Question 1

More than half of the water from the hydrologic cycle that travels over and through the land eventually reaches the ocean from which source?

Accepted Answer

A)  Rainfall 
B)  Coastal runoff 
C)  Groundwater flow 
D)  Evapotranspiration 
E)  Earth's largest rivers 
A)  Rainfall 
B)  Coastal runoff 
C)  Groundwater flow 
D)  Evapotranspiration 
E)  Earth's largest rivers

Question 2

Microbes, primarily bacteria, are responsible for all of the following aspects of the nitrogen cycle except

Accepted Answer

A)  biological nitrogen fixation. 
B)  nitrification. 
C)  nitrate reduction. 
D)  denitrification. 
E)  industrial nitrogen fixation. 
A)  biological nitrogen fixation. 
B)  nitrification. 
C)  nitrate reduction. 
D)  denitrification. 
E)  industrial nitrogen fixation.

Question 3

Refer to the graph.   Which conclusion can be drawn from the graph about the value of sustainable ecosystems, compared with the value of those converted entirely to human use?

Accepted Answer

A)  Their value is only slightly greater. 
B)  Their value is generally several times greater. 
C)  Their value is generally several times less. 
D)  The values shown are estimates and are therefore meaningless. 
E)  The values shown are meaningless because ecosystems have no dollar value. 
A)  Their value is only slightly greater. 
B)  Their value is generally several times greater. 
C)  Their value is generally several times less. 
D)  The values shown are estimates and are therefore meaningless. 
E)  The values shown are meaningless because ecosystems have no dollar value.

Question 4

A hare population ingests local plants and assimilates a percentage of the plant biomass (assimilation = ingestion - excretion).The hares use energy in metabolism as they move, grow, and maintain body temperature.The body tissue they make and the baby hares they produce are available to the local fox population, the main predator of hares.Compared with the amount of energy transferred from plants to hares, the amount transferred from hares to foxes is

Accepted Answer

A)  much less. 
B)  a little less. 
C)  much more. 
D)  a lot more. 
E)  about the same. 
A)  much less. 
B)  a little less. 
C)  much more. 
D)  a lot more. 
E)  about the same.

Question 5

During photosynthesis, carbon in the atmosphere (in the form of CO2) is transferred to plants, where it is turned into organic plant biomass.Some of the carbon also enters the soil, and some is returned to the atmosphere through respiration.Which parts of this interaction would be considered pools, and which would be fluxes?

Accepted Answer

A)  The atmosphere is a pool; the plants and soil are fluxes. 
B)  The atmosphere and plants are pools; the soil is a flux. 
C)  The atmosphere, plants, and soil are pools; the movements between them are fluxes. 
D)  The movements between atmosphere, plants, and soil are pools; the atmosphere, plants, and soil are fluxes. 
E)  Movements of carbon to and from the atmosphere are fluxes; movement into the soil is a pool. 
A)  The atmosphere is a pool; the plants and soil are fluxes. 
B)  The atmosphere and plants are pools; the soil is a flux. 
C)  The atmosphere, plants, and soil are pools; the movements between them are fluxes. 
D)  The movements between atmosphere, plants, and soil are pools; the atmosphere, plants, and soil are fluxes. 
E)  Movements of carbon to and from the atmosphere are fluxes; movement into the soil is a pool.

Question 6

The average net primary production (NPP) per square meter is greatest in the _______ ecosystem, and the greatest contribution to Earth's total primary production is made by the _______ ecosystem.

Accepted Answer

A)  tropical rainforest; tropical rainforest 
B)  algal beds and coral reefs; algal beds and coral reefs 
C)  tropical rainforest; open ocean 
D)  algal beds and coral reefs; open ocean 
E)  open ocean; open ocean 
A)  tropical rainforest; tropical rainforest 
B)  algal beds and coral reefs; algal beds and coral reefs 
C)  tropical rainforest; open ocean 
D)  algal beds and coral reefs; open ocean 
E)  open ocean; open ocean

Question 7

A major distinction between decomposition and mineralization is that decomposition

Accepted Answer

A)  occurs after mineralization. 
B)  is a biological process, while mineralization is a chemical process. 
C)  is a chemical process, while mineralization is a biological process. 
D)  first breaks organic matter into smaller particles, which then undergo mineralization. 
E)  is part of energy flow, while mineralization is part of biogeochemical cycling. 
A)  occurs after mineralization. 
B)  is a biological process, while mineralization is a chemical process. 
C)  is a chemical process, while mineralization is a biological process. 
D)  first breaks organic matter into smaller particles, which then undergo mineralization. 
E)  is part of energy flow, while mineralization is part of biogeochemical cycling.

Question 8

Most of the biomass in a grassland is found in _______; most of the biomass in the open ocean is in _______.

Accepted Answer

A)  primary consumers; primary producers 
B)  primary producers; primary consumers 
C)  primary consumers; secondary consumers 
D)  secondary consumers; primary consumers 
E)  primary producers; secondary consumers 
A)  primary consumers; primary producers 
B)  primary producers; primary consumers 
C)  primary consumers; secondary consumers 
D)  secondary consumers; primary consumers 
E)  primary producers; secondary consumers

Question 9

An ecosystem has very high productivity, abundant rain, and long growing seasons with relatively high temperatures.Strands in its food webs have no more than three or four trophic levels.Which of these factors is least likely to affect the number of trophic levels in the food web?

Accepted Answer

A)  Energy is lost at every trophic level, so the web can only support a limited number of levels. 
B)  Top predators limit the number of trophic levels because they have no predators. 
C)  Humans control all major food webs and maintain the number of levels by predation. 
D)  Having fewer levels makes it easier for a web to recover after a disturbance. 
E)  The presence of omnivores limits NPP and possibly the number of trophic levels. 
A)  Energy is lost at every trophic level, so the web can only support a limited number of levels. 
B)  Top predators limit the number of trophic levels because they have no predators. 
C)  Humans control all major food webs and maintain the number of levels by predation. 
D)  Having fewer levels makes it easier for a web to recover after a disturbance. 
E)  The presence of omnivores limits NPP and possibly the number of trophic levels.

Question 10

Industrial nitrogen fixation results in all of the following effects except

Accepted Answer

A)  production of ammonia fertilizers. 
B)  production of nitrous oxide gas (N2O). 
C)  eutrophication of coastal waters. 
D)  increase in ozone and smog. 
E)  production of DMSP. 
A)  production of ammonia fertilizers. 
B)  production of nitrous oxide gas (N2O). 
C)  eutrophication of coastal waters. 
D)  increase in ozone and smog. 
E)  production of DMSP.

Question 11

The shortest residence time for water in pools of the hydrologic cycle occurs in

Accepted Answer

A)  aquifers. 
B)  lakes. 
C)  rivers. 
D)  glaciers. 
E)  oceans. 
A)  aquifers. 
B)  lakes. 
C)  rivers. 
D)  glaciers. 
E)  oceans.

Question 12

Refer to the figure.   Due to rising atmospheric CO2 levels, ocean temperatures are increasing and CO2 dissolving in oceans is causing increased acidification.Omnivores (crustaceans and snails) in an estuarine food web in Sweden feed on herbivores, macroalgae, and microalgae.Herbivores feed on microalgae, which compete with macroalgae for light.Christian Alsterberg and colleagues analyzed how these three groups reacted to ocean warming and acidification, with and without the presence of omnivores.According to the graphs, which group(s) show(s) a significant increase when CO2 and temperature are increased and omnivores are removed?

Accepted Answer

A)  Benthic microalgae only 
B)  Macroalgae only 
C)  Herbivores only 
D)  Benthic microalgae and macroalgae 
E)  Macroalgae and herbivores 
A)  Benthic microalgae only 
B)  Macroalgae only 
C)  Herbivores only 
D)  Benthic microalgae and macroalgae 
E)  Macroalgae and herbivores

Question 13

This food chain in a California river resulted in almost no algae present in the summer.   However, when trout were removed from the food chain, algae growth increased 100-fold, and the river was carpeted with green algal mats.Briefly explain why this change occurred.

Accepted Answer

In top-down ecosystem control, the troph

Question 14

What factor accounts for most of the loss of energy between trophic levels?

Accepted Answer

A)  Reproduction 
B)  Growth 
C)  Respiration 
D)  Predation 
E)  Herbivory 
A)  Reproduction 
B)  Growth 
C)  Respiration 
D)  Predation 
E)  Herbivory

Question 15

A large pond receives sewage runoff from a cattle feedlot and fertilizer runoff from surrounding fields.The runoff contains large quantities of nitrogen and phosphorus.The pond undergoes an algal bloom.The algae die off and are decomposed by bacteria, which depletes the pond's oxygen content.Fish and invertebrates begin to die.What process is the pond undergoing, and changes in what limiting factor or factors initiated the process?

Accepted Answer

A)  Eutrophication; nitrogen only 
B)  Eutrophication; nitrogen, phosphorus, or both 
C)  Trophic efficiency; phosphorus only 
D)  Trophic efficiency; nitrogen, phosphorus, or both 
E)  Biogeochemical cycling; nitrogen only 
A)  Eutrophication; nitrogen only 
B)  Eutrophication; nitrogen, phosphorus, or both 
C)  Trophic efficiency; phosphorus only 
D)  Trophic efficiency; nitrogen, phosphorus, or both 
E)  Biogeochemical cycling; nitrogen only

Question 16

Refer to the figure.   Based on the values in the figure plus your understanding of the hydrologic cycle, what effects do you think rapid melting of ice and snow would have on the cycle? What pools and fluxes would be most affected, and how would they be affected?

Accepted Answer

The melting of ice and snow on land resu

Question 17

Primary producers in an ecosystem obtain their energy through

Accepted Answer

A)  photosynthesis or chemosynthesis. 
B)  photosynthesis or metabolism of organic compounds. 
C)  chemosynthesis or metabolism of organic compounds. 
D)  photosynthesis or metabolism of inorganic compounds. 
E)  chemosynthesis or metabolism of inorganic compounds. 
A)  photosynthesis or chemosynthesis. 
B)  photosynthesis or metabolism of organic compounds. 
C)  chemosynthesis or metabolism of organic compounds. 
D)  photosynthesis or metabolism of inorganic compounds. 
E)  chemosynthesis or metabolism of inorganic compounds.

Question 18

The whole lake fertilization experiments conducted by David Schindler and colleagues in Ontario, Canada, did all of the following except

Accepted Answer

A)  trigger a campaign to ban phosphates in detergents. 
B)  involve controlled experiments in natural ecosystems. 
C)  identify phosphorus as the major cause of cyanobacteria and phytoplankton blooms. 
D)  lead to recommendations to remove phosphates from water during sewage treatment. 
E)  lead to the conclusion that nitrogen and carbon were not required for algal growth. 
A)  trigger a campaign to ban phosphates in detergents. 
B)  involve controlled experiments in natural ecosystems. 
C)  identify phosphorus as the major cause of cyanobacteria and phytoplankton blooms. 
D)  lead to recommendations to remove phosphates from water during sewage treatment. 
E)  lead to the conclusion that nitrogen and carbon were not required for algal growth.

Question 19

The average NPP value for a region of ocean is 100 g C/m2/year.The average NPP for a tropical forest is 2,200 g C/m2/year.Yet oceans account for 24 percent of the world's total NPP, while tropical forests account for only 22 percent.What factor accounts for the discrepancy in average value and percentage of NPP for these two ecosystems?

Accepted Answer

A)  Area covered by oceans is much greater than area covered by tropical forests. 
B)  Ocean NPP measurements are much less accurate than land measurements. 
C)  Ocean NPP is measured by depth instead of area, which dilutes the measurements. 
D)  Ocean NPP measurements have respiration subtracted; land measurements do not. 
E)  The two measurements were made at very different latitudes. 
A)  Area covered by oceans is much greater than area covered by tropical forests. 
B)  Ocean NPP measurements are much less accurate than land measurements. 
C)  Ocean NPP is measured by depth instead of area, which dilutes the measurements. 
D)  Ocean NPP measurements have respiration subtracted; land measurements do not. 
E)  The two measurements were made at very different latitudes.

Question 20

Rising global temperatures increase the rate of evaporation.The warmer air also holds more moisture.These changing factors are most likely to directly affect which process in the hydrologic cycle?

Accepted Answer

A)  Precipitation 
B)  Runoff 
C)  Groundwater deposition 
D)  Increase in soil moisture 
E)  Increased deposition of water in oceans 
A)  Precipitation 
B)  Runoff 
C)  Groundwater deposition 
D)  Increase in soil moisture 
E)  Increased deposition of water in oceans

Exam 57: Ecosystems

More than half of the water from the hydrologic cycle that travels over and through the land eventually reaches the ocean from which source?

Microbes, primarily bacteria, are responsible for all of the following aspects of the nitrogen cycle except

Refer to the graph. Which conclusion can be drawn from the graph about the value of sustainable ecosystems, compared with the value of those converted entirely to human use?

The average net primary production (NPP) per square meter is greatest in the _______ ecosystem, and the greatest contribution to Earth's total primary production is made by the _______ ecosystem.

A major distinction between decomposition and mineralization is that decomposition

Most of the biomass in a grassland is found in _______; most of the biomass in the open ocean is in _______.

An ecosystem has very high productivity, abundant rain, and long growing seasons with relatively high temperatures.Strands in its food webs have no more than three or four trophic levels.Which of these factors is least likely to affect the number of trophic levels in the food web?

Industrial nitrogen fixation results in all of the following effects except

The shortest residence time for water in pools of the hydrologic cycle occurs in

This food chain in a California river resulted in almost no algae present in the summer. However, when trout were removed from the food chain, algae growth increased 100-fold, and the river was carpeted with green algal mats.Briefly explain why this change occurred.

What factor accounts for most of the loss of energy between trophic levels?

Refer to the figure. Based on the values in the figure plus your understanding of the hydrologic cycle, what effects do you think rapid melting of ice and snow would have on the cycle? What pools and fluxes would be most affected, and how would they be affected?

Primary producers in an ecosystem obtain their energy through

The whole lake fertilization experiments conducted by David Schindler and colleagues in Ontario, Canada, did all of the following except

Rising global temperatures increase the rate of evaporation.The warmer air also holds more moisture.These changing factors are most likely to directly affect which process in the hydrologic cycle?

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons, Glia, and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

Populations

Species Interactions

Communities

A Changing Biosphere

Filters

The average net primary production (NPP) per square meter is greatest in the _ ecosystem, and the greatest contribution to Earth's total primary production is made by the _ ecosystem.

Most of the biomass in a grassland is found in _; most of the biomass in the open ocean is in _.