Question 1

What is the primary limiting factor for aquatic productivity?

Accepted Answer

A)  pressure 
B)  lack of nutrients 
C)  light availability 
D)  herbivores 
E)  competition 
A)  pressure 
B)  lack of nutrients 
C)  light availability 
D)  herbivores 
E)  competition

Question 2

Which of the following is true of detrivores?

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, while others are heterotrophic. 
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, while others are heterotrophic.

Question 3

Which of the following statements is true?

Accepted Answer

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. 
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.

Question 4

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

Accepted Answer

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. 
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.

Question 5

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)  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. 
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.

Question 6

Many homeowners mow their lawns during the summer and collect the clippings, which are then hauled to the local landfill. Which of the following actions would most benefit the suburban ecosystem?

Accepted Answer

A)  Allow sheep to graze the lawn and then collect the sheep's feces to be delivered to the landfill. 
B)  Collect the lawn clippings and burn them. 
C)  Collect the lawn clippings and add them to a compost pile, don't collect the clippings and let them decompose into the lawn, or apply composted clippings to the lawn. 
D)  Collect the clippings and wash them into the nearest storm sewer that feeds into the local lake. 
E)  Dig up the lawn and cover the yard with asphalt. 
A)  Allow sheep to graze the lawn and then collect the sheep's feces to be delivered to the landfill. 
B)  Collect the lawn clippings and burn them. 
C)  Collect the lawn clippings and add them to a compost pile, don't collect the clippings and let them decompose into the lawn, or apply composted clippings to the lawn. 
D)  Collect the clippings and wash them into the nearest storm sewer that feeds into the local lake. 
E)  Dig up the lawn and cover the yard with asphalt.

Question 7

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 is 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. 
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 is 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.

Question 8

Nitrogen is available to plants only in the form of

Accepted Answer

A)  N₂ in the atmosphere. 
B)  nitrite ions in the soil. 
C)  uric acid from animal excretions. 
D)  amino acids from decomposing plant and animal proteins. 
E)  nitrate ions in the soil. 
A)  N₂ in the atmosphere. 
B)  nitrite ions in the soil. 
C)  uric acid from animal excretions. 
D)  amino acids from decomposing plant and animal proteins. 
E)  nitrate ions in the soil.

Question 9

Which of these ecosystems accounts for the largest amount of Earth's net primary productivity?

Accepted Answer

A)  tundra 
B)  savanna 
C)  salt marsh 
D)  open ocean 
E)  tropical rain forest 
A)  tundra 
B)  savanna 
C)  salt marsh 
D)  open ocean 
E)  tropical rain forest

Question 10

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 organic remains of organisms, feces, and so on. 
D)  return energy lost to the ecosystem by other organisms. 
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 organic remains of organisms, feces, and so on. 
D)  return energy lost to the ecosystem by other organisms.

Question 11

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

Question 12

In terms of nutrient cycling, why does timber harvesting in a temperate forest cause less ecological devastation than timber harvesting in tropical rain forests?

Accepted Answer

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. 
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.

Question 13

A 3-hectare lake in the American Midwest suddenly has succumbed to an algal bloom. What is the likely cause of eutrophication in freshwater ecosystems, such as this one?

Accepted Answer

A)  increased solar radiation 
B)  introduction of non-native tertiary consumer fish 
C)  nutrient runoff 
D)  accidental introduction of a prolific culture of algae 
E)  iron dust blowing into the lake 
A)  increased solar radiation 
B)  introduction of non-native tertiary consumer fish 
C)  nutrient runoff 
D)  accidental introduction of a prolific culture of algae 
E)  iron dust blowing into the lake

Question 14

Which of the following is an example of a local biogeochemical cycle?

Accepted Answer

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 
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

Question 15

Food web for a particular terrestrial ecosystem (arrows represent energy flow and letters represent species)
-Examine this food web for a particular terrestrial ecosystem. Which pair of species could be omnivores?

Accepted Answer

A)  A and B 
B)  A and D 
C)  B and C 
D)  C and D 
E)  C and E 
A)  A and B 
B)  A and D 
C)  B and C 
D)  C and D 
E)  C and E

Question 16

How is it that satellites can detect differences in primary productivity on Earth?

Accepted Answer

A)  Photosynthetic organisms absorb more visible light in the 350-750 wavelengths. 
B)  Satellite instruments can detect reflectance patterns of the photosynthetic organisms of different ecosystems. 
C)  Sensitive satellite instruments can measure the amount of NADPH produced in the summative light reactions of different ecosystems. 
D)  Satellites detect differences by comparing the wavelengths of light captured and reflected by photoautotrophs to the amount of light reaching different ecosystems. 
E)  Satellites detect differences by measuring the amount of water vapor emitted by transpiring producers. 
A)  Photosynthetic organisms absorb more visible light in the 350-750 wavelengths. 
B)  Satellite instruments can detect reflectance patterns of the photosynthetic organisms of different ecosystems. 
C)  Sensitive satellite instruments can measure the amount of NADPH produced in the summative light reactions of different ecosystems. 
D)  Satellites detect differences by comparing the wavelengths of light captured and reflected by photoautotrophs to the amount of light reaching different ecosystems. 
E)  Satellites detect differences by measuring the amount of water vapor emitted by transpiring producers.

Question 17

The amount of chemical energy in consumers' food that is converted to their own new biomass during a given time period is known as which of the following?

Accepted Answer

A)  biomass 
B)  standing crop 
C)  biomagnification 
D)  primary production 
E)  secondary production 
A)  biomass 
B)  standing crop 
C)  biomagnification 
D)  primary production 
E)  secondary production

Question 18

If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, starting from phytoplankton to zooplankton to fish to seals to polar bears, then which of the following could be true?

Accepted Answer

A)  Polar bears can provide more food for humans than seals can. 
B)  The total biomass of the fish is lower than that of the seals. 
C)  Seal meat probably contains the highest concentrations of fat-soluble toxins. 
D)  Seal populations are larger than fish populations. 
E)  The fish can potentially provide more food for humans than the seal meat can. 
A)  Polar bears can provide more food for humans than seals can. 
B)  The total biomass of the fish is lower than that of the seals. 
C)  Seal meat probably contains the highest concentrations of fat-soluble toxins. 
D)  Seal populations are larger than fish populations. 
E)  The fish can potentially provide more food for humans than the seal meat can.

Question 19

A cow's herbivorous diet indicates that it is a(n)

Accepted Answer

A)  primary consumer. 
B)  secondary consumer. 
C)  decomposer. 
D)  autotroph. 
E)  producer. 
A)  primary consumer. 
B)  secondary consumer. 
C)  decomposer. 
D)  autotroph. 
E)  producer.

Question 20

What percentage of solar radiation striking a plant is converted into chemical energy?

Accepted Answer

A)  1% 
B)  10% 
C)  25% 
D)  50% 
E)  100% 
A)  1% 
B)  10% 
C)  25% 
D)  50% 
E)  100%

Exam 55: Ecosystems and Restoration Ecology

What is the primary limiting factor for aquatic productivity?

Which of the following is true of detrivores?

Which of the following statements is true?

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

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

Many homeowners mow their lawns during the summer and collect the clippings, which are then hauled to the local landfill. Which of the following actions would most benefit the suburban ecosystem?

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

Nitrogen is available to plants only in the form of

Which of these ecosystems accounts for the largest amount of Earth's net primary productivity?

The major role of detrivores in ecosystems is to

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?

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 3-hectare lake in the American Midwest suddenly has succumbed to an algal bloom. What is the likely cause of eutrophication in freshwater ecosystems, such as this one?

Which of the following is an example of a local biogeochemical cycle?

Food web for a particular terrestrial ecosystem (arrows represent energy flow and letters represent species) -Examine this food web for a particular terrestrial ecosystem. Which pair of species could be omnivores?

How is it that satellites can detect differences in primary productivity on Earth?

The amount of chemical energy in consumers' food that is converted to their own new biomass during a given time period is known as which of the following?

If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, starting from phytoplankton to zooplankton to fish to seals to polar bears, then which of the following could be true?

A cow's herbivorous diet indicates that it is a(n)

What percentage of solar radiation striking a plant is converted into chemical energy?

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Conservation Biology and Global Change

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