Question 1

In the equation NPP = GPP - respiration, the term "GPP" is best defined by total
A) plant biomass produced.
B) plant and animal biomass produced.
C) carbon fixed by primary producers.
D) carbon fixed by producers and consumers.
E) carbon used by producers in all activities, including respiration.

Accepted Answer

GPP (Gross Primary Productivity) refers to the total amount of carbon fixed by primary producers during photosynthesis. It does not include the carbon used by producers in all activities including respiration or biomass produced by animals. Therefore, option C is the correct choice.

Question 2

In which situation would bacteria be most likely to obtain energy through chemosynthesis, rather than photosynthesis?
A) At the ocean surface
B) At the soil surface
C) In an estuary with frequent mixing of water
D) Deep in the soil where no light penetrates
E) In a farm field that undergoes frequent plowing

Accepted Answer

Bacteria are more likely to obtain energy through chemosynthesis rather than photosynthesis when they are in an environment where light cannot penetrate, as they cannot undergo photosynthesis without light. Deep in the soil where no light penetrates would be the most likely situation for this to occur.

Question 3

Compared with the open ocean ecosystem, the continental shelf ecosystem
A) has higher net primary productivity on a per area basis.
B) covers more surface area.
C) has higher net primary productivity on a global basis.
D) is productive down to a greater depth.
E) is less limited by nutrients.

Accepted Answer

The continental shelf ecosystem has higher net primary productivity on a per area basis compared to the open ocean ecosystem. This is due to the fact that the continental shelf ecosystem is shallower and has more access to sunlight, which is necessary for photosynthesis to occur.

Question 4

Compared with ocean productivity, land productivity
A) varies more with latitude and is much higher.
B) varies more with latitude and is much lower.
C) varies less with latitude and is much higher.
D) varies less with latitude and is much lower.
E) does not vary with latitude and is much lower.

Accepted Answer

Land productivity varies more with latitude due to differences in climate, vegetation, and sunlight, and it is generally higher than ocean productivity because terrestrial ecosystems, especially forests and grasslands, have higher biomass and primary productivity.

Question 5

When CO₂ from the atmosphere dissolves into the oceans, it changes ocean water by A) increasing its temperature. B) decreasing its temperature. C) increasing its acidity. D) decreasing its acidity. E) increasing its salinity.

Accepted Answer

When CO₂ dissolves into the oceans, it hydrolyzes to form carbon dioxide and hydrogen sulfide. This reaction increases the acidity of the ocean water, also known as ocean acidification.

Question 6

A bacterial species lives deep in the ocean, where chemicals including hydrogen sulfide and methane seep out of superheated magma.The bacteria obtain their energy by breaking down these chemicals and building organic chemicals from them.They are carrying out which biological process?
A) Chemosynthesis
B) Photosynthesis
C) Secondary production
D) Heterotrophy
E) Metabolism

Accepted Answer

The bacterial species is obtaining energy by breaking down chemicals and building organic compounds from them, which is characteristic of chemosynthesis. This process is different from photosynthesis, which involves obtaining energy from sunlight, and heterotrophy, which involves obtaining energy from consuming other organisms. Secondary production and metabolism are broader biological concepts that do not specifically apply to this scenario.

Question 7

Which statement best describes a key difference between movement of energy and movement of nutrients through an ecosystem?
A) Nutrients always move rapidly through an ecosystem; energy always moves slowly.
B) The same energy is used over and over; nutrients move through a system and do not return.
C) The same nutrients are used over and over; energy moves through a system, and some is lost as heat.
D) The amount of energy determines the amount of production that can occur; the amount of nutrients is not relevant.
E) The amount of nutrients determines the amount of production that can occur; the amount of energy is not relevant.

Accepted Answer

Energy moves through an ecosystem in a unidirectional flow, meaning that it is not recycled within the system and some is lost as heat. On the other hand, nutrients are recycled within the system and do not move in a unidirectional flow like energy.

Question 8

Algal beds contribute very little to Earth's total net primary production because they are limited by
A) insufficient light.
B) oxygen depletion.
C) insufficient phosphorus.
D) being at very low latitudes.
E) being a tiny fraction of Earth's surface.

Accepted Answer

Algal beds, despite their high productivity per unit area, cover a very small fraction of Earth's surface compared to terrestrial ecosystems and the vast open oceans. This limited coverage means their total contribution to Earth's net primary productivity is relatively small.

Question 9

An organism obtains its nutrients from inorganic chemicals present in soil, water, and air.It incorporates these materials into its tissues in the form of organic compounds.This organism is a(n)
A) autotroph.
B) heterotroph.
C) detritivore.
D) decomposer.
E) predator.

Accepted Answer

An autotroph is an organism that can synthesize its own food from inorganic substances using energy from the sun or other sources. This organism is obtaining its nutrients from inorganic chemicals, which are then incorporated into organic compounds, indicating that it is an autotroph.

Question 10

Both desert and tundra have very low NPP values.What factor or factors determine NPP values in these two biomes?
A) Both deserts and tundra are limited by temperature.
B) Both deserts and tundra are limited by precipitation.
C) Deserts are limited by precipitation and tundra by temperature.
D) Deserts are limited by temperature and tundra by precipitation.
E) Deserts and tundra are limited by nutrients, not by temperature or precipitation.

Accepted Answer

Deserts are limited by precipitation as they receive very little rainfall, while tundra is limited by temperature as it experiences very cold conditions throughout the year. Both factors, precipitation and temperature, can limit the photosynthetic activity of plants and, therefore, their NPP values.

Question 11

Refer to the figure.  The algal bed and coral reef ecosystem type and the swamp and stream ecosystem type each have an average net primary productivity close to that of tropical rainforests.However, each makes up a much smaller percentage of Earth's net primary production than do rainforests.What factor accounts for this difference?
A) Latitude with tropical rainforest ecosystems
B) Percent of Earth's surface with tropical rainforest ecosystems
C) Type of ecosystem
D) Average temperature
E) Average precipitation

Accepted Answer

The question states that the algal bed and coral reef ecosystem type and the swamp and stream ecosystem type have an average net primary productivity close to that of tropical rainforests. However, they make up a much smaller percentage of Earth's net primary production than do rainforests. This can be attributed to the fact that there is a smaller percent of Earth's surface area occupied by these ecosystems compared to tropical rainforests. Therefore, the factor that accounts for the difference in net primary production is the percent of Earth's surface with tropical rainforest ecosystems (choice B).

Question 12

Research ecologists often specialize in one level of ecology.Which question would most likely be studied by a Yellowstone National Park ecologist specializing in biogeochemical cycles in ecosystems?
A) What is the sex ratio of the elk living in the park?
B) How does nitrogen move among the organisms, soil, water, air, and rocks of the park?
C) How does the reintroduction of wolves influence other large mammal populations in the park?
D) What types of species interactions occur among the major species in the park's food webs?
E) What geological history led to the development of the park's environment?

Accepted Answer

A Yellowstone National Park ecologist specializing in biogeochemical cycles in ecosystems would study the movement of elements such as nitrogen, carbon, and phosphorus through living and nonliving components of the ecosystem. They would be interested in how these nutrients are utilized and recycled by different organisms and processes in the park. Option B directly addresses this inquiry. The other options are not related to biogeochemical cycles.

Question 13

Which of these land ecosystems would be expected to have the highest total net primary productivity?
A) Tundra
B) Boreal forest
C) Temperate deciduous forest
D) Temperate grassland
E) Tropical rainforest

Accepted Answer

The tropical rainforest has the highest net primary productivity due to year-round warm temperature and high rainfall that promotes high levels of photosynthesis and nutrient cycling.

Question 14

A major difference between primary and secondary production in ecosystems is that secondary production involves
A) using metabolism to release nutrients for use, whereas primary production does not.
B) obtaining energy from organic, rather than inorganic, compounds.
C) obtaining energy from sunlight, rather than from chemical compounds.
D) plants, seaweeds, and algae, whereas primary production involves animals.
E) production of different classes of organic compounds than primary production does.

Accepted Answer

Primary production involves the conversion of inorganic compounds into organic compounds using energy from sunlight, whereas secondary production involves obtaining energy from organic compounds.

Question 15

In which situation are humans not directly affecting the NPP of aquatic ecosystems by altering nutrient concentrations? That is, which situation is natural, rather than caused by humans? A) Rising CO₂ from global warming increases NPP of ocean phytoplankton. B) Phytoplankton blooms occur when iron sulfite is added to ocean water. C) Artificial fertilizers from land cause plankton blooms in the Gulf of Mexico. D) Sewage and wastewater cause eutrophication in Lake Erie. E) High nitrogen levels in the Pacific Ocean keep NPP high.

Accepted Answer

High nitrogen levels in the Pacific Ocean keep NPP high is a natural situation, rather than caused by humans.

Question 16

Which description does not fit the definition of an ecosystem study?
A) The transformation of energy through a group of forest-floor species
B) The cycling of carbon through a group of soil bacteria on the forest floor
C) Measurement of primary production by all producers in a large forest
D) Atmospheric nitrogen fixation by plants in a forest environment
E) Competitive and cooperative interactions among forest-floor beetle species

Accepted Answer

Ecosystem studies focus on energy flow and nutrient cycling, not on species interactions like competition or cooperation.

Question 17

Organisms in an estuary, including phytoplankton, seagrasses, crustaceans, and mollusks, are all exposed to increasing acidity as atmospheric CO₂ levels rise.What effect does the increased acidity likely have on these organisms? A) All organisms are adversely affected and some die. B) All organisms are unaffected and live and reproduce normally. C) Phytoplankton and seagrasses decrease photosynthesis, and crustaceans and mollusks reproduce less. D) Phytoplankton and seagrasses increase photosynthesis, and crustaceans and mollusks reproduce more. E) Phytoplankton and seagrasses increase photosynthesis, and crustaceans and mollusks have weaker shells.

Accepted Answer

Increased acidity, primarily due to rising CO2 levels, can lead to weaker shells in crustaceans and mollusks because it reduces the availability of carbonate ions needed for shell formation. Phytoplankton and seagrasses might increase photosynthesis due to higher CO2 levels, acting as a carbon source.

Question 18

Which is the correct order of forest types, from lowest to highest total NPP.
A) Tropical, boreal, temperate deciduous
B) Tropical, temperate deciduous, boreal
C) Boreal, tropical, temperate deciduous
D) Boreal, temperate deciduous, tropical
E) Temperate deciduous, boreal, tropical

Accepted Answer

Boreal forests have the lowest Net Primary Productivity (NPP) due to their cold climates, followed by temperate deciduous forests with moderate NPP, and tropical forests have the highest NPP because of their warm temperatures and high levels of precipitation.

Question 19

An upwelling zone off the coast of Peru, in South America, has a very high net productivity.The factor that probably contributes most to the region's high NPP is its
A) low latitude.
B) arid regions on the coast.
C) long distance from the coast.
D) increased nutrients from deep water.
E) small geographic area.

Accepted Answer

The upwelling zone off the coast of Peru is known for the nutrient-rich water that rises from deep ocean currents. This nutrient-rich water supports photosynthetic organisms, such as phytoplankton, which form the base of the marine food web. The increased nutrients from deep water, therefore, are the most significant factor contributing to the region's high net productivity.

Question 20

Two tropical forest regions receive extremely high rainfall (more than 400 cm/yr).The NPP of forest A is much higher than the NPP of forest B.Which factor is likely most associated with the difference in NPP?
A) Forest A has more cloud cover than forest B.
B) Forest A has less cloud cover than forest B.
C) Forest A is at a higher latitude than forest B.
D) Forest A is at a lower latitude than forest B.
E) Forest A has more flooding than forest B.

Accepted Answer

Forest A has less cloud cover than forest B, which could allow for more direct sunlight to reach the forest floor and promote higher photosynthesis rates, leading to higher NPP.

Quiz 57: Ecosystems

In the equation NPP = GPP - respiration, the term "GPP" is best defined by total

In which situation would bacteria be most likely to obtain energy through chemosynthesis, rather than photosynthesis?

Compared with the open ocean ecosystem, the continental shelf ecosystem

Compared with ocean productivity, land productivity

When CO₂ from the atmosphere dissolves into the oceans, it changes ocean water by

A bacterial species lives deep in the ocean, where chemicals including hydrogen sulfide and methane seep out of superheated magma.The bacteria obtain their energy by breaking down these chemicals and building organic chemicals from them.They are carrying out which biological process?

Which statement best describes a key difference between movement of energy and movement of nutrients through an ecosystem?

Algal beds contribute very little to Earth's total net primary production because they are limited by

An organism obtains its nutrients from inorganic chemicals present in soil, water, and air.It incorporates these materials into its tissues in the form of organic compounds.This organism is a(n)

Both desert and tundra have very low NPP values.What factor or factors determine NPP values in these two biomes?

Research ecologists often specialize in one level of ecology.Which question would most likely be studied by a Yellowstone National Park ecologist specializing in biogeochemical cycles in ecosystems?

Which of these land ecosystems would be expected to have the highest total net primary productivity?

A major difference between primary and secondary production in ecosystems is that secondary production involves

In which situation are humans not directly affecting the NPP of aquatic ecosystems by altering nutrient concentrations? That is, which situation is natural, rather than caused by humans?

Which description does not fit the definition of an ecosystem study?

Organisms in an estuary, including phytoplankton, seagrasses, crustaceans, and mollusks, are all exposed to increasing acidity as atmospheric CO₂ levels rise.What effect does the increased acidity likely have on these organisms?

Which is the correct order of forest types, from lowest to highest total NPP.

An upwelling zone off the coast of Peru, in South America, has a very high net productivity.The factor that probably contributes most to the region's high NPP is its

Two tropical forest regions receive extremely high rainfall (more than 400 cm/yr) .The NPP of forest A is much higher than the NPP of forest B.Which factor is likely most associated with the difference in NPP?