Question 1

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 tropic levels is in almost all cases less than 20% efficient. 
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 tropic levels is in almost all cases less than 20% efficient. E

Question 2

Use the information below to answer the following questions.
Flycatcher birds that migrate from Africa to Europe feed their nestlings mostly with moth caterpillars. The data presented show the mean dates of egg laying, hatching, and fledging of flycatcher young, and the 1980 and 2000 peak mass of caterpillars.
   
Figure 55.4
-Why are ecologists concerned about the shift in date from May 28 in 1980 to May 15 in 2000 of the caterpillar peak mass?

Accepted Answer

A) The caterpillars will eat much of the foliage of the trees where flycatchers nest, and their nests will be more open to predation. 
B) The earlier hatching of caterpillars will compete with other insect larval forms on which the flycatchers also feed their young. 
C) The flycatcher nestlings in 2000 will miss the peak mass of caterpillars and may not be as well fed. 
D) The flycatchers will have to migrate sooner to match their brood-rearing season with the time of caterpillar peak mass. 
E) Pesticides, which have a negative effect on the ecosystem, will have to be used to control the earlier outbreak of caterpillar hatching. 
A) The caterpillars will eat much of the foliage of the trees where flycatchers nest, and their nests will be more open to predation. 
B) The earlier hatching of caterpillars will compete with other insect larval forms on which the flycatchers also feed their young. 
C) The flycatcher nestlings in 2000 will miss the peak mass of caterpillars and may not be as well fed. 
D) The flycatchers will have to migrate sooner to match their brood-rearing season with the time of caterpillar peak mass. 
E) Pesticides, which have a negative effect on the ecosystem, will have to be used to control the earlier outbreak of caterpillar hatching. C

Question 3

For most terrestrial ecosystems, pyramids of numbers, biomass, and energy are essentially the same-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 as a result of keeping the organisms alive. 
C) as matter passes through ecosystems, some of it is lost to the environment. 
D) biomagnification of toxic materials 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 as a result of keeping the organisms alive. 
C) as matter passes through ecosystems, some of it is lost to the environment. 
D) biomagnification of toxic materials limits the secondary consumers and top carnivores. 
E) top carnivores and secondary consumers have a more general diet than primary producers. B

Question 4

Which of the following ecosystems would likely have a larger net primary productivity/hectare?

Accepted Answer

A) open ocean because of the total biomass of photosynthetic autotrophs 
B) grassland because of the small standing crop biomass that results from consumption by herbivores and rapid decomposition 
C) tropical rainforest because of the massive standing crop biomass and species diversity. 
D) cave due to the lack of photosynthetic autotrophs 
E) tundra because of the incredibly rapid period of growth during the summer season. 
A) open ocean because of the total biomass of photosynthetic autotrophs 
B) grassland because of the small standing crop biomass that results from consumption by herbivores and rapid decomposition 
C) tropical rainforest because of the massive standing crop biomass and species diversity. 
D) cave due to the lack of photosynthetic autotrophs 
E) tundra because of the incredibly rapid period of growth during the summer season.

Question 5

Which of the following statements best describes why biologists are currently concerned with global warming and the thawing of permafrost in many areas of the tundra biome?

Accepted Answer

A) The thawing process will likely decrease the abundance and diversity of soil-dwelling organisms in tundra habitats. 
B) The bacterial decomposition of the thawed organic materials on the widespread areas of the tundra will produce large quantities of CO2, which will add to greenhouse gases and exacerbate global warming. 
C) Oil and coal deposits will thaw and rise to the surface (because of their lower density)of the tundra, destroying millions of acres of arctic habitat. 
D) Populations of humans inhabiting the arctic will have to move to more southern latitudes, resulting in increased competition for resources in already densely populated areas. 
E) Migratory species of waterfowl will likely be less successful finding food in thawed tundra, and population numbers will drop dramatically. 
A) The thawing process will likely decrease the abundance and diversity of soil-dwelling organisms in tundra habitats. 
B) The bacterial decomposition of the thawed organic materials on the widespread areas of the tundra will produce large quantities of CO2, which will add to greenhouse gases and exacerbate global warming. 
C) Oil and coal deposits will thaw and rise to the surface (because of their lower density)of the tundra, destroying millions of acres of arctic habitat. 
D) Populations of humans inhabiting the arctic will have to move to more southern latitudes, resulting in increased competition for resources in already densely populated areas. 
E) Migratory species of waterfowl will likely be less successful finding food in thawed tundra, and population numbers will drop dramatically.

Question 6

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 7

Of the following pairs, which are the main decomposers in a terrestrial ecosystem?

Accepted Answer

A) fungi and prokaryotes 
B) plants and mosses 
C) insects and mollusks 
D) mammals and birds 
E) annelids and nematodes 
A) fungi and prokaryotes 
B) plants and mosses 
C) insects and mollusks 
D) mammals and birds 
E) annelids and nematodes

Question 8

Refer to Figure 55.1, a diagram of a food web, for the following questions. (Arrows represent energy flow and letters represent species.)
   
Figure 55.1
-If this were a marine food web, the smallest organism might be

Accepted Answer

A) A. 
B) F. 
C) C. 
D) I. 
E) E. 
A) A. 
B) F. 
C) C. 
D) I. 
E) E.

Question 9

Which of the following has the smallest biomass?

Accepted Answer

A) hawk 
B) snake 
C) shrew 
D) grasshopper 
E) grass 
A) hawk 
B) snake 
C) shrew 
D) grasshopper 
E) grass

Question 10

Which of the following statements is correct about biogeochemical cycling?

Accepted Answer

A) The phosphorus cycle involves the recycling of atmospheric phosphorus. 
B) The phosphorus cycle is a cycle that involves the weathering of rocks. 
C) The carbon cycle is a localized cycle that primarily involves the burning of fossil fuels. 
D) The carbon cycle has maintained a constant atmospheric concentration of CO2 for the past million years. 
E) The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic components of the ecosystem. 
A) The phosphorus cycle involves the recycling of atmospheric phosphorus. 
B) The phosphorus cycle is a cycle that involves the weathering of rocks. 
C) The carbon cycle is a localized cycle that primarily involves the burning of fossil fuels. 
D) The carbon cycle has maintained a constant atmospheric concentration of CO2 for the past million years. 
E) The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic components of the ecosystem.

Question 11

Which of the following is an example of an ecosystem?

Accepted Answer

A) All of the brook trout in a 500 hectare2 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) Interactions between all of the organisms and their physical environment in a tropical rain forest. 
A) All of the brook trout in a 500 hectare2 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) Interactions between all of the organisms and their physical environment in a tropical rain forest.

Question 12

Which of the following is a consequence of biological magnification?

Accepted Answer

A) Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers. 
B) Populations of top-level predators are generally smaller than populations of primary consumers. 
C) The biomass of producers in an ecosystem is generally higher than the biomass of primary consumers. 
D) Only a small portion of the energy captured by producers is transferred to consumers. 
E) The amount of biomass in the producer level of an ecosystem decreases if the producer turnover time increases. 
A) Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers. 
B) Populations of top-level predators are generally smaller than populations of primary consumers. 
C) The biomass of producers in an ecosystem is generally higher than the biomass of primary consumers. 
D) Only a small portion of the energy captured by producers is transferred to consumers. 
E) The amount of biomass in the producer level of an ecosystem decreases if the producer turnover time increases.

Question 13

Human-induced modifications of the nitrogen cycle can result in

Accepted Answer

A) eutrophication of adjacent wetlands. 
B) decreased availability of fixed nitrogen to primary producers. 
C) accumulation of toxic levels of N2 in groundwater. 
D) extermination of nitrogen-fixing bacteria on agricultural lands. 
E) deprivation of nitrogen to ecosystems adjacent to nitrogen application. 
A) eutrophication of adjacent wetlands. 
B) decreased availability of fixed nitrogen to primary producers. 
C) accumulation of toxic levels of N2 in groundwater. 
D) extermination of nitrogen-fixing bacteria on agricultural lands. 
E) deprivation of nitrogen to ecosystems adjacent to nitrogen application.

Question 14

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 15

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 16

If you wanted to convert excess grain into the greatest amount of animal biomass, to which animal would you feed the grain?

Accepted Answer

A) chickens 
B) mice 
C) cattle 
D) carp (a type of fish) 
E) mealworms (larval insects) 
A) chickens 
B) mice 
C) cattle 
D) carp (a type of fish) 
E) mealworms (larval insects)

Question 17

How is it that the open ocean produces the highest net primary productivity of Earth's ecosystems, yet net primary productivity per square meter is relatively low?

Accepted Answer

A) Oceans contain greater concentrations of nutrients compared to other ecosystems. 
B) Oceans receive a greater amount of solar energy per unit area. 
C) Oceans have the greatest total area. 
D) Oceans possess greater species diversity. 
E) Oceanic producers are generally much smaller than its consumers. 
A) Oceans contain greater concentrations of nutrients compared to other ecosystems. 
B) Oceans receive a greater amount of solar energy per unit area. 
C) Oceans have the greatest total area. 
D) Oceans possess greater species diversity. 
E) Oceanic producers are generally much smaller than its consumers.

Question 18

Use the incomplete diagram below, illustrating some of the steps involved in eutrophication to answer the following questions.
   Figure 55.3
-What would be a likely entry for box B?

Accepted Answer

A) decomposer population carries on cellular respiration and uses up oxygen 
B) plants no longer producing oxygen 
C) warm water holding less oxygen than cold water 
D) fish that cannot acclimate to low oxygen levels 
E) carbon dioxide building up from cellular respiration by decomposers 
A) decomposer population carries on cellular respiration and uses up oxygen 
B) plants no longer producing oxygen 
C) warm water holding less oxygen than cold water 
D) fish that cannot acclimate to low oxygen levels 
E) carbon dioxide building up from cellular respiration by decomposers

Question 19

Ecosystems are

Accepted Answer

A) processors of energy and transformers of matter. 
B) processors of matter and transformers of energy. 
C) processors of matter and energy. 
D) transformers of matter but not of energy. 
E) neither transformers or processors of matter nor energy. 
A) processors of energy and transformers of matter. 
B) processors of matter and transformers of energy. 
C) processors of matter and energy. 
D) transformers of matter but not of energy. 
E) neither transformers or processors of matter nor energy.

Question 20

Some global warming models predict that, if permafrost in the tundra regions in the northern hemisphere melts, atmospheric CO2 levels will increase. Which of the following statements best explains this prediction?

Accepted Answer

A) The heat released by the melting of the ice on such a vast scale will cause atmospheric CO2 saturation levels to increase. 
B) All of the tundra producers will die if the permafrost melts, and because the tundra regions are vast in the northern hemisphere the tundra plants will not take part in photosynthetic removal of atmospheric CO2. 
C) CO2 tied up in the permafrost ice will be released during a thaw. 
D) All of the undecayed organic material would be subject to decomposition following a thaw, which would lead to incredible increase in global cellular respiration, and add to atmospheric CO2. 
E) All of the permafrost ice would become runoff, and this volume of water will cause sea levels to rise globally, flooding some of the most important photosynthetic CO2 sink regions on the planet. 
A) The heat released by the melting of the ice on such a vast scale will cause atmospheric CO2 saturation levels to increase. 
B) All of the tundra producers will die if the permafrost melts, and because the tundra regions are vast in the northern hemisphere the tundra plants will not take part in photosynthetic removal of atmospheric CO2. 
C) CO2 tied up in the permafrost ice will be released during a thaw. 
D) All of the undecayed organic material would be subject to decomposition following a thaw, which would lead to incredible increase in global cellular respiration, and add to atmospheric CO2. 
E) All of the permafrost ice would become runoff, and this volume of water will cause sea levels to rise globally, flooding some of the most important photosynthetic CO2 sink regions on the planet.

Exam 55: Ecosystems

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

For most terrestrial ecosystems, pyramids of numbers, biomass, and energy are essentially the same-they have a broad base and a narrow top. The primary reason for this pattern is that

Which of the following ecosystems would likely have a larger net primary productivity/hectare?

Which of the following statements best describes why biologists are currently concerned with global warming and the thawing of permafrost in many areas of the tundra biome?

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

Of the following pairs, which are the main decomposers in a terrestrial ecosystem?

Refer to Figure 55.1, a diagram of a food web, for the following questions. (Arrows represent energy flow and letters represent species.) Figure 55.1 -If this were a marine food web, the smallest organism might be

Which of the following has the smallest biomass?

Which of the following statements is correct about biogeochemical cycling?

Which of the following is an example of an ecosystem?

Which of the following is a consequence of biological magnification?

Human-induced modifications of the nitrogen cycle can result in

Which of the following statements is True?

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

If you wanted to convert excess grain into the greatest amount of animal biomass, to which animal would you feed the grain?

How is it that the open ocean produces the highest net primary productivity of Earth's ecosystems, yet net primary productivity per square meter is relatively low?

Use the incomplete diagram below, illustrating some of the steps involved in eutrophication to answer the following questions. Figure 55.3 -What would be a likely entry for box B?

Ecosystems are

Some global warming models predict that, if permafrost in the tundra regions in the northern hemisphere melts, atmospheric CO2 levels will increase. Which of the following statements best explains this prediction?

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

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: Harvesting Chemical Energy

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

Control 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 Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

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 Restoration Ecology

Filters