Campbell Biology in Focus, 2e (Urry)
Chapter 42 Ecosystems and Energy
42.1 Multiple-Choice Questions
1) In ecosystems, why is the term cycling used to describe the transfer of chemical elements,
whereas the term flow is used for energy exchange?
A) Chemical elements are repeatedly used, but energy flows through and out of ecosystems.
B) Photosynthesis and feeding relationships result in transforming chemical elements, but not
energy.
C) Chemical elements are transferred into ecosystems from other ecosystems, but energy is only
transferred within a single ecosystem.
D) In an ecosystem, the total amount of chemical elements does not change, whereas the total
amount of energy can change.
2) Which statement most accurately describes how matter and energy are used in ecosystems?
A) Matter flows through ecosystems; energy cycles within ecosystems.
B) Energy flows through ecosystems; matter cycles within and through ecosystems.
C) Energy can be converted into matter; matter cannot be converted into energy.
D) Matter can be converted into energy; energy cannot be converted into matter.
E) Matter is used in ecosystems; energy is not.
3) 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?
A) Chemoautotrophic organisms can convert matter to energy.
B) Ecosystems are open systems; therefore, matter can be moved in/out of an ecosystem from/to
another ecosystem.
C) Photosynthetic organisms convert sugars to more complex organic molecules.
D) Detritivores convert matter to energy.
E) Heterotrophs convert heat to energy.
4) 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.
5) A cow’s herbivorous diet indicates that it is a(n)
A) primary consumer.
B) secondary consumer.
C) decomposer.
D) autotroph.
E) producer.
6) 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.
7) Which of the following terms encompasses all of the others?
A) heterotrophs
B) herbivores
C) carnivores
D) primary consumers
E) secondary consumers
8) 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
9) 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 hydrothermal vent community
D) grassland
E) desert
10) Which of the following is true of detritivores?
A) They synthesize organic molecules that are used by primary producers.
B) They convert organic materials from all trophic levels to inorganic compounds usable by
primary producers.
C) They secrete enzymes that convert the organic molecules of detritus into CO2 and H2O.
D) Some species are autotrophic, whereas others are heterotrophic.
11) 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.
12) Which of the following statements is true?
A) The trophic level that ultimately supports all others consists of detritivores.
B) Consumers can exist in an ecosystem without primary producers.
C) Chemoautotrophic prokaryotes near deep-sea vents are primary producers.
D) No losses of energy occur from primary producers in an ecosystem.
13) 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.
14) What percentage of solar radiation striking a plant is converted into chemical energy?
A) 1%
B) 10%
C) 25%
D) 50%
E) 100%
15) 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
16) 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
17) 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
18) Which of the following is a true statement regarding mineral nutrients in soils and their
implication for primary productivity?
A) Globally, only phosphorus availability is most limiting to primary productivity.
B) Adding a non-limiting nutrient will stimulate primary productivity.
C) Adding more of a limiting nutrient will increase primary productivity regardless of other
nutrient availability.
D) Phosphorus is sometimes unavailable to producers due to leaching.
E) Alkaline soils are more productive than acidic soils.
19) 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.
20) 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.
21) 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 per unit of area per 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.
22) 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
23) 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
24) Aquatic ecosystems are most likely to be limited by which of the following nutrients?
A) nitrogen
B) carbon
C) potassium
D) iron
E) zinc
25) What is the primary limiting factor for aquatic productivity?
A) pressure
B) lack of nutrients
C) light availability
D) presence of herbivores
E) competition
26) 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 long growing season and large amount of leaf surface area
D) a cave, due to the lack of photosynthetic autotrophs
E) tundra, because of the incredibly rapid period of growth during the summer season
27) How is it that satellites can detect differences in primary productivity on Earth?
A) Photosynthetic organisms absorb more visible light in the 350- to 750-nm 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.
28) Which of the following lists of organisms is ranked in correct order from lowest to highest
production efficiency?
A) mammals, fish, insects
B) insects, fish, mammals
C) fish, insects, mammals
D) insects, mammals, fish
E) mammals, insects, fish
29) A 3-hectare lake in the American Midwest suddenly has succumbed to an algal bloom. What
is the likely cause of eutrophication in this lake?
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
30) Approximately how many kilograms of secondary consumer 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
31) 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) primary production
D) secondary production
32) 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) chemical energy in 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
33) 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 restricted to 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.
34) 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.
35) 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%
36) Why does a vegetarian leave a smaller ecological footprint than a person who eats meat?
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.
37) 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) the accumulation of toxic materials in tissues of animals limits the secondary consumers and
top carnivores.
E) top carnivores and secondary consumers have a more general diet than primary producers.
38) 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.
39) Which trophic level is most vulnerable to extinction?
A) milkweed plants
B) monarch caterpillars that eat milkweed plants
C) goldfinches that eat monarch caterpillars
D) golden eagles that eat goldfinches
E) inky cap fungus that breaks down plant material
40) 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) All of it is undigested and winds up in the feces and is not passed on to higher trophic levels.
B) It is only 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.
41) 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%
42) If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps
involving humans, moving 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.
43) Nitrogen is available to plants mostly in the form of
A) N2 in the atmosphere.
B) nitrite ions in the soil.
C) uric acid from animal excretions.
D) nucleic acids from decomposing plants and animals.
E) nitrate and ammonium ions in the soil.
44) Which of the following locations is the main reservoir for nitrogen in Earth’s nitrogen cycle?
A) atmosphere
B) sedimentary bedrock
C) fossilized plant and animal remains (coal, oil, and natural gas)
D) plant and animal biomass
E) soil
45) Which of the following locations is the largest reservoir for carbon in the carbon cycle?
A) atmosphere
B) sedimentary rocks
C) fossilized plant and animal remains (coal, oil, and natural gas)
D) plant and animal biomass
46) In the nitrogen cycle, the organisms that replenish the atmosphere with N2 are
A) mycorrhizal fungi.
B) nitrifying bacteria.
C) denitrifying bacteria.
D) nitrogen-fixing bacteria.
47) How does phosphorus normally enter ecosystems?
A) as a product from cellular respiration
B) as a product from photosynthesis
C) from rock weathering
D) as atmospheric phosphorus gas
48) Which of the following statements about biogeochemical cycling is correct?
A) The phosphorus cycle involves the recycling of atmospheric phosphorus.
B) The phosphorus cycle involves the weathering of rocks.
C) The carbon cycle is a localized cycle that primarily involves the burning of fossil fuels.
D) The carbon cycle has maintained a constant atmospheric concentration of CO2 for the past
million years.
E) The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic
components of the ecosystem.
49) Why do logged tropical rain forests typically have nutrient-poor soils?
A) Tropical bedrock contains little phosphorus.
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.
50) In the nitrogen cycle, which step depends exclusively on prokaryotes?
A) runoff into waterways
B) sedimentation into lake bottoms
C) decomposition of detritus
D) fixation in root nodules
51) Rain falls on an agricultural field after a farmer has harvested the corn. Which
biogeochemical cycles are involved when runoff from the field flows into a nearby stream?
A) only carbon and water
B) only water and nitrogen
C) only carbon, nitrogen, and phosphorus
D) only water, nitrogen, and phosphorus
52) What is the first step in the restoration of an extremely degraded ecosystem?
A) to restore the physical structure
B) to restore native species that have been extirpated due to disturbance
C) to remove competitive invasive species
D) to identify the limiting factors of the producers
E) to remove toxic pollutants
53) What is the goal of restoration ecology?
A) to replace a ruined ecosystem with a more suitable ecosystem for that area
B) to speed up the restoration of a degraded ecosystem
C) to completely restore a disturbed ecosystem to its former undisturbed state
D) to prevent further degradation by protecting an area with park status
E) to manage competition between species in human-altered ecosystems
54) Which of the following is an example of bioremediation?
A) using a bulldozer to reshape the land around an abandoned strip mine to change erosion
patterns
B) dredging a river bottom to remove contaminated sediments
C) reconfiguring the channel of a river to increase the flow of water down a river
D) raising chromium-accumulating plants to extract chromium from contaminated soil
E) selectively harvesting younger trees in a forest to leave older trees for woodpecker nesting
habitat
55) To selectively remove soil toxins from regions affected by Hurricane Katrina, some residents
are growing sunflowers and other plants in their yards. Once mature, the plants are pulled and
safely stored with other contaminated wastes. This is an example of
A) biological augmentation.
B) reducing primary production.
C) lowering production efficiency.
D) bioremediation.
E) arresting nutrient cycling.
56) Corn production in many states of the Midwest is limited by nitrogen levels in the soil. Some
farmers reduce the need to apply expensive anhydrous 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
A) biological augmentation.
B) the biomass pyramid.
C) promoting leaching efficiency.
D) bioremediation.
E) trophic efficiency.