Question 1

Which of the following most accurately describes the fate of incoming solar radiation from the sun?

Accepted Answer

A)  Most of the incoming solar radiation is transmitted through plant leaves or lost as heat. 
B)  A tiny fraction of the incoming solar radiation is absorbed by photosynthetic plant pigments. 
C)  Most incoming solar radiation strikes and is absorbed by Earth's land surfaces. 
D)  Solar radiation is least intense at the tropics. 
A)  Most of the incoming solar radiation is transmitted through plant leaves or lost as heat. 
B)  A tiny fraction of the incoming solar radiation is absorbed by photosynthetic plant pigments. 
C)  Most incoming solar radiation strikes and is absorbed by Earth's land surfaces. 
D)  Solar radiation is least intense at the tropics.

Question 2

Which of the following is a reason that logged tropical rain forest soils typically have nutrient-poor soils?

Accepted Answer

A)  Tropical bedrock contains little phosphorous. 
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)  The cation exchange capacity of the soil is reversed as a result of logging. 
A)  Tropical bedrock contains little phosphorous. 
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)  The cation exchange capacity of the soil is reversed as a result of logging.

Question 3

Use the following figure to answer the question.   Which of the following claims is most consistent with the figure regarding productivity in this ecosystem?

Accepted Answer

A)  Primary consumers consume less biomass than secondary consumers. 
B)  Between 80% and 90% of the energy is lost between most trophic levels. 
C)  Between 10% and 20% of the energy is lost between most trophic levels. 
D)  Productivity increases with each trophic level. 
A)  Primary consumers consume less biomass than secondary consumers. 
B)  Between 80% and 90% of the energy is lost between most trophic levels. 
C)  Between 10% and 20% of the energy is lost between most trophic levels. 
D)  Productivity increases with each trophic level.

Question 4

Which of the following is an example of bioremediation?

Accepted Answer

A)  adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen availability 
B)  using a bulldozer to regrade a strip mine 
C)  reconfiguring the channel of a river 
D)  adding seeds of a chromium-accumulating plant to soil contaminated by chromium 
A)  adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen availability 
B)  using a bulldozer to regrade a strip mine 
C)  reconfiguring the channel of a river 
D)  adding seeds of a chromium-accumulating plant to soil contaminated by chromium

Question 5

Which of the following best describes the role of nitrifying bacteria in the nitrogen cycle?

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 6

Which of the following was a conclusion of the Hubbard Brook watershed deforestation experiment?

Accepted Answer

A)  deforestation decreased water runoff 
B)  nitrate concentration in waters draining from the deforested area were lowest 
C)  calcium levels remained high in the soil of deforested areas 
D)  nitrate concentration in waters draining from the deforested area became dangerously high 
A)  deforestation decreased water runoff 
B)  nitrate concentration in waters draining from the deforested area were lowest 
C)  calcium levels remained high in the soil of deforested areas 
D)  nitrate concentration in waters draining from the deforested area became dangerously high

Question 7

Owls eat rats, mice, shrews, and small birds. Assume that, over a period of time, an owl consumes 5,000 J of animal material. The owl loses 2,300 J in feces and owl pellets and uses 2,500 J for cellular respiration. Which of the following best estimates the production efficiency of this owl?

Accepted Answer

A)  8% 
B)  7.4% 
C)  2% 
D)  40% 
A)  8% 
B)  7.4% 
C)  2% 
D)  40%

Question 8

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

Accepted Answer

A)  Globally, phosphorous availability is most limiting to primary productivity. 
B)  Adding a nonlimiting nutrient will stimulate primary productivity. 
C)  Phosphorous is sometimes unavailable to producers due to leaching. 
D)  Alkaline soils are more productive than acidic soils. 
A)  Globally, phosphorous availability is most limiting to primary productivity. 
B)  Adding a nonlimiting nutrient will stimulate primary productivity. 
C)  Phosphorous is sometimes unavailable to producers due to leaching. 
D)  Alkaline soils are more productive than acidic soils.

Question 9

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 cycling rates tend to be limited by decomposition. 
D)  Energy transfer between trophic levels is usually less than 20 percent efficient. 
A)  Many primary and higher-order consumers are opportunistic feeders. 
B)  Decomposers compete with higher-order consumers for nutrients and energy. 
C)  Nutrient cycling rates tend to be limited by decomposition. 
D)  Energy transfer between trophic levels is usually less than 20 percent efficient.

Question 10

During a year, plants never use 100% of the incoming solar radiation for photosynthesis. Which of the following is the most reasonable explanation for this?

Accepted Answer

A)  Plants cannot photosynthesize as well in warm temperatures as in cold temperatures. 
B)  Plants do not intercept all incoming light, as some light will strike water, bare soil, or rock. 
C)  The pigments that drive photosynthesis absorb all of the wavelengths of light; however, some of the light is subsequently reflected off the plant. 
D)  At least 75% of all incoming light is reflected, absorbed, or scattered back by clouds in the atmosphere. 
A)  Plants cannot photosynthesize as well in warm temperatures as in cold temperatures. 
B)  Plants do not intercept all incoming light, as some light will strike water, bare soil, or rock. 
C)  The pigments that drive photosynthesis absorb all of the wavelengths of light; however, some of the light is subsequently reflected off the plant. 
D)  At least 75% of all incoming light is reflected, absorbed, or scattered back by clouds in the atmosphere.

Question 11

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)  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)  Both decomposition rate and NEP would increase. 
C)  Decomposition rate would increase and NEP would decrease. 
D)  Decomposition rate would decrease and NEP would increase.

Question 12

Which of the following best explains why an ecosystem that exhibits very low net primary production [NPP, measured as J/(m2 x year)] could still represent one of the ecosystems that contributes the most to global net primary production?

Accepted Answer

A)  Ecosystems with very low NPP may cover vast areas of the Earth's surface. 
B)  Ecosystems with very low NPP may have tight recycling of energy. 
C)  Low NPP ecosystems often store a lot of heat. 
D)  Higher NPP ecosystems are often located at latitudes where sunlight is less intense. 
A)  Ecosystems with very low NPP may cover vast areas of the Earth's surface. 
B)  Ecosystems with very low NPP may have tight recycling of energy. 
C)  Low NPP ecosystems often store a lot of heat. 
D)  Higher NPP ecosystems are often located at latitudes where sunlight is less intense.

Question 13

Which of the following are the two key emergent properties of an ecosystem?

Accepted Answer

A)  decomposition and nutrient cycling 
B)  solar radiation and primary production 
C)  photosynthesis and cellular respiration 
D)  energy flow and chemical cycling 
A)  decomposition and nutrient cycling 
B)  solar radiation and primary production 
C)  photosynthesis and cellular respiration 
D)  energy flow and chemical cycling

Question 14

Which of the following claims about marine ecosystem productivity is the most accurate?

Accepted Answer

A)  production near the equator is highest because incoming solar radiation is the most intense 
B)  production near the equator is highest because reefs support a higher level of biodiversity 
C)  production in regions where there is higher micro- and macronutrient availability is highest 
D)  production in the Antarctic Ocean is one of the lowest due to the colder water temperatures 
A)  production near the equator is highest because incoming solar radiation is the most intense 
B)  production near the equator is highest because reefs support a higher level of biodiversity 
C)  production in regions where there is higher micro- and macronutrient availability is highest 
D)  production in the Antarctic Ocean is one of the lowest due to the colder water temperatures

Question 15

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 
C)  biomagnification of toxic materials limits the secondary consumers and top carnivores 
D)  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 
C)  biomagnification of toxic materials limits the secondary consumers and top carnivores 
D)  top carnivores and secondary consumers have a more general diet than primary producers

Question 16

Acid precipitation lowered the pH of soil in a terrestrial ecosystem that supported a diverse community of plants and animals. The decrease in pH eliminated all nitrogen-fixing bacteria populations in the area. Which prediction most accurately reflects the impact this will have on the community?

Accepted Answer

A)  Since phosphorus can replace nitrogen as an essential nutrient, the impact will be minimal. 
B)  Plants can obtain the nitrogen necessary for growth from the atmosphere, but bacterial communities will be negatively impacted. 
C)  Primary producers will suffer from nitrogen deficiency and the entire community will experience a decrease in carrying capacity. 
D)  The decrease in pH actually increases the availability of soil nutrients, so other nutrients that were less available cause an increase in primary production and an increase in biomass at other trophic levels. 
A)  Since phosphorus can replace nitrogen as an essential nutrient, the impact will be minimal. 
B)  Plants can obtain the nitrogen necessary for growth from the atmosphere, but bacterial communities will be negatively impacted. 
C)  Primary producers will suffer from nitrogen deficiency and the entire community will experience a decrease in carrying capacity. 
D)  The decrease in pH actually increases the availability of soil nutrients, so other nutrients that were less available cause an increase in primary production and an increase in biomass at other trophic levels.

Question 17

A porcupine eats 3,000 J of plant material. Of this, 2,100 J is indigestible and is eliminated as feces, 800 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)  11% 
D)  33% 
A)  0.03% 
B)  3% 
C)  11% 
D)  33%

Question 18

Use the following figure to answer the question.   Food web for a particular terrestrial ecosystem (arrows represent energy flow and numbers represent species)
Which species in the food web most likely represents both a primary and secondary consumer?

Accepted Answer

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

Question 19

Assuming it were technologically feasible, a scientist could hypothetically track the long-term fate (for example, 100 years) of every atom in a single molecule of carbon dioxide that initially moves from the air into a plant. This fact is a manifestation of which of the following physical laws?

Accepted Answer

A)  conservation of energy 
B)  conservation of mass 
C)  conservation of nutrients 
D)  energy and chemical flow 
A)  conservation of energy 
B)  conservation of mass 
C)  conservation of nutrients 
D)  energy and chemical flow

Question 20

Which of the following statements is correct about biogeochemical cycling?

Accepted Answer

A)  Phosphorus is the limiting nutrient that most widely affects biomass production. 
B)  The phosphorus cycle involves the weathering of rocks. 
C)  The carbon cycle has maintained a constant atmospheric concentration of carbon dioxide for the past million years. 
D)  The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic components of the ecosystem. 
A)  Phosphorus is the limiting nutrient that most widely affects biomass production. 
B)  The phosphorus cycle involves the weathering of rocks. 
C)  The carbon cycle has maintained a constant atmospheric concentration of carbon dioxide for the past million years. 
D)  The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic components of the ecosystem.

Exam 55: Energy Flow and Chemical Cycling in Ecosystems

Which of the following most accurately describes the fate of incoming solar radiation from the sun?

Which of the following is a reason that logged tropical rain forest soils typically have nutrient-poor soils?

Use the following figure to answer the question. Which of the following claims is most consistent with the figure regarding productivity in this ecosystem?

Which of the following is an example of bioremediation?

Which of the following best describes the role of nitrifying bacteria in the nitrogen cycle?

Which of the following was a conclusion of the Hubbard Brook watershed deforestation experiment?

Owls eat rats, mice, shrews, and small birds. Assume that, over a period of time, an owl consumes 5,000 J of animal material. The owl loses 2,300 J in feces and owl pellets and uses 2,500 J for cellular respiration. Which of the following best estimates the production efficiency of this owl?

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

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

During a year, plants never use 100% of the incoming solar radiation for photosynthesis. Which of the following is the most reasonable explanation for this?

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

Which of the following best explains why an ecosystem that exhibits very low net primary production [NPP, measured as J/(m2 x year)] could still represent one of the ecosystems that contributes the most to global net primary production?

Which of the following are the two key emergent properties of an ecosystem?

Which of the following claims about marine ecosystem productivity is the most accurate?

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 ________.

Acid precipitation lowered the pH of soil in a terrestrial ecosystem that supported a diverse community of plants and animals. The decrease in pH eliminated all nitrogen-fixing bacteria populations in the area. Which prediction most accurately reflects the impact this will have on the community?

A porcupine eats 3,000 J of plant material. Of this, 2,100 J is indigestible and is eliminated as feces, 800 J are used in cellular respiration, and 100 J are used for growth and reproduction. What is the approximate production efficiency of this animal?

Use the following figure to answer the question. Food web for a particular terrestrial ecosystem (arrows represent energy flow and numbers represent species) Which species in the food web most likely represents both a primary and secondary consumer?

Assuming it were technologically feasible, a scientist could hypothetically track the long-term fate (for example, 100 years) of every atom in a single molecule of carbon dioxide that initially moves from the air into a plant. This fact is a manifestation of which of the following physical laws?

Which of the following statements is correct about biogeochemical cycling?

Biology and Its Themes

Atoms and Molecules

The Chemistry of Water

Carbon: the Basis of Molecular Diversity

Biological Macromolecules and Lipids

Energy and Life

Cell Structure and Function

Cell Membranes

Cellular Signaling

Cell Respiration

Photosynthetic Processes

Mitosis

Sexual Life Cycles and Meiosis

Mendelian Genetics

Linkage and Chromosomes

Nucleic Acids and Inheritance

Expression of Genes

Control of Gene Expression

Dna Technology

The Evolution of Genomes

How Evolution Works

Phylogenetic Reconstruction

Microevolution

Species and Speciation

Macroevolution

Introduction to Viruses

Prokaryotes

The Origin and Evolution of Eukaryotes

Nonvascular and Seedless Vascular Plants

Seed Plants

Introduction to Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure and Growth

Transport in Vascular Plants

Plant Nutrition

Reproduction of Flowering Plants

Plant Signals and Behavior

The Animal Body

Chemical Signals in Animals

Animal Digestive Systems

Animal Transport Systems

Animal Excretory Systems

Animal Reproductive Systems

Development in Animals

Animal Defenses Against Infection

Electrical Signals in Animals

Neural Regulation in Animals

Sensation and Movement in Animals

An Overview of Ecology

Behavioral Ecology

Populations and Life History Traits

Biodiversity and Communities

Conservation and Global Ecology

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