Question 1

Which of the following locations is the main reservoir for nitrogen in Earth's nitrogen cycle?

Accepted Answer

A)  atmosphere 
B)  sedimentary bedrock 
C)  fossilized plant and animal remains (coal, oil, and natural gas) 
D)  plant and animal biomass 
E)  soil 
A)  atmosphere 
B)  sedimentary bedrock 
C)  fossilized plant and animal remains (coal, oil, and natural gas) 
D)  plant and animal biomass 
E)  soil A

Question 2

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. 
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. E

Question 3

Why do logged tropical rain forests typically have nutrient-poor soils?

Accepted Answer

A)  Tropical bedrock contains little phosphorus. 
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)  Nutrients evaporate easily into the atmosphere in the post-logged forest. 
A)  Tropical bedrock contains little phosphorus. 
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)  Nutrients evaporate easily into the atmosphere in the post-logged forest. C

Question 4

Nitrifying bacteria participate in the nitrogen cycle mainly by

Accepted Answer

A)  converting nitrogen gas to ammonia. 
B)  releasing ammonium from organic compounds, thus returning it to the soil. 
C)  converting ammonium to nitrate, which plants absorb. 
D)  incorporating nitrogen into amino acids and organic compounds. 
A)  converting nitrogen gas to ammonia. 
B)  releasing ammonium from organic compounds, thus returning it to the soil. 
C)  converting ammonium to nitrate, which plants absorb. 
D)  incorporating nitrogen into amino acids and organic compounds.

Question 5

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 migrating Canada geese lands and spends the night. How could you account for the effect of this event on the pond's nitrogen cycling?

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 the net value of nitrogen associated with the goose visitation into the nitrogen budget of the ecosystem. 
D)  Do nothing. The Canada geese visitation to the lake would have a 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. 
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 the net value of nitrogen associated with the goose visitation into the nitrogen budget of the ecosystem. 
D)  Do nothing. The Canada geese visitation to the lake would have a 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.

Question 6

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.
-The 100 g of new plant biomass is the

Accepted Answer

A)  net ecosystem production. 
B)  gross primary production. 
C)  standing crop. 
D)  secondary production. 
E)  net primary production. 
A)  net ecosystem production. 
B)  gross primary production. 
C)  standing crop. 
D)  secondary production. 
E)  net primary production.

Question 7

Which of the following is a true statement regarding mineral nutrients in soils and their implication for primary productivity?

Accepted Answer

A)  Globally, only phosphorus availability is most limiting to primary productivity. 
B)  Adding a non-limiting nutrient will stimulate primary productivity. 
C)  Adding more of a limiting nutrient will increase primary productivity regardless of other nutrient availability. 
D)  Phosphorus is sometimes unavailable to producers due to leaching. 
E)  Alkaline soils are more productive than acidic soils. 
A)  Globally, only phosphorus availability is most limiting to primary productivity. 
B)  Adding a non-limiting nutrient will stimulate primary productivity. 
C)  Adding more of a limiting nutrient will increase primary productivity regardless of other nutrient availability. 
D)  Phosphorus is sometimes unavailable to producers due to leaching. 
E)  Alkaline soils are more productive than acidic soils.

Question 8

How does phosphorus normally enter ecosystems?

Accepted Answer

A)  as a product from cellular respiration 
B)  as a product from photosynthesis 
C)  from rock weathering 
D)  as atmospheric phosphorus gas 
A)  as a product from cellular respiration 
B)  as a product from photosynthesis 
C)  from rock weathering 
D)  as atmospheric phosphorus gas

Question 9

Aquatic ecosystems are most likely to be limited by which of the following nutrients?

Accepted Answer

A)  nitrogen 
B)  carbon 
C)  potassium 
D)  iron 
E)  zinc 
A)  nitrogen 
B)  carbon 
C)  potassium 
D)  iron 
E)  zinc

Question 10

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%

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

The law of conservation of mass states that matter cannot be created, yet matter is sometimes gained or lost to an ecosystem. What is the reason for this seeming contradiction?

Accepted Answer

A)  Chemoautotrophic organisms can convert matter to energy. 
B)  Ecosystems are open systems; therefore, matter can be moved in/out of an ecosystem from/to another ecosystem. 
C)  Photosynthetic organisms convert sugars to more complex organic molecules. 
D)  Detritivores convert matter to energy. 
E)  Heterotrophs convert heat to energy. 
A)  Chemoautotrophic organisms can convert matter to energy. 
B)  Ecosystems are open systems; therefore, matter can be moved in/out of an ecosystem from/to another ecosystem. 
C)  Photosynthetic organisms convert sugars to more complex organic molecules. 
D)  Detritivores convert matter to energy. 
E)  Heterotrophs convert heat to energy.

Question 13

In Japan, seaweed and seagrass bed reconstruction includes constructing suitable seafloor habitat, transplanting seaweeds and seagrasses from natural beds using artificial substrates, and hand seeding. Which of the following correctly classifies the techniques by the major restoration strategies?

Accepted Answer

A)  biological augmentation-transplanting seaweeds and seagrasses, hand seeding 
B)  biological augmentation-hand seeding and constructing seafloor habitat 
C)  bioremediation-constructing seafloor habitat and using artificial substrates 
D)  bioremediation-transplanting seaweeds and seagrasses, hand seeding 
A)  biological augmentation-transplanting seaweeds and seagrasses, hand seeding 
B)  biological augmentation-hand seeding and constructing seafloor habitat 
C)  bioremediation-constructing seafloor habitat and using artificial substrates 
D)  bioremediation-transplanting seaweeds and seagrasses, hand seeding

Question 14

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

Question 15

Which of the following lists of organisms is ranked in correct order from lowest to highest production efficiency?

Accepted Answer

A)  mammals, fish, insects 
B)  insects, fish, mammals 
C)  fish, insects, mammals 
D)  insects, mammals, fish 
E)  mammals, insects, fish 
A)  mammals, fish, insects 
B)  insects, fish, mammals 
C)  fish, insects, mammals 
D)  insects, mammals, fish 
E)  mammals, insects, fish

Question 16

Rain falls on an agricultural field after a farmer has harvested the corn. Which biogeochemical cycles are involved when runoff from the field flows into a nearby stream?

Accepted Answer

A)  only carbon and water 
B)  only water and nitrogen 
C)  only carbon, nitrogen, and phosphorus 
D)  only water, nitrogen, and phosphorus 
A)  only carbon and water 
B)  only water and nitrogen 
C)  only carbon, nitrogen, and phosphorus 
D)  only water, nitrogen, and phosphorus

Question 17

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. 
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 18

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

Question 19

Which statement most accurately describes how matter and energy are used in ecosystems?

Accepted Answer

A)  Matter flows through ecosystems; energy cycles within ecosystems. 
B)  Energy flows through ecosystems; matter cycles within and through ecosystems. 
C)  Energy can be converted into matter; matter cannot be converted into energy. 
D)  Matter can be converted into energy; energy cannot be converted into matter. 
E)  Matter is used in ecosystems; energy is not. 
A)  Matter flows through ecosystems; energy cycles within ecosystems. 
B)  Energy flows through ecosystems; matter cycles within and through ecosystems. 
C)  Energy can be converted into matter; matter cannot be converted into energy. 
D)  Matter can be converted into energy; energy cannot be converted into matter. 
E)  Matter is used in ecosystems; energy is not.

Question 20

For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and energy are similar in that they have a broad base and a narrow top. The primary reason for this pattern is that

Accepted Answer

A)  secondary consumers and top carnivores require less energy than producers. 
B)  at each step, energy is lost from the system because of the second law of thermodynamics. 
C)  as matter passes through ecosystems, some of it is lost to the environment. 
D)  the accumulation of toxic materials in tissues of animals limits the secondary consumers and top carnivores. 
E)  top carnivores and secondary consumers have a more general diet than primary producers. 
A)  secondary consumers and top carnivores require less energy than producers. 
B)  at each step, energy is lost from the system because of the second law of thermodynamics. 
C)  as matter passes through ecosystems, some of it is lost to the environment. 
D)  the accumulation of toxic materials in tissues of animals limits the secondary consumers and top carnivores. 
E)  top carnivores and secondary consumers have a more general diet than primary producers.

Exam 42: Ecosystems and Energy

Which of the following locations is the main reservoir for nitrogen in Earth's nitrogen cycle?

Nitrogen is available to plants mostly in the form of

Why do logged tropical rain forests typically have nutrient-poor soils?

Nitrifying bacteria participate in the nitrogen cycle mainly by

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 migrating Canada geese lands and spends the night. How could you account for the effect of this event on the pond's nitrogen cycling?

Which of the following is a true statement regarding mineral nutrients in soils and their implication for primary productivity?

How does phosphorus normally enter ecosystems?

Aquatic ecosystems are most likely to be limited by which of the following nutrients?

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

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?

The law of conservation of mass states that matter cannot be created, yet matter is sometimes gained or lost to an ecosystem. What is the reason for this seeming contradiction?

In Japan, seaweed and seagrass bed reconstruction includes constructing suitable seafloor habitat, transplanting seaweeds and seagrasses from natural beds using artificial substrates, and hand seeding. Which of the following correctly classifies the techniques by the major restoration strategies?

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

Which of the following lists of organisms is ranked in correct order from lowest to highest production efficiency?

Rain falls on an agricultural field after a farmer has harvested the corn. Which biogeochemical cycles are involved when runoff from the field flows into a nearby stream?

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

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

Which statement most accurately describes how matter and energy are used in ecosystems?

For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and energy are similar in that they have a broad base and a narrow top. The primary reason for this pattern is that

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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