Question 1

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 more nutrients as compared to other ecosystems. 
B) Oceans receive a lesser amount of solar radiation per unit area. 
C) Oceans have the largest area of all the many ecosystems on Earth. 
D) Ocean ecosystems are less diverse with more autotrophs per unit area. 
E) Oceanic producers are generally much smaller than oceanic consumers. 
A) Oceans contain more nutrients as compared to other ecosystems. 
B) Oceans receive a lesser amount of solar radiation per unit area. 
C) Oceans have the largest area of all the many ecosystems on Earth. 
D) Ocean ecosystems are less diverse with more autotrophs per unit area. 
E) Oceanic producers are generally much smaller than oceanic consumers. C

Question 2

Corn production can be limited by nitrogen levels in the soil.Some farmers reduce the need to apply ammonia to their fields by rotating corn crops with nitrogen-fixing soybean crops.Using soybeans to add nitrogen to degraded soils is an example of

Accepted Answer

A) biological augmentation. 
B) reducing fertilizer runoff. 
C) production efficiency. 
D) plant bioremediation. 
E) trophic level efficiency. 
A) biological augmentation. 
B) reducing fertilizer runoff. 
C) production efficiency. 
D) plant bioremediation. 
E) trophic level efficiency. A

Question 3

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

Accepted Answer

A) atmosphere 
B) solid rock 
C) plant fossils 
D) plant biomass 
E) soil bacteria 
A) atmosphere 
B) solid rock 
C) plant fossils 
D) plant biomass 
E) soil bacteria A

Question 4

Gross primary production in aquatic ecosystems is most likely to be limited by decreases in which of the following nutrient pairs?

Accepted Answer

A) nitrogen and phosphorous 
B) carbon and phosphorous 
C) potassium and phosphorous 
D) iron and phosphorous 
E) molybdenum and phosphorous 
A) nitrogen and phosphorous 
B) carbon and phosphorous 
C) potassium and phosphorous 
D) iron and phosphorous 
E) molybdenum and phosphorous

Question 5

Please use the following information to answer the questions 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 is the dependent variable in the experiment shown in Figure 42.4?

Accepted Answer

A) net primary productivity 
B) total biomass of heterotrophs 
C) net secondary productivity 
D) total biomass of autotrophs 
A) net primary productivity 
B) total biomass of heterotrophs 
C) net secondary productivity 
D) total biomass of autotrophs

Question 6

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 7

Please use the following information to answer the questions 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
-Figure 42.4 shows the results of the experiment.What is (are)the independent variable(s)?

Accepted Answer

A) nitrogen treatment only 
B) biomass of aboveground plant only 
C) presence and absence of mycorrhizae 
D) nitrogen treatment and whether mycorrhizae are present 
A) nitrogen treatment only 
B) biomass of aboveground plant only 
C) presence and absence of mycorrhizae 
D) nitrogen treatment and whether mycorrhizae are present

Question 8

In the nitrogen cycle,which step depends exclusively on bacteria?

Accepted Answer

A) fertilizer runoff into waterways 
B) sedimentation into lake bottoms 
C) decomposition of detritus 
D) nitrogen fixation in roots 
A) fertilizer runoff into waterways 
B) sedimentation into lake bottoms 
C) decomposition of detritus 
D) nitrogen fixation in roots

Question 9

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 incoming solar radiation is converted to heat energy. 
B) Only 1% of visible light wavelengths are absorbed by photosynthetic pigments. 
C) 50% of the sun's energy strikes large bodies of water and barren land surfaces. 
D) 99% of the solar radiation is reflected,absorbed,or scattered in the atmosphere. 
E) Only the green wavelengths of light are absorbed by plants for photosynthesis. 
A) Approximately 99% of the incoming solar radiation is converted to heat energy. 
B) Only 1% of visible light wavelengths are absorbed by photosynthetic pigments. 
C) 50% of the sun's energy strikes large bodies of water and barren land surfaces. 
D) 99% of the solar radiation is reflected,absorbed,or scattered in the atmosphere. 
E) Only the green wavelengths of light are absorbed by plants for photosynthesis.

Question 10

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

Question 11

Please use the following information to answer the questions 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.
-Which of the following correctly traces a carbon molecule in a Great Lakes forest that is invaded with non-native earthworms?

Accepted Answer

A) leaf litter → earthworm → soil → trees 
B) trees → leaf litter → earthworm → atmosphere 
C) bird → earthworm → soil → trees 
D) earthworm → fungi → leaf litter → trees 
A) leaf litter → earthworm → soil → trees 
B) trees → leaf litter → earthworm → atmosphere 
C) bird → earthworm → soil → trees 
D) earthworm → fungi → leaf litter → trees

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) Chemosynthetic prokaryotes convert all organic matter to energy. 
B) Matter can be moved between ecosystems as they are open systems. 
C) Autotrophs convert simple sugars to complex organic molecules. 
D) Matter can be lost to the environment as it is converted to energy. 
E) Heterotrophs convert light energy to non-living organic matter. 
A) Chemosynthetic prokaryotes convert all organic matter to energy. 
B) Matter can be moved between ecosystems as they are open systems. 
C) Autotrophs convert simple sugars to complex organic molecules. 
D) Matter can be lost to the environment as it is converted to energy. 
E) Heterotrophs convert light energy to non-living organic matter.

Question 13

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

Accepted Answer

A) Decomposition on the forest floor takes four to six years on average. 
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) Decomposition on the forest floor takes four to six years on average. 
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.

Question 14

What is the production efficiency of the grasshopper?

Accepted Answer

A) 70% 
B) 50% 
C) 30% 
D) 15% 
A) 70% 
B) 50% 
C) 30% 
D) 15%

Question 15

Some chemical energy is not converted to new biomass as energy is transferred between trophic levels.Which of the following best describes the fate of the unconverted energy?

Accepted Answer

A) It is all undigested and excreted as feces,so it is not passed on to higher trophic levels. 
B) It is only used by organisms to maintain essential processes like cellular respiration. 
C) It is converted during cellular respiration to heat helping the heterotroph to stay warm. 
D) It is eliminated as feces or released as heat to satisfy the second law of thermodynamics. 
E) It is recycled by decomposers to a form that is once again usable by primary producers. 
A) It is all undigested and excreted as feces,so it is not passed on to higher trophic levels. 
B) It is only used by organisms to maintain essential processes like cellular respiration. 
C) It is converted during cellular respiration to heat helping the heterotroph to stay warm. 
D) It is eliminated as feces or released as heat to satisfy the second law of thermodynamics. 
E) It is recycled by decomposers to a form that is once again usable by primary producers.

Question 16

Nitrifying bacteria participate in the nitrogen cycle mainly by

Accepted Answer

A) converting nitrogen gas to ammonia. 
B) releasing ammonium from organic compounds. 
C) converting ammonium to nitrate. 
D) incorporating nitrogen into amino acids. 
A) converting nitrogen gas to ammonia. 
B) releasing ammonium from organic compounds. 
C) converting ammonium to nitrate. 
D) incorporating nitrogen into amino acids.

Question 17

The availability of soil nutrients has a direct effect on primary productivity.Which of the following is most correct regarding non-limiting and limiting nutrients?

Accepted Answer

A) Only phosphorus acts as a limiting nutrient to global primary productivity. 
B) Adding a limiting nutrient,such as nitrogen,would decrease primary production. 
C) Increases in non-limiting nutrients result in increases in primary productivity. 
D) Nitrogen is the limiting nutrient when considering global primary production. 
E) Phosphorous is the only limiting nutrient in terrestrial primary productivity. 
A) Only phosphorus acts as a limiting nutrient to global primary productivity. 
B) Adding a limiting nutrient,such as nitrogen,would decrease primary production. 
C) Increases in non-limiting nutrients result in increases in primary productivity. 
D) Nitrogen is the limiting nutrient when considering global primary production. 
E) Phosphorous is the only limiting nutrient in terrestrial primary productivity.

Question 18

Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem?

Accepted Answer

A) the rate of decomposition in the ecosystem 
B) the production efficiency of the consumers 
C) the trophic efficiency of the ecosystem 
D) the location of the nutrient reservoirs 
A) the rate of decomposition in the ecosystem 
B) the production efficiency of the consumers 
C) the trophic efficiency of the ecosystem 
D) the location of the nutrient reservoirs

Question 19

Which of the following refers to the amount of new biomass added in a given period of time?

Accepted Answer

A) net ecosystem production 
B) net primary productivity 
C) secondary productivity 
D) trophic level efficiency 
E) gross primary productivity 
A) net ecosystem production 
B) net primary productivity 
C) secondary productivity 
D) trophic level efficiency 
E) gross primary productivity

Question 20

Which of the following statements about biogeochemical cycling is correct?

Accepted Answer

A) The phosphorus cycle includes the recycling of atmospheric phosphorus gas. 
B) The phosphorus cycle involves the weathering of rocks of marine origin. 
C) The carbon cycle incorporates carbon dioxide produced from photosynthesis. 
D) The carbon cycle always maintains a constant level of atmospheric CO2. 
A) The phosphorus cycle includes the recycling of atmospheric phosphorus gas. 
B) The phosphorus cycle involves the weathering of rocks of marine origin. 
C) The carbon cycle incorporates carbon dioxide produced from photosynthesis. 
D) The carbon cycle always maintains a constant level of atmospheric CO2.

Exam 42: Ecosystems and Energy

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?

Corn production can be limited by nitrogen levels in the soil.Some farmers reduce the need to apply ammonia to their fields by rotating corn crops with nitrogen-fixing soybean crops.Using soybeans to add nitrogen to degraded soils is an example of

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

Gross primary production in aquatic ecosystems is most likely to be limited by decreases in which of the following nutrient pairs?

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

In the nitrogen cycle,which step depends exclusively on bacteria?

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?

Which of the following is an example of an ecosystem?

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?

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

What is the production efficiency of the grasshopper?

Some chemical energy is not converted to new biomass as energy is transferred between trophic levels.Which of the following best describes the fate of the unconverted energy?

Nitrifying bacteria participate in the nitrogen cycle mainly by

The availability of soil nutrients has a direct effect on primary productivity.Which of the following is most correct regarding non-limiting and limiting nutrients?

Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem?

Which of the following refers to the amount of new biomass added in a given period of time?

Which of the following statements about biogeochemical cycling is correct?

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

Ecological Communities

Conservation Biology and Global Change

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