Question 1

Trophic efficiency is

Accepted Answer

A)   the ratio of net secondary production to assimilation of primary production.
B)   the percentage of production transferred from one trophic level to the next.
C)   a measure of how nutrients are cycled from one trophic level to the next.
D)   usually greater than production efficiencies.
E)   about 90% in most ecosystems.F) B) and C)
G) None of the above

Question 2

As big as it is, the ocean is nutrient-limited. If you wanted to investigate this, one reasonable approach would be to

Accepted Answer

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.F) C) and E)
G) D) and E)

Question 3

How is net ecosystem production (NEP)  typically estimated in ecosystems?

Accepted Answer

A)   the ratio of producers to consumers
B)   the amount of heat energy released by the ecosystem
C)   the net flux of CO2 or O2 in or out of an ecosystem
D)   the rate of decomposition by detritivores
E)   the annual total of incoming solar radiation per unit of areaF) C) and D)
G) All of the above

Question 4

Which of the following terms encompasses all of the others?

Accepted Answer

A)   heterotrophs
B)   herbivores
C)   carnivores
D)   primary consumers
E)   secondary consumersF) C) and D)
G) B) and C)

Question 5

The major role of detrivores in ecosystems is to

Accepted Answer

A)   provide a nutritional resource for heterotrophs.
B)   recycle chemical nutrients to a form capable of being used by autotrophs.
C)   prevent the buildup of the inorganic remains of organisms, feces, and so on.
D)   return energy lost to the ecosystem by other organisms.E) A) and D)
F) B) and C)

Question 6

Why is net primary production (NPP)  a more useful measurement to an ecosystem ecologist than gross primary production (GPP) ?

Accepted Answer

A)   NPP can be expressed in energy/unit of area/unit of time.
B)   NPP can be expressed in terms of carbon fixed by photosynthesis for an entire ecosystem.
C)   NPP represents the stored chemical energy that will be available to consumers in the ecosystem.
D)   NPP is the same as the standing crop.
E)   NPP shows the rate at which the standing crop is utilized by consumers.F) All of the above
G) A) and E)

Question 7

Figure 42.1 Food web for a particular terrestrial ecosystem (arrows represent energy flow and letters represent species) 
-Examine the food web for a particular terrestrial ecosystem in Figure 42.1. Species C is toxic to predators. Which species is most likely to benefit from being a mimic of C?

Accepted Answer

A)   A
B)   B
C)   C
D)   D
E)   EF) A) and E)
G) A) and B)

Question 8

Which of the following would be considered an example of bioremediation?

Accepted Answer

A)   using a bulldozer to reshape the land around an abandoned strip mine to change erosion patterns
B)   dredging a river bottom to remove contaminated sediments
C)   reconfiguring the channel of a river to increase the flow of water down a river
D)   raising chromium-accumulating plants to extract chromium from contaminated soil
E)   selectively harvesting younger trees in a forest to leave older trees for woodpecker nesting habitatF) A) and B)
G) A) and E)

Question 9

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?

Accepted Answer

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.F) None of the above
G) C) and D)

Question 10

Corn production in many states of the Midwest is limited by nitrogen levels in the soil. Some farmers reduce the need to apply expensive anhydrous ammonia to their fields by rotating corn crops with nitrogen-fixing soybean crops. Using soybeans to add nitrogen to soils is an example of

Accepted Answer

A)   biological augmentation.
B)   the biomass pyramid.
C)   promoting leaching efficiency.
D)   bioremediation.
E)   trophic efficiency.F) B) and C)
G) B) and D)

Question 11

What is the first step in ecosystem restoration?

Accepted Answer

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 pollutantsF) C) and D)
G) A) and D)

Question 12

Figure 42.2 Diagram of a food web (arrows represent energy flow and letters represent species) 
-If Figure 42.2 represents a terrestrial food web, the combined biomass of C + D would probably be

Accepted Answer

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.F) C) and D)
G) B) and E)

Question 13

Aquatic primary productivity is most limited by which of the following?

Accepted Answer

A)   light and nutrient availability
B)   predation by primary consumers
C)   increased pressure with depth
D)   pollution
E)   temperatureF) B) and D)
G) A) and B)

Question 14

How does phosphorus normally enter ecosystems?

Accepted Answer

A)   cellular respiration
B)   photosynthesis
C)   rock weathering
D)   vulcanism
E)   atmospheric phosphorous gasF) C) and D)
G) A) and B)

Question 15

Figure 42.3
-In the diagram of the nitrogen cycle in Figure 42.3, which number represents nitrite (NO2) ?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) C) and D)
F) All of the above

Question 16

Nitrogen is available to plants mostly in the form of

Accepted Answer

A)   N2 in the atmosphere.
B)   nitrite ions in the soil.
C)   uric acid from animal excretions.
D)   nucleic acids from decomposing plants and animals.
E)   nitrate and ammonium ions in the soil.F) A) and E)
G) A) and B)

Question 17

What is the primary limiting factor for aquatic productivity?

Accepted Answer

A)   pressure
B)   lack of nutrients
C)   light availability
D)   herbivores
E)   competitionF) B) and D)
G) C) and E)

Question 18

What is the goal of restoration ecology?

Accepted Answer

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 ecosystemsF) A) and E)
G) C) and E)

Question 19

Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?

Accepted Answer

A)   Many primary and higher-order consumers are opportunistic feeders.
B)   Decomposers compete with higher-order consumers for nutrients and energy.
C)   Nutrient cycles involve both abiotic and biotic components of ecosystems.
D)   Nutrient cycling rates tend to be limited by decomposition.
E)   Energy transfer between trophic levels is almost always less than 20% efficient.F) A) and E)
G) A) and B)

Question 20

Which of the following is true of detritivores?

Accepted Answer

A)   They recycle chemical elements directly back to primary consumers.
B)   They synthesize organic molecules that are used by primary producers.
C)   They convert organic materials from all trophic levels to inorganic compounds usable by primary producers.
D)   They secrete enzymes that convert the organic molecules of detritus into CO2 and H2O.
E)   Some species are autotrophic, whereas others are heterotrophic.F) C) and E)
G) A) and D)

Exam 42: Ecosystems and Energy

Aquatic primary productivity is most limited by which of the following?

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How is net ecosystem production (NEP) typically estimated in ecosystems?

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Figure 42.1 Food web for a particular terrestrial ecosystem (arrows represent energy flow and letters represent species) -Examine the food web for a particular terrestrial ecosystem in Figure 42.1. Species C is toxic to predators. Which species is most likely to benefit from being a mimic of C?

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Figure 42.2 Diagram of a food web (arrows represent energy flow and letters represent species) -If Figure 42.2 represents a terrestrial food web, the combined biomass of C + D would probably be

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Figure 42.3 -In the diagram of the nitrogen cycle in Figure 42.3, which number represents nitrite (NO2) ?

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Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?

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The major role of detrivores in ecosystems is to

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Corn production in many states of the Midwest is limited by nitrogen levels in the soil. Some farmers reduce the need to apply expensive anhydrous ammonia to their fields by rotating corn crops with nitrogen-fixing soybean crops. Using soybeans to add nitrogen to soils is an example of

Correct AnswerverifiedShow Answer

What is the goal of restoration ecology?

Correct AnswerverifiedShow Answer

What is the primary limiting factor for aquatic productivity?

Correct AnswerverifiedShow Answer

As big as it is, the ocean is nutrient-limited. If you wanted to investigate this, one reasonable approach would be to

Correct AnswerverifiedShow Answer

How does phosphorus normally enter ecosystems?

Correct AnswerverifiedShow Answer

What is the first step in ecosystem restoration?

Correct AnswerverifiedShow Answer

Which of the following terms encompasses all of the others?

Correct AnswerverifiedShow Answer

Which of the following is true of detritivores?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Nitrogen is available to plants mostly in the form of

Correct AnswerverifiedShow Answer

Trophic efficiency is

Correct AnswerverifiedShow Answer

Why is net primary production (NPP) a more useful measurement to an ecosystem ecologist than gross primary production (GPP) ?

Correct AnswerverifiedShow Answer

Which of the following would be considered an example of bioremediation?

Correct AnswerverifiedShow Answer

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