Ch. 55 Ecosystems
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?
C.tropical rain forest
Which of the following terms encompasses all of the others?
To recycle nutrients, an ecosystem must have, at a minimum, _____.
A.producers, primary consumers, secondary consumers, and
C.producers, primary consumers, and decomposers
D.producers and decomposers
Which of the following is an example of an ecosystem?
A.the intricate interactions of the various plant and animal species
on a savanna during a drought
B.the plants, animals, and decomposers that inhabit an alpine meadow
C.all of the organisms and their physical environment in a tropical rain forest
D.all of the brook trout in a 500-square-hectare river drainage system
Examine this food web for a particular terrestrial ecosystem. Which species is autotrophic?
Examine this food web for a particular terrestrial ecosystem. Which species is most likely a decomposer on this food web?
Examine this food web for a particular terrestrial ecosystem. Species C is toxic to predators. Which species is most likely to benefit from being a mimic of C?
Examine this food web for a particular terrestrial ecosystem. Which pair of species could be omnivores?
A.A and D
B.B and C
C.C and D
D.C and E
If the figure above represents a marine food web, the smallest organism might be _____.
Which of the following organisms is INCORRECTLY paired with its trophic level?
A.grasshopper – primary consumer
B.zooplankton – primary producer
C.fungus – detritivore
D.cyanobacterium – primary producer
Which of the following has the greatest effect on the rate of
chemical cycling in an
A.the rate of decomposition in the ecosystem
B.the ecosystem's rate of primary production
C.the production efficiency of the ecosystem's consumers
D.the trophic efficiency of the ecosystem
Matter is gained or lost in ecosystems. How does this occur?
A.Heterotrophs convert heat to energy.
B.Photosynthetic organisms convert solar energy to sugars.
C.Chemoautotrophic organisms can convert matter to energy.
D.Matter can be moved from one ecosystem to another.
The relationship between biomass and primary productivity is that _____.
A.biomass is the rate of primary productivity
B.biomass is the inverse of primary productivity
C.biomass is the natural log of primary productivity
D.primary productivity is the inverse of biomass
E.primary productivity is the rate at which biomass is produced
Which category in the figure above makes available the highest productivity per square meter?
B.algal beds and reefs
D.tropical wet forest
Considering its total area covered, which ecosystem type represented in the figure above has a very low level of economic impact on Earth's ecosystem?
A.rock, sand, and ice
B.tropical wet forest
C.tropical seasonal forest
D.ocean neritic zone
Why is terrestrial productivity higher in equatorial climates?
A.Productivity increases with temperature.
B.Productivity increases with available sunlight.
C.Productivity increases with water availability.
D.The answer is most likely a combination of the other responses.
After looking at the experiment in the figure above, what can be said about productivity in marine ecosystems?
A.Iron can be a limiting nutrient in
B.Productivity increases when chlorophyll a is added.
C.Nothing can be said based on this information.
D.Marine organisms break down iron for energy and thus for productivity.
During a year, plants never use 100% of the incoming solar radiation
for photosynthesis. What is a reasonable explanation for this?
I) Plants cannot photosynthesize as well during winter (in cold winter climates).
II) Plants cannot photosynthesize as well on cloudy days.
III) The pigments that drive photosynthesis respond to only a fraction of the wavelengths that are available.
D.I, II, and III
Suppose you are studying the nitrogen cycling in a pond ecosystem over the course of a month. While you are collecting data, a flock of one hundred Canada geese lands and spends the night during a fall migration. What could you do to eliminate error in your study as a result of this event?
A.Find out how much nitrogen is eliminated by a Canada goose over
about a twelve-hour period, multiply this number by 100, and subtract
that amount from the total nitrogen in the ecosystem.
B.Put a net over the pond so that no more migrating flocks can land on the pond and alter the nitrogen balance of the pond.
C.Find out how much nitrogen is consumed in plant material by a Canada goose over about a twelve-hour period, multiply this number by 100, and add that amount to the total nitrogen in the ecosystem.
D.Find out how much nitrogen is consumed and eliminated by a Canada goose over about a twelve-hour period and multiply this number by 100; enter this +/- value into the nitrogen budget of the ecosystem.
As big as it is, the ocean is nutrient-limited. If you wanted to investigate this phenomenon, one reasonable approach would be to _____.
A.observe Antarctic Ocean productivity from year to year to see if
B.compare nutrient concentrations between the photic zone and the benthic zone in various marine locations
C.contrast nutrient uptake by autotrophs in marine locations that are different temperatures
D.experimentally enrich some areas of the ocean and compare their productivity to that of untreated areas
Which of the following is a true statement regarding mineral nutrients in soils and their implication for primary productivity?
A.Phosphorous is sometimes unavailable to producers due to
B.Alkaline soils are more productive than acidic soils.
C.Adding a nonlimiting nutrient will stimulate primary productivity.
D.Globally, phosphorous availability is most limiting to primary productivity.
Why is net primary production (NPP) a more useful measurement to an ecosystem ecologist than gross primary production (GPP)?
A.NPP shows the rate at which the standing crop is utilized by
B.NPP represents the stored chemical energy that is available to consumers in the ecosystem.
C.NPP can be expressed in energy/unit of area/unit of time.
D.NPP can be expressed in terms of carbon fixed by photosynthesis for an entire ecosystem.
How is net ecosystem production (NEP) typically estimated in ecosystems?
A.the rate of decomposition by detritivores
B.the amount of heat energy released by the ecosystem
C.the annual total of incoming solar radiation per unit of area
D.the net flux of carbon dioxide or oxygen in or out of an ecosystem
How is it that satellites can detect differences in primary productivity on Earth?
A.Satellites compare the wavelengths of light captured and reflected
by photoautotrophs in different ecosystems.
B.Satellite instruments can detect reflectance patterns of the photosynthetic organisms of different ecosystems.
C.Sensitive satellite instruments can measure the amount of NADPH (nicotinamide adenine dinucleotide phosphate) produced in the summative light reactions of different ecosystems.
D.Satellites detect differences by measuring the amount of water vapor emitted by transpiring producers.
Acid precipitation lowered the pH of soil in a terrestrial ecosystem that supported a diverse community of plants and animals. The decrease in pH eliminated all nitrogenfixing bacteria populations in the area. Which prediction most accurately reflects the impact this will have on the community?
A.The decrease in pH actually increases the availability of soil
nutrients, so other nutrients that were less available cause an
increase in primary production and an increase in biomass at other
B.Primary producers will suffer from nitrogen deficiency and the entire community will experience a decrease in carrying capacity.
C.Plants can obtain the nitrogen necessary for growth from the atmosphere, but bacterial communities will be negatively impacted.
D.Since phosphorus can replace nitrogen as an essential nutrient, the impact will be minimal.
_____ are secondary consumers.
Approximately _____% of the energy at one trophic level is passed on to the next highest trophic level.
10,000 kcal of producer could support approximately _____ kcal of tertiary consumer.
Approximately what percentage of the energy in the caterpillar’s food
is actually used for secondary production (growth)?
Approximately what percentage of the energy in the caterpillar’s food is actually used for secondary production (growth)?
Why is a diagram of energy flow from trophic level to trophic level shaped like a pyramid?
A.Organisms at each level store most of the energy and pass little
B.There are more producers than primary consumers, and so on.
C.Organisms eventually die.
D.Most energy at each level is lost, leaving little for the next.
E.Secondary consumers are larger than primary consumers, and so on.
h one of the following correctly ranks these organisms in order from lowest to highest percent in production efficiency?
A.mammals, insects, fish
B.insects, fish, mammals
C.mammals, fish, insects
D.fish, insects, mammals
Owls eat rats, mice, shrews, and small birds. Assume that, over a period of time, an owl consumes 5000 J of animal material. The owl loses 2300 J in feces and owl pellets and uses 2500 J for cellular respiration. What is the production efficiency of this owl?
After looking at the figure above, what can be said about productivity in this ecosystem?
A.Productivity increases with each trophic level.
B.Between 80% and 90% of the energy is lost between most trophic levels.
C.Nothing can be said based on this information.
D.Between 10% and 20% of the energy is lost between most trophic levels.
How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level predators?
A.Predators have relatively large population sizes.
B.Predators are more disease-prone than animals at lower trophic levels.
C.Top-level predators are destined to have small populations that are sparsely distributed.
D.Top-level predators are more likely to be stricken with parasites.
Why does a vegetarian leave a smaller ecological footprint than an omnivore?
A.Eating meat is an inefficient way of acquiring photosynthetic
B.Fewer animals are slaughtered for human consumption.
C.There is an excess of plant biomass in all terrestrial ecosystems.
D.Vegetarians need to ingest less chemical energy than omnivores.
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.at each step, energy is lost from the system
B.top carnivores and secondary consumers have a more general diet than primary producers
C.biomagnification of toxic materials limits the secondary consumers and top carnivores
D.secondary consumers and top carnivores require less energy than producers
Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?
A.Decomposers compete with higher-order consumers for nutrients and
B.Nutrient cycling rates tend to be limited by decomposition.
C.Energy transfer between trophic levels is usually less than 20 percent efficient.
D.Many primary and higher-order consumers are opportunistic feeders.
Which trophic level is most vulnerable to extinction?
A.tertiary consumer level
C.secondary consumer level
D.primary consumer level
Consider the food chain of grass → grasshopper → mouse → snake → hawk. About how much of the chemical energy fixed by photosynthesis of the grass (100 percent) is available to the hawk?
An ecosystem is unlikely to be limited by the supply of _____ because it is obtained from the air.
Biogeochemical cycles are crucial to ecosystem function because _____.
A.they keep the planet warm enough for living things to
B.nutrients and other life-sustaining molecules are in limited supply and must be continually recycled
C.energy flows through ecosystems in one direction only and is eventually dissipated as heat
D.they remove poisons and keep them locked up in "sinks"
E.they prevent catastrophic extinctions
Based on the experiment in the figure above, which of the following
are plausible reasons for the result?
I) No nutrients evaporate now that vegetation is absent.
II) Nutrients dissolve in the water running through the watershed.
III) Nutrients are attached to small particles of sand or clay that leave the watershed.
IV) Plant roots that held soil particles in place are no longer there.
A.only I, II, and IV
B.only II, III, and IV
C.only II and IV
D.only I and III
Consider the global water cycle depicted in the figure above. Which one of the reserves contains the smallest percentage of global water?
B.polar ice caps
D.rivers and lakes
Consider the global nitrogen cycle depicted in the figure above. What is the limiting portion of the cycle for plants?
A.nitrogen lost to the atmosphere
B.industrial nitrogen fixation
C.internal nitrogen cycling in the oceans
D.nitrogen fixation by bacteria
Consider the global nitrogen cycle depicted in the figure above. How are humans altering this cycle?
A.industrial nitrogen fixation
B.nitrogen lost to the atmosphere
C.reduction of nitrogen available to terrestrial ecosystems
D.reduction of nitrogen fixation by bacteria
Which of the following locations are major reservoirs for carbon for
the carbon cycle?
II) sediments and sedimentary rocks
III) fossilized plant and animal remains (coal, oil, and natural gas)
IV) plant and animal biomass
A.only I and III
B.only II and IV
C.I, II, III, and IV
D.only II, III, and IV
Which of the following statements is correct about biogeochemical cycling?
A.The phosphorus cycle involves the recycling of atmospheric
B.The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic components of the ecosystem.
C.The carbon cycle has maintained a constant atmospheric concentration of carbon dioxide for the past million years.
D.The phosphorus cycle involves the weathering of rocks.
The Hubbard Brook watershed deforestation experiment revealed that
I) deforestation increased water runoff
II) nitrate concentration in waters draining the deforested area became dangerously high
III) calcium levels remained high in the soil of deforested areas
D.only I and II
Why do logged tropical rain forest soils typically have nutrient-poor soils?
A.Most of the nutrients in the ecosystem are removed in the
B.Logging results in soil temperatures that are lethal to nitrogen-fixing bacteria.
C.The cation exchange capacity of the soil is reversed as a result of logging.
D.Tropical bedrock contains little phosphorous.
The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as _____.
Which of the following would be considered an example of bioremediation?
A.adding seeds of a chromium-accumulating plant to soil contaminated
B.adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen availability
C.dredging a river bottom to remove contaminated sediments
D.using a bulldozer to regrade a strip mine
The goal of restoration ecology is to _____.
A.prevent further degradation by protecting an area with park
B.return degraded ecosystems to a more natural state
C.replace a ruined ecosystem with a more suitable ecosystem for that area
D.manage competition between species in human-altered ecosystems