Question 1

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

Accepted Answer

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

Question 2

Please use the following information to answer the question(s) below.
Starting with the European settlers, humans have introduced earthworms from Europe and Asia into North American forests. These introductions continue through the transport of soil that contains non-native earthworms, such as during construction, and through the release of non-native earthworms used for fishing. The effects of non-native earthworms are especially large in forests that did not have any native earthworms. For example, forests of the Great Lakes region did not previously have earthworms until humans introduced them. When non-native earthworms are introduced, the thick layer of leaf litter disappears quickly, thereby altering biogeochemical cycles.
-You conduct an experiment to compare the nitrogen cycle in soils with and without non-native earthworms. Predict the results of your experiment.

Accepted Answer

A)  The soils with earthworms will have a faster rate of nitrogen fixation. 
B)  The soils with earthworms will have a faster rate of ammonification. 
C)  The soils with earthworms will have a slower rate of denitrification. 
D)  The soils with earthworms will have a slower rate of nitrification. 
A)  The soils with earthworms will have a faster rate of nitrogen fixation. 
B)  The soils with earthworms will have a faster rate of ammonification. 
C)  The soils with earthworms will have a slower rate of denitrification. 
D)  The soils with earthworms will have a slower rate of nitrification.

Question 3

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 4

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

Accepted Answer

A)  Fewer 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 than do omnivores. 
E)  Eating meat is an inefficient way of acquiring photosynthetic productivity. 
A)  Fewer 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 than do omnivores. 
E)  Eating meat is an inefficient way of acquiring photosynthetic productivity.

Question 5

How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level predators?

Accepted Answer

A)  Top-level predators are restricted to small populations that are sparsely distributed. 
B)  Predators have relatively large population sizes. 
C)  Predators are more disease-prone than animals at lower trophic levels. 
D)  Predators have short life spans and short reproductive periods. 
E)  Top-level predators are more likely to be stricken with parasites. 
A)  Top-level predators are restricted to small populations that are sparsely distributed. 
B)  Predators have relatively large population sizes. 
C)  Predators are more disease-prone than animals at lower trophic levels. 
D)  Predators have short life spans and short reproductive periods. 
E)  Top-level predators are more likely to be stricken with parasites.

Question 6

Figure 42.3
-In the diagram of the nitrogen cycle in Figure 42.3, which number represents the ammonium ion (NH4+)?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
A)  1 
B)  2 
C)  3 
D)  4

Question 7

Please use the following information to answer the question(s) below.
The tundra biome is rapidly changing as a result of global warming. Studying the energy budget of the tundra can help scientists to evaluate the magnitude of these changes. In a randomly selected square meter of tundra, the amount of plant biomass is 200 g. The amount of new plant biomass added in a year is 100 g. In the same square meter, the total biomass added in a year is 15 g. A grasshopper that eats 1 g of plant biomass is able to use 0.15 g of that biomass for growth. The grasshopper cannot assimilate 50% of the plant's biomass.
-What is the net ecosystem production of this square meter of tundra?

Accepted Answer

A)  100 g 
B)  85 g 
C)  15 g 
D)  1 g 
E)  0.15 g 
A)  100 g 
B)  85 g 
C)  15 g 
D)  1 g 
E)  0.15 g

Question 8

Figure 42.1 Food web for a particular terrestrial ecosystem (arrows represent energy flow and numbers represent species)
-Examine the food web for a particular terrestrial ecosystem in Figure 42.1. Which species is autotrophic?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 9

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. 
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.

Question 10

Please use the following information to answer the question(s) 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)  In the ambient condition, plants are limited by nitrogen even when mycorrhizae are present. 
B)  Interactions with mycorrhizae allow for the highest primary production levels regardless of nitrogen level. 
C)  Interactions with mycorrhizae are always mutualistic. 
D)  Mycorrhizae should be added to restore successfully grasslands with high soil nitrogen. 
A)  In the ambient condition, plants are limited by nitrogen even when mycorrhizae are present. 
B)  Interactions with mycorrhizae allow for the highest primary production levels regardless of nitrogen level. 
C)  Interactions with mycorrhizae are always mutualistic. 
D)  Mycorrhizae should be added to restore successfully grasslands with high soil nitrogen.

Question 11

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. 
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. 
A)  NPP can be expressed in energy per unit of area per 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.

Question 12

The major role of detritivores 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 13

Which of these ecosystems has the lowest net primary production per square meter?

Accepted Answer

A)  a salt marsh 
B)  an open ocean 
C)  a coral reef 
D)  a tropical rain forest 
A)  a salt marsh 
B)  an open ocean 
C)  a coral reef 
D)  a tropical rain forest

Question 14

Which of the following is an example of an ecosystem?

Accepted Answer

A)  all of the brook trout in a 500-square-hectare river drainage system 
B)  the plants, animals, and decomposers that inhabit an alpine meadow 
C)  a pond and all of the plant and animal species that live in it 
D)  the intricate interactions of the various plant and animal species on a savanna during a drought 
E)  all of the organisms and their physical environment in a tropical rain forest 
A)  all of the brook trout in a 500-square-hectare river drainage system 
B)  the plants, animals, and decomposers that inhabit an alpine meadow 
C)  a pond and all of the plant and animal species that live in it 
D)  the intricate interactions of the various plant and animal species on a savanna during a drought 
E)  all of the organisms and their physical environment in a tropical rain forest

Question 15

Approximately 1% of the solar radiation that strikes a plant is converted into the chemical bond energy of sugars. Why is this amount so low?

Accepted Answer

A)  Approximately 99% of the solar radiation is converted to heat energy. 
B)  Only 1% of the wavelengths of visible light is absorbed by photosynthetic pigments. 
C)  Most solar energy strikes water and land surfaces. 
D)  Approximately 99% of the solar radiation is reflected. 
E)  Only the green wavelengths are absorbed by plants for photosynthesis. 
A)  Approximately 99% of the solar radiation is converted to heat energy. 
B)  Only 1% of the wavelengths of visible light is absorbed by photosynthetic pigments. 
C)  Most solar energy strikes water and land surfaces. 
D)  Approximately 99% of the solar radiation is reflected. 
E)  Only the green wavelengths are absorbed by plants for photosynthesis.

Question 16

The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as

Accepted Answer

A)  restoration ecology. 
B)  thermodynamics. 
C)  eutrophication. 
D)  biogeochemistry. 
A)  restoration ecology. 
B)  thermodynamics. 
C)  eutrophication. 
D)  biogeochemistry.

Question 17

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. 
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 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 ecosystems 
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

Question 19

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 Southern Ocean (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. 
A)  follow whale migrations in order to determine where most nutrients are located. 
B)  observe Southern Ocean (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.

Question 20

Which of the following terms encompasses all of the others?

Accepted Answer

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

Exam 42: Ecosystems and Energy

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

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

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

How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level predators?

Figure 42.3 -In the diagram of the nitrogen cycle in Figure 42.3, which number represents the ammonium ion (NH4+)?

Figure 42.1 Food web for a particular terrestrial ecosystem (arrows represent energy flow and numbers represent species) -Examine the food web for a particular terrestrial ecosystem in Figure 42.1. Which species is autotrophic?

Trophic efficiency is

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

The major role of detritivores in ecosystems is to

Which of these ecosystems has the lowest net primary production per square meter?

Which of the following is an example of an ecosystem?

Approximately 1% of the solar radiation that strikes a plant is converted into the chemical bond energy of sugars. Why is this amount so low?

The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as

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

What is the goal of restoration ecology?

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

Which of the following terms encompasses all of the others?

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development, Stem Cells, and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition, Nutrition, and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons, Synapses, and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Species Interactions

Global Ecology and Conservation Biology

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