1) How do the Taylor Glacier bacteria produce their energy?
A)
photosynthesis
B) heterotrophism
C) chemoautotrophism
D) thermophobism
E) chemosynthesis
Answer: C
2) In ecosystems, why is the term cycling used to describe material
transfer, whereas the term flow is used for energy exchange?
A)
Materials are repeatedly used, but energy flows through and out of
ecosystems.
B) Both material and energy are recycled and are
then transferred to other ecosystems as in a flow.
C) Materials
are cycled into ecosystems from other ecosystems, but energy
constantly flows within the ecosystem.
D) Both material and
energy flow in a never-ending stream within an ecosystem.
E)
None of the choices is correct.
Answer: A
3) Which statement most accurately describes how matter and energy
are used in ecosystems?
A) Matter is cycled through ecosystems;
energy is not.
B) Energy is cycled through ecosystems; matter is
not.
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.
Answer: A
4) The law of conservation of matter 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)
Matter can be moved in/out of an ecosystem from/to another ecosystem.
C) Photosynthetic organisms convert solar energy to sugars.
D) Detrivores convert matter to energy.
E) Heterotrophs
convert heat to energy.
Answer: B
5) 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.
D) use chemical energy to synthesize organic compounds.
E)
convert light energy into matter.
Answer: C
6) A cow's herbivorous diet indicates that it is a(n)
A)
primary consumer.
B) secondary consumer.
C) decomposer.
D) autotroph.
E) producer.
Answer: A
7) 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.
Answer: B
8) Which of the following terms encompasses all of the others?
A) heterotrophs
B) herbivores
C) carnivores
D)
primary consumers
E) secondary consumers
Answer: A
9) Many homeowners mow their lawns during the summer and collect the
clippings, which are then hauled to the local landfill. Which of the
following actions would most benefit the suburban ecosystem?
A)
Allow sheep to graze the lawn and then collect the sheep's feces to be
delivered to the landfill.
B) Collect the lawn clippings and
burn them.
C) Collect the lawn clippings and add them to a
compost pile, don't collect the clippings and let them decompose into
the lawn, or apply composted clippings to the lawn.
D) Collect
the clippings and wash them into the nearest storm sewer that feeds
into the local lake.
E) Dig up the lawn and cover the yard with asphalt.
Answer: C
10) Which of the following is an example of an ecosystem?
A)
All of the brook trout in a 500 hectare² 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)
Interactions between all of the organisms and their physical
environment in a tropical rain forest.
Answer: E
11) 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) benthic ocean
D)
grassland
E) desert
Answer: C
12) Which of the following is true of detrivores?
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, while others are heterotrophic.
Answer: C
13) 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 organic remains of organisms, feces, and so
on.
D) return energy lost to the ecosystem by other organisms.
Answer: B
14) 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
are 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.
Answer: B
15) What percentage of solar radiation striking a plant is converted
into chemical energy?
A) 1%
B) 10%
C) 25%
D)
50%
E) 100%
Answer: A
16) 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
Answer: C
17) 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
Answer: D
18) Which of these ecosystems has the highest net primary
productivity per square meter?
A) savanna
B) open ocean
C) boreal forest
D) tropical rain forest
E)
temperate forest
Answer: D
19) Which data is most useful to measure primary productivity in a
terrestrial ecosystem?
A) temperature readings
B)
potential evapotranspiration
C) intensity of solar radiation
D) annual precipitation
E) amount of carbon fixed
Answer: D
20) 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.
Answer: D
21) 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.
Answer: B
22) 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.
Answer: C
23) 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 is 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.
Answer: C
24) 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 detrivores
E) the annual total of incoming
solar radiation per unit of area
Answer: C
25) 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
Answer: A
26) Aquatic ecosystems are least likely to be limited by which of the
following nutrients?
A) nitrogen
B) carbon
C)
phosphorus
D) iron
E) zinc
Answer: B
27) What is the primary limiting factor for aquatic productivity?
A) pressure
B) lack of nutrients
C) light
availability
D) herbivores
E) competition
Answer: B
28) 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) grassland
because of the small standing crop biomass that results from
consumption by herbivores and rapid decomposition
C) tropical
rain forest because of the massive standing crop biomass and 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
Answer: B
29) 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.
Answer: D
30) 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
Answer: A
31) 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 runoff
D) accidental introduction of a
prolific culture of algae
E) iron dust blowing into the lake
Answer: C
32) The amount of chemical energy in consumers' food that is
converted to their 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
Answer: E
33) 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
Answer: C
34) 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.
Answer: A
35) 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.
Answer: B
36) 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 2,500 J for cellular
respiration. What is the primary efficiency of this owl?
A)
0.02%
B) 1%
C) 4%
D) 10%
E) 40%
Answer: C
37) 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.
Answer: E
38) For most terrestrial ecosystems, pyramids of numbers, biomass,
and energy are essentially the samethey 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 as a
result of keeping the organisms alive.
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.
Answer: B
39) 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 tropic levels is in
almost all cases less than 20% efficient.
Answer: E
40) 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
Answer: D
41) Secondary consumers that can eat only primary consumers receive
what percent of the energy fixed by primary producers in a typical
field ecosystem?
A) 0.1%
B) 1%
C) 10%
D) 20%
E) 80%
Answer: B
42) 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.
Answer: D
43) 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%
Answer: A
44) 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.
Answer: E
45) Nitrogen is available to plants only in the form of
A) N2
in the atmosphere.
B) nitrite ions in the soil.
C) uric
acid from animal excretions.
D) amino acids from decomposing
plant and animal proteins.
E) nitrate ions in the soil.
Answer: E
46) Which of the following locations is the reservoir for nitrogen in
the 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
Answer: A
47) Which of the following locations is the reservoir for carbon for
the carbon cycle?
A) atmosphere
B) sediments and
sedimentary rocks
C) fossilized plant and animal remains (coal,
oil, and natural gas)
D) plant and animal biomass
E) all
of the above
Answer: E
48) In the nitrogen cycle, the bacteria that replenish the atmosphere
with N2 are
A) Rhizobium bacteria.
B) nitrifying bacteria.
C) denitrifying bacteria.
D) methanogenic protozoans.
E) nitrogen-fixing bacteria.
Answer: C
49) How does phosphorus normally enter ecosystems?
A) cellular
respiration
B) photosynthesis
C) rock weathering
D)
vulcanism
E) atmospheric phosphorous gas
Answer: C
50) Which of the following is an example of a local biogeochemical
cycle?
A) O₂ released by oak trees in a forest
B) CO₂
absorbed by phytoplankton in the open ocean
C) excess NO₃-
converted to N₂ by denitrifying soil bacteria
D) phosphorous
being absorbed from the soil by a corn plant
E) organic carbon
remains of a leaf being converted to CO₂ by a fungus
Answer: D
51) Which of the following statements is correct about biogeochemical
cycling?
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.
Answer: B
52) Which of the following properly links the nutrient to its
reservoir?
A) nitrogenionic nitrogen in the soil
B)
wateratmospheric water vapor
C) carbondissolved CO₂ in aquatic
ecosystems
D) phosphoroussedimentary rocks
E) All of the
options are correct.
Answer: D
53) In terms of nutrient cycling, why does timber harvesting in a
temperate forest cause less ecological devastation than timber
harvesting in tropical rain forests?
A) Trees are generally less
numerous in temperate forests, so fewer nutrients will be removed from
the temperate forest ecosystem during a harvest.
B) Temperate
forest tree species require fewer nutrients to survive than their
tropical counterpart species, so a harvest removes fewer nutrients
from the temperate ecosystem.
C) The warmer temperatures in the
tropics influence rain forest species to assimilate nutrients more
slowly, so tropical nutrient absorption is much slower than in
temperate forests.
D) There are far fewer decomposers in
tropical rain forests, so turning organic matter into usable nutrients
is a slower process than in temperate forest ecosystems.
E)
Typical harvests remove up to 75% of the nutrients in the woody trunks
of tropical rain forest trees, leaving nutrient-impoverished soils behind.
Answer: E
54) Why do logged tropical rain forest soils typically have
nutrient-poor soils?
A) Tropical bedrock contains little
phosphorous.
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) The cation
exchange capacity of the soil is reversed as a result of logging.
E) Nutrients evaporate easily into the atmosphere in the
post-logged forest.
Answer: C
55) What is the first step in ecosystem restoration?
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
Answer: A
56) 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
Answer: B
57) 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.
Answer: C
58) In a typical grassland community, which of the following has the
smallest biomass?
A) hawk
B) snake
C) shrew
D)
grasshopper
E) grass
Answer: A
59) In a typical grassland community, which of the following is the
primary consumer?
A) hawk
B) snake
C) shrew
D)
grasshopper
E) grass
Answer: D
60) When levels of CO₂ are experimentally increased in a typical
grassland community, C₃ plants generally respond with a greater
increase in productivity than C₄ plants. This is because
A) C₃
plants are more efficient in their use of CO₂.
B) C₃ plants are
able to obtain the same amount of CO₂ by keeping their stomata open
for shorter periods of time.
C) C₄ plants don't use CO₂ as their
source of carbon.
D) C₃ plants are more limited by CO₂
availability because they lack mechanisms to prevent transpirational
water loss.
E) C₃ plants have special adaptations for CO₂
uptake, such as larger stomata.
Answer: D
Food web for a particular terrestrial ecosystem (arrows represent
energy flow and letters represent species)
61) Examine
this food web for a particular terrestrial ecosystem. Which species is
autotrophic?
A) A
B) B
C) C
D) D
E) E
Answer: A
Food web for a particular terrestrial ecosystem (arrows represent
energy flow and letters represent species)
62) Examine
this food web for a particular terrestrial ecosystem. Which species is
most likely a decomposer on this food web?
A) A
B) B
C) C
D) D
E) E
Answer: E
Food web for a particular terrestrial ecosystem (arrows represent
energy flow and letters represent species)
63) 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?
A) A
B) B
C) C
D) D
E) E
Answer: B
Food web for a particular terrestrial ecosystem (arrows represent
energy flow and letters represent species)
64) Examine
this food web for a particular terrestrial ecosystem. Which pair of
species could be omnivores?
A) A and B
B) A and D
C)
B and C
D) C and D
E) C and E
Answer: E
Diagram of a food web (arrows represent energy flow and letters
represent species)
65) If the figure above represents a
terrestrial food web, the combined biomass of C + D would probably be
A) greater than the biomass of A.
B) less than the biomass
of H.
C) greater than the biomass of B.
D) less than the
biomass of A + B.
E) less than the biomass of E.
Answer: D
Diagram of a food web (arrows represent energy flow and letters
represent species)
66) If the figure above represents a
marine food web, the smallest organism might be
A) A.
B)
F.
C) C.
D) I.
E) E.
Answer: A
67) On the diagram of the nitrogen cycle, which number represents
nitrite (NO₂)?
A) 1
B) 2
C) 3
D) 4
Answer: C
68) On the diagram of the nitrogen cycle, which number represents
ammonia (NH₄+)?
A) 1
B) 2
C) 3
D) 4
Answer: D
69) On the diagram of the nitrogen cycle, which number represents
nitrogen-fixing bacteria?
A) 5
B) 6
C) 7
Answer: A
70) On the diagram of the nitrogen cycle, which number represents
nitrifying bacteria?
A) 5
B) 6
C) 7
Answer: B
71) 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
100 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 consumed in plant
material by a Canada goose over about a 12-hour period, multiply this
number by 100, and add that amount to the total nitrogen in the
ecosystem.
B) Find out how much nitrogen is eliminated by a
Canada goose over about a 12-hour period, multiply this number by 100,
and subtract that amount from the total nitrogen in the ecosystem.
C) Find out how much nitrogen is consumed and eliminated by a
Canada goose over about a 12-hour period and multiply this number by
100; enter this +/- value into the nitrogen budget of the ecosystem.
D) Do nothing. The Canada geese visitation to the lake would
have negligible impact on the nitrogen budget of the pond.
E)
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.
Answer: C
72) As big as it is, the ocean is nutrient-limited. If you wanted to
investigate this, one reasonable approach would be to
A) follow
whale migrations in order to determine where most nutrients are
located.
B) observe Antarctic Ocean productivity from year to
year to see if it changes.
C) experimentally enrich some areas
of the ocean and compare their productivity to that of untreated
areas.
D) compare nutrient concentrations between the photic
zone and the benthic zone in various marine locations.
E)
contrast nutrient uptake by autotrophs in marine locations that are
different temperatures.
Answer: C
73) A porcupine eats 3,000 J of plant material. Of this, 2,100 J is
indigestible and is eliminated as feces, 800 J are used in cellular
respiration, and 100 J are used for growth and reproduction. What is
the approximate production efficiency of this animal?
A) 0.03%
B) 3%
C) 10%
D) 27%
E) 33%
Answer: B
74) Which of the following organisms is incorrectly paired with its
trophic level?
A) cyanobacteriumprimary producer
B)
grasshopperprimary consumer
C) zooplanktonprimary producer
D) eagletertiary consumer
E) fungusdetritivore
Answer: C
75) Which of these ecosystems has the lowest net primary production
per square meter?
A) a salt marsh
B) an open ocean
C) a coral reef
D) a grassland
E) a tropical rain forest
Answer: B
76) The discipline that applies ecological principles to returning
degraded ecosystems to a more natural state is known as
A)
population viability analysis.
B) landscape ecology.
C)
conservation ecology.
D) restoration ecology.
E) resource conservation.
Answer: D
77) Nitrifying bacteria participate in the nitrogen cycle mainly by
A) converting nitrogen gas to ammonia.
B) releasing
ammonium from organic compounds, thus returning it to the
soil.
C) converting ammonia to nitrogen gas, which returns to the
atmosphere.
D) converting ammonium to nitrate, which plants
absorb.
E) incorporating nitrogen into amino acids and organic compounds.
Answer: D
78) Which of the following has the greatest effect on the rate of
chemical cycling in an
ecosystem?
A) the ecosystem's rate
of primary production
B) the production efficiency of the
ecosystem's consumers
C) the rate of decomposition in the
ecosystem
D) the trophic efficiency of the ecosystem
E)
the location of the nutrient reservoirs in the ecosystem
Answer: C
79) The Hubbard Brook watershed deforestation experiment yielded all
of the following results except:
A) Most minerals were recycled
within a forest ecosystem.
B) The flow of minerals out of a
natural watershed was offset by minerals flowing in.
C)
Deforestation increased water runoff.
D) The nitrate
concentration in waters draining the deforested area became
dangerously high.
E) Calcium levels remained high in the soil of
deforested areas.
Answer: E
80) Which of the following would be considered an example of
bioremediation?
A) adding nitrogen-fixing microorganisms to a
degraded ecosystem to increase nitrogen availability
B) using a
bulldozer to regrade a strip mine
C) dredging a river bottom to
remove contaminated sediments
D) reconfiguring the channel of a
river
E) adding seeds of a chromium-accumulating plant to soil
contaminated by chromium
Answer: A
81) If you applied a fungicide to a cornfield, what would you expect
to happen to the rate of decomposition and net ecosystem production
(NEP)?
A) Both decomposition rate and NEP would decrease.
B) Both decomposition rate and NEP would increase.
C)
Neither would change.
D) Decomposition rate would increase and
NEP would decrease.
E) Decomposition rate would decrease and NEP
would increase.
Answer: E