?
A) hawk
B) snake
C) shrew
D) grasshopper
E) grass
60) When levels of CO2 are experimentally increased in a typical grassland community, C3 plants
generally respond with a greater increase in productivity than C4 plants. This is because
A) C3 plants are more efficient in their use of CO2.
B) C3 plants are able to obtain the same amount of CO2 by keeping their stomata open for shorter
periods of time.
C) C4 plants don’t use CO2 as their source of carbon.
D) C3 plants are more limited by CO2 availability because they lack mechanisms to prevent
transpirational water loss.
E) C3 plants have special adaptations for CO2 uptake, such as larger stomata.
Art Questions
Food web for a particular terrestrial ecosystem (arrows represent energy flow and letters
represent species)
61) Examine this food web for a particular terrestrial ecosystem. Which species is autotrophic?
A) A
B) B
C) C
D) D
E) E
62) Examine this food web for a particular terrestrial ecosystem. Which species is most likely a
decomposer on this food web?
A) A
B) B
C) C
D) D
E) E
16
63) Examine this food web for a particular terrestrial ecosystem. Species C is toxic to predators. Which
species is most likely to benefit from being a mimic of C?
A) A
B) B
C) C
D) D
E) E
64) Examine this food web for a particular terrestrial ecosystem. Which pair of species could be
omnivores?
A) A and B
B) A and D
C) B and C
D) C and D
E) C and E
Diagram of a food web (arrows represent energy flow and letters represent species)
65) If the figure above 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 E.
66) If the figure above represents a marine food web, the smallest organism might be
A) A.
B) F.
C) C.
D) I.
E) E.
67) On the diagram of the nitrogen cycle, which number represents nitrite (NO2)?
A) 1
B) 2
C) 3
D) 4
68) On the diagram of the nitrogen cycle, which number represents ammonia (NH4+)?
A) 1
B) 2
C) 3
D) 4
69) On the diagram of the nitrogen cycle, which number represents nitrogen-fixing bacteria?
A) 5
B) 6
C) 7
70) On the diagram of the nitrogen cycle, which number represents nitrifying bacteria?
A) 5
B) 6
C) 7
Scenario Questions
71) 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.
72) 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.
73) 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) 10%
D) 27%
E) 33%
End-of-Chapter Questions
The following questions are from the end-of–chapter “Test Your Understanding” section in Chapter 55
of the textbook.
74) 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
75) 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
76) 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.
77) 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.
78) 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
79) 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.
80) 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
81) 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.