Question 1

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

Accepted Answer

A) adding nitrogen-fixing bacteria to increase nitrogen availability 
B) using a bulldozer to regrade a strip mine to its original state 
C) reconfiguring the channel of a river to its natural river channel 
D) using a chromium-accumulating plant to extract soil chromium

Question 2

Which of the following is most correct regarding the activity of detritivores?

Accepted Answer

A) They synthesize the organic molecules that are used by the primary producers. 
B) They convert organic matter to inorganic,which is used by primary producers. 
C) They are primary producers that convert organic matter into inorganic detritus. 
D) They are autotrophs and heterotrophs that convert detritus to organic matter.

Question 3

How does phosphorus normally enter ecosystems?

Accepted Answer

A) from cellular respiration 
B) from photosynthesis 
C) from rock weathering 
D) from the atmosphere

Question 4

Please use the following information to answer the questions below.
A scientist conducts an experiment to quantify the effect of mycorrhizae and soil nitrogen levels on plant growth in a grassland.The experiment has four treatments: (1)mycorrhizae present and ambient levels of nitrogen, (2)mycorrhizae present and nitrogen added, (3)mycorrhizae absent and ambient levels of nitrogen,and (3)mycorrhizae absent and nitrogen added.After four weeks,the scientist removes the aboveground plant material for weighing.
  Figure 42.4
-What conclusion is best supported by Figure 42.4?

Accepted Answer

A) With ambient nitrogen levels,growth is limited even when mycorrhizae are present. 
B) Mycorrhizal associations result in the highest NPP levels regardless of nitrogen level. 
C) Interactions with mycorrhizae are always positive mutualistic fungal-plant interactions. 
D) Mycorrhizae should be added to restore successfully grasslands with high soil nitrogen.

Question 5

Consider the food chain grass → grasshopper → mouse → snake → hawk.How much of the chemical energy fixed by photosynthesis of the grass (100%)is available to the hawk?

Accepted Answer

A) 0.01% 
B) 0.1% 
C) 1% 
D) 10% 
E) 60%

Question 6

Scientists use trophic cycles to study the flow of matter in an ecosystem by observing feeding relationships between organisms.Which of the following statements is most correct regarding the terminology used in trophic cycles?

Accepted Answer

A) It is incorrect to refer to an omnivore as a heterotroph. 
B) The terms herbivore and autotroph mean the same thing. 
C) Labeling a carnivore as a heterotroph would be correct. 
D) Autotrophs can be correctly labeled as primary consumers. 
E) Primary producers would include the heterotrophic species.

Question 7

What is the maximum biomass of grasshoppers that could be supported by this square meter of tundra (i.e. ,if grasshoppers ate all the existing vegetation)?

Accepted Answer

A) 100 g 
B) 50 g 
C) 20 g 
D) 15 g

Question 8

Figure 42.2 Diagram of a food web (arrows represent energy flow and numbers represent species)
-If Figure 42.2 represents a terrestrial food web,the combined biomass of 3 + 4 would probably be

Accepted Answer

A) greater than the biomass of 1. 
B) less than the biomass of 8. 
C) greater than the biomass of 2. 
D) less than the biomass of 1 + 2. 
E) less than the biomass of 6.

Question 9

A porcupine eats 3000 J of plant material.Of this,2000 J are indigestible and are eliminated as feces,900 J are used in cellular respiration,and 100 J are used for growth and reproduction.What is the approximate production efficiency of this animal?

Accepted Answer

A) 0.03% 
B) 3% 
C) 10% 
D) 5% 
E) 67%

Question 10

Subtraction of which of the following will convert gross primary productivity into net primary productivity?

Accepted Answer

A) the energy contained in the standing crop 
B) the energy used by heterotrophs in respiration 
C) the energy used by autotrophs in respiration 
D) the energy fixed by photosynthetic processes 
E) the energy absorbed as solar or light energy

Question 11

To recycle nutrients,an ecosystem must have,at a minimum,

Accepted Answer

A) producers. 
B) producers and decomposers. 
C) producers,primary consumers,and decomposers. 
D) producers,primary consumers,secondary consumers,and decomposers. 
E) producers,primary consumers,secondary consumers,top carnivores,and decomposers.

Question 12

If you applied a fungicide to a cornfield,what would you expect to happen to the rate of decomposition and net ecosystem production (NEP)?

Accepted Answer

A) Both decomposition rate and NEP would decrease. 
B) Neither would change. 
C) Decomposition rate would increase,and NEP would decrease. 
D) Decomposition rate would decrease,and NEP would increase.

Question 13

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 per unit of area per unit of time [J/(m2.yr]. 
B) NPP is expressed in terms of carbon fixed by photosynthesis for an ecosystem. 
C) NPP represents the stored energy available to consumers in an ecosystem. 
D) NPP is the same as the total biomass of the photosynthetic autotrophs present. 
E) NPP shows the rate at which the total biomass is utilized by primary consumers.

Question 14

Which of the following organisms is correctly paired with its trophic level?

Accepted Answer

A) cyanobacterium-primary consumer 
B) grasshoppers-primary producers 
C) zooplankton-primary consumer 
D) detritivores-primary producers

Question 15

Why does a vegetarian leave a smaller ecological footprint than a person who eats meat?

Accepted Answer

A) Fewer farm animals are slaughtered for human consumption. 
B) There is an excess of plant biomass in all terrestrial ecosystems. 
C) Vegetarians need to ingest less chemical energy than omnivores. 
D) Vegetarians require less protein to sustain life than do omnivores. 
E) Eating meat is an inefficient way to utilize autotrophic productivity.

Question 16

What is the first step in the restoration of an extremely degraded ecosystem?

Accepted Answer

A) to restore the physical structure 
B) to restore the native species 
C) to remove competitive invasive species 
D) to identify the factors limiting producers 
E) to remove toxic pollutants

Question 17

If the total amount of energy from light converted into chemical energy in this square meter of tundra is 200 g,what is the amount of autotrophic respiration?

Accepted Answer

A) 200 g 
B) 100 g 
C) 85 g 
D) 15 g 
E) 0.5 g

Question 18

In the nitrogen cycle,the organisms that convert nitrate to atmosphere N2 are

Accepted Answer

A) detritivores. 
B) nitrifying bacteria. 
C) denitrifying bacteria. 
D) nitrogen-fixing bacteria. 
E) decomposers.

Question 19

What is the primary limiting factor for aquatic primary production?

Accepted Answer

A) water pressure 
B) lack of nutrients 
C) light availability 
D) primary consumers 
E) invasive organisms

Question 20

Nitrogen can be used by plants in the form of

Accepted Answer

A) nitrogen gas.  
B) nitrite ions. 
C) uric acid. 
D) ammonia. 
E) nitrate ions.

Exam 42: Ecosystems and Energy

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

Which of the following is most correct regarding the activity of detritivores?

How does phosphorus normally enter ecosystems?

Consider the food chain grass → grasshopper → mouse → snake → hawk.How much of the chemical energy fixed by photosynthesis of the grass (100%) is available to the hawk?

Scientists use trophic cycles to study the flow of matter in an ecosystem by observing feeding relationships between organisms.Which of the following statements is most correct regarding the terminology used in trophic cycles?

What is the maximum biomass of grasshoppers that could be supported by this square meter of tundra (i.e. ,if grasshoppers ate all the existing vegetation) ?

Figure 42.2 Diagram of a food web (arrows represent energy flow and numbers represent species) -If Figure 42.2 represents a terrestrial food web,the combined biomass of 3 + 4 would probably be