Photosynthetic organisms are unique to most ecosystems because they
A) synthesize organic compounds they obtain from decaying heterotrophs.
B) synthesize inorganic compounds from organic compounds.
C) use light energy to synthesize organic compounds from inorganic compounds.
D) use chemical energy to synthesize organic compounds.
E) convert light energy into matter.

C

A cow's herbivorous diet indicates that it is a(n)
A) primary consumer.
B) secondary consumer.
C) decomposer.
D) autotroph.
E) producer.

A

To recycle nutrients, an ecosystem must have, at a minimum,
A) producers.
B) producers and decomposers.
C) producers, primary consumers, and decomposers.
D) producers, primary consumers, secondary consumers, and decomposers.
E) producers, primary consumers, secondary consumers, top carnivores, and decomposers.

B

Which of the following terms encompasses all of the others?
A) heterotrophs
B) herbivores
C) carnivores
D) primary consumers
E) secondary consumers

A

Which of the following is an example of an ecosystem?
A) all of the brook trout in a 500-square-hectare 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) all of the organisms and their physical environment in a tropical rain forest

E

If the sun were to suddenly stop providing energy to Earth, most ecosystems would vanish.
Which of the following ecosystems would likely survive the longest after this hypothetical
disaster?
A) tropical rain forest
B) tundra
C) deep-sea vent community
D) grassland
E) desert

C

Which of the following is true of detritivores?
A) They recycle chemical elements directly back to primary consumers.
B) They synthesize organic molecules that are used by primary producers.
C) They convert organic materials from all trophic levels to inorganic compounds usable by
primary producers.
D) They secrete enzymes that convert the organic molecules of detritus into CO2 and H2O.
E) Some species are autotrophic, whereas others are heterotrophic.

C

The major role of detritivores in ecosystems is to
A) provide a nutritional resource for heterotrophs.
B) recycle chemical nutrients to a form capable of being used by autotrophs.
C) prevent the buildup of the organic remains of organisms, feces, and so on.
D) return energy lost to the ecosystem by other organisms.

B

The major role of detrivores in ecosystems is to
A) provide a nutritional resource for heterotrophs.
B) recycle chemical nutrients to a form capable of being used by autotrophs.
C) prevent the buildup of the inorganic remains of organisms, feces, and so on.
D) return energy lost to the ecosystem by other organisms.

B

In a typical grassland community, which of the following is the primary consumer?
A) hawk
B) snake
C) shrew
D) grasshopper
E) grass

D

Which of the following statements is true?
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.

C

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?
A) Approximately 99% of the solar radiation is converted to heat energy.
B) Only 1% of the wavelengths of visible light is absorbed by photosynthetic pigments.
C) Most solar energy strikes water and land surfaces.
D) Approximately 99% of the solar radiation is reflected.
E) Only the green wavelengths are absorbed by plants for photosynthesis.

B

What percentage of solar radiation striking a plant is converted into chemical energy?
A) 1%
B) 10%
C) 25%
D) 50%
E) 100%

A

Subtraction of which of the following will convert gross primary productivity into net
primary productivity?
A) the energy contained in the standing crop
B) the energy used by heterotrophs in respiration
C) the energy used by autotrophs in respiration
D) the energy fixed by photosynthesis
E) all solar energy

C

Which of these ecosystems accounts for the largest amount of Earth's net primary
productivity?
A) tundra
B) savanna
C) salt marsh
D) open ocean
E) tropical rain forest

D

Which of these ecosystems has the highest net primary productivity per square meter
annually?
A) savanna
B) open ocean
C) boreal forest
D) tropical rain forest
E) temperate forest

D

Which of the following is a true statement regarding mineral nutrients in soils and their
implication for primary productivity?
A) Globally, phosphorous availability is most limiting to primary productivity.
B) Adding a nonlimiting nutrient will stimulate primary productivity.
C) Adding more of a limiting nutrient will increase primary productivity, indefinitely.
D) Phosphorous is sometimes unavailable to producers due to leaching.
E) Alkaline soils are more productive than acidic soils.

D

The total biomass of photosynthetic autotrophs present in an ecosystem is known as
A) gross primary productivity.
B) standing crop.
C) net primary productivity.
D) secondary productivity.
E) trophic efficiency.

B

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?
A) Oceans contain greater concentrations of nutrients compared to other ecosystems.
B) Oceans receive a lesser amount of solar energy per unit area.
C) Oceans have the largest area of all the ecosystems on Earth.
D) Ocean ecosystems have less species diversity.
E) Oceanic producers are generally much smaller than oceanic consumers.

C

Why is net primary production (NPP) a more useful measurement to an ecosystem ecologist
than gross primary production (GPP)?
A) NPP can be expressed in energy/unit of area/unit of time.
B) NPP can be expressed in terms of carbon fixed by photosynthesis for an entire ecosystem.
C) NPP represents the stored chemical energy that will be available to consumers in the
ecosystem.
D) NPP is the same as the standing crop.
E) NPP shows the rate at which the standing crop is utilized by consumers.

C

How is net ecosystem production (NEP) typically estimated in ecosystems?
A) the ratio of producers to consumers
B) the amount of heat energy released by the ecosystem
C) the net flux of CO2 or O2 in or out of an ecosystem
D) the rate of decomposition by detritivores
E) the annual total of incoming solar radiation per unit of area

C

Aquatic primary productivity is most limited by which of the following?
A) light and nutrient availability
B) predation by primary consumers
C) increased pressure with depth
D) pollution
E) temperature

A

Aquatic ecosystems are most likely to be limited by which of the following nutrients?
A) nitrogen
B) carbon
C) potassium
D) iron
E) zinc

A

What is the primary limiting factor for aquatic productivity?
A) pressure
B) lack of nutrients
C) light availability
D) herbivores
E) competition

B

Which of the following ecosystems would likely have a larger net primary
productivity/hectare, and why?
A) open ocean because of the total biomass of photosynthetic autotrophs
B) a temperate grassland because of the small standing crop biomass that results from
consumption by herbivores and rapid decomposition
C) tropical rain forest because of the high 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

C

How is it that satellites can detect differences in primary productivity on Earth?
A) Photosynthetic organisms absorb more visible light in the 350-750 wavelengths.
B) Satellite instruments can detect reflectance patterns of the photosynthetic organisms of
different ecosystems.
C) Sensitive satellite instruments can measure the amount of NADPH produced in the
summative light reactions of different ecosystems.
D) Satellites detect differences by comparing the wavelengths of light captured and reflected by
photoautotrophs to the amount of light reaching different ecosystems.
E) Satellites detect differences by measuring the amount of water vapor emitted by transpiring
producers.

D

Which of the following lists of organisms is ranked in correct order from lowest to highest
percent in production efficiency?
A) mammals, fish, insects
B) insects, fish, mammals
C) fish, insects, mammals
D) insects, mammals, fish
E) mammals, insects, fish

A

A 3-hectare lake in the American Midwest suddenly has succumbed to an algal bloom. What
is the likely cause of eutrophication in freshwater ecosystems, such as this one?
A) increased solar radiation
B) introduction of non-native tertiary consumer fish
C) nutrient-rich runoff
D) accidental introduction of a prolific culture of algae
E) iron dust blowing into the lake

C

Approximately how many kg of carnivore biomass can be supported by a field plot
containing 1,000 kg of plant material?
A) 10,000
B) 1,000
C) 100
D) 10
E) 1

D

The amount of chemical energy in a consumer's food that is converted to its own new
biomass during a given time period is known as which of the following?
A) biomass
B) standing crop
C) biomagnification
D) primary production
E) secondary production

E

What is secondary production?
A) energy converted by secondary consumers from primary consumers
B) solar energy that is converted to chemical energy by photosynthesis
C) food that is converted to new biomass by consumers
D) energy that is not used by consumers for growth and reproduction
E) growth that takes place during the second year of life in consumers

C

How does inefficient transfer of energy among trophic levels result in the typically high
endangerment status of many top-level predators?
A) Top-level predators are destined to have small populations that are sparsely distributed.
B) Predators have relatively large population sizes.
C) Predators are more disease-prone than animals at lower trophic levels.
D) Predators have short life spans and short reproductive periods.
E) Top-level predators are more likely to be stricken with parasites.

A

Trophic efficiency is
A) the ratio of net secondary production to assimilation of primary production.
B) the percentage of production transferred from one trophic level to the next.
C) a measure of how nutrients are cycled from one trophic level to the next.
D) usually greater than production efficiencies.
E) about 90% in most ecosystems.

B

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
2,600 J for cellular respiration. What is the production efficiency of this owl?
A) 0.02%
B) 1%
C) 4%
D) 10%
E) 40%

C

Why does a vegetarian leave a smaller ecological footprint than an omnivore?
A) Fewer animals are slaughtered for human consumption.
B) There is an excess of plant biomass in all terrestrial ecosystems.
C) Vegetarians need to ingest less chemical energy than omnivores.
D) Vegetarians require less protein than do omnivores.
E) Eating meat is an inefficient way of acquiring photosynthetic productivity.

E

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
A) secondary consumers and top carnivores require less energy than producers.
B) at each step, energy is lost from the system because of the second law of thermodynamics.
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

Which of the following is primarily responsible for limiting the number of trophic levels in
most ecosystems?
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 trophic levels is almost always less than 20% efficient.

E

Which trophic level is most vulnerable to extinction?
A) producer level
B) primary consumer level
C) secondary consumer level
D) tertiary consumer level
E) decomposer level

D

Which statement best describes what ultimately happens to the chemical energy that is not
converted to new biomass in the process of energy transfer between trophic levels in an
ecosystem?
A) It is undigested and winds up in the feces and is not passed on to higher trophic levels.
B) It is used by organisms to maintain their life processes through the reactions of cellular
respiration.
C) Heat produced by cellular respiration is used by heterotrophs to thermoregulate.
D) It is eliminated as feces or is dissipated into space as heat in accordance with the second law
of thermodynamics.
E) It is recycled by decomposers to a form that is once again usable by primary producers.

D

Consider the food chain grass → grasshopper → mouse → snake → hawk. How much of the
chemical energy fixed by photosynthesis of the grass (100%) is available to the hawk?
A) 0.01%
B) 0.1%
C) 1%
D) 10%
E) 60%

A

If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps
involving humans, starting from phytoplankton to zooplankton to fish to seals to polar bears,
then which of the following could be true?
A) Polar bears can provide more food for humans than seals can.
B) The total biomass of the fish is lower than that of the seals.
C) Seal meat probably contains the highest concentrations of fat-soluble toxins.
D) Seal populations are larger than fish populations.
E) The fish can potentially provide more food for humans than the seal meat can.

E