Ecology
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1 A student is planning a field investigation to compare the numbers of insects and spiders in two
different one-square meter areas that she has marked. One area includes a rotting tree in the woods
behind her school. The other is in the parking lot of her school. Which would be the MOST accurate
prediction to make before the investigation begins?
A The area in the parking lot will contain more spiders than insects.
B The area in the woods will contain equal numbers of spiders and insects.
C Both areas will contain more centipedes and millipedes than insects and spiders.
D The area in the woods will contain more insects and spiders than the area in the parking lot.
2 Which of the following relationships exists between the frog and the mayfly?
F commensalism
G competition
H mutualism
J predation
3 Which output from a bear can be used by salmonberry plants in a forest habitat?
A Carbon dioxide from bears is used for photosynthesis in plants.
B Oxygen from bears is used for photosynthesis in plants.
C Glucose from bears is used for respiration in plants.
D Water from bears is used for respiration in plants.
4 Adding habitat is a solution to the problem of decreased butterfly populations in prairie ecosystems.
What could be an unintended consequence of adding habitat for butterflies?
F Beneficial nutrients could be removed from the ecosystem.
G The air temperature could increase in the ecosystem.
H Materials new to the ecosystem could be introduced.
J The amount of light in the ecosystem could increase.
5 Muskrats are omnivores that live in burrows on the pond banks. Which of the following would most
likely lead to an increase in the size of the muskrat population over time?
A increased seed production by cattails
B increased outbreaks of disease in muskrats
C increased numbers of predators on muskrats
D increased amounts of competition from pickerel
6 Which of the following organisms is correctly matched to its role in the pond ecosystem?
F soil fungi—decomposer
H water lily—decomposer
G zooplankton—producer
J water snake—primary consumer
7 A correlation exists between the number of cases of moose brainworm disease and the density of the
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deer population.
Which of the following statements gives the best explanation for this relationship?
A High deer population density causes individual deer to reproduce more.
B High deer population density speeds up the life cycle of the roundworm.
C High deer population density attracts more moose to an area where they will become infected.
D High deer population density results in more larvae-infected waste for snails to encounter in an area.
Which of the following lemurs would be classified as a secondary consumer?
F a mouse lemur eating insects
H a ring-tailed lemur eating fruits
G a Verreaux’s sifaka eating leaves
J a red-bellied lemur eating flowers
The moose belongs to which trophic level in an ecosystem?
A producer
C scavenger
B consumer
D decomposer
Some species of penguins, such as chinstrap penguins, depend on open water for their survival.
Other species of penguins, such as Adélie penguins, depend on ice. Over the last 20 years, the
population size of chinstrap penguins has increased, and the population size of Adélie penguins has
decreased. Which of the following most likely caused these changes in population size?
F an increase in landmass and shorelines
G an increase in global air and water temperatures
H a decrease in the number of leopard seal predators
J a decrease in the length of time before chicks take to sea
A simple food web is shown below.
Which of the following is most likely to lead to the greatest decrease in the deer mouse population?
A an increase in the owl population
B an increase in the grass population
C an increase in the pine tree population
D an increase in the cottontail population
12 A company that produces pesticides conducts an experiment to test the effectiveness of their newest
product. The scientist involved in the development of the pesticide is the one who will interpret the
results. Why is this a problem?
F The pesticide could be made better during the process.
G The results could be shared with a competing company.
H The scientist will not know how to make accurate observations.
J The scientist may misinterpret the results because he knows what should happen.
13 Geothermal energy can be converted from hot water or steam from deep within Earth’s surface and
transformed into electricity. One disadvantage of geothermal energy is that
A it is a nonrenewable resource.
B habitats can be destroyed when drilling.
C it releases hazardous waste into the atmosphere.
D emitted toxins can gather in animals’ bodies over time.
14 One kind of bacteria lives, secretes enzymes into, and consumes dead organic matter in areas without
oxygen. These bacteria can be classified as
F parasites.
H eukaryotes.
G autotrophs.
J decomposers.
15 Which organism in the aquatic food web below gets energy directly from the Sun?
A krill
B baleen whale
C phytoplankton
D both krill and the baleen whale
a single plant species is removed from a food web, then most likely —
an animal species will fill the unoccupied niche
other plants will produce enough food for herbivores
dependent herbivores will have to find new food sources
carnivores will be unaffected by the loss
17 Which order of diagrams would show primary succession in an area that had never before been
occupied by living organisms?
A C, A, B, D
C D, B, C, A
B B, A, C, D
D A, C, B, D
16 If
F
G
H
J
18 How would the development of hybrid cars minimize the effects of human population growth on the
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environment?
F by increasing noise pollution
G by increasing smog production
H by decreasing dependence on fossil fuels
J by decreasing the number of people traveling on highways
A horse eats an apple from a tree. Which statement best explains this relationship?
A Both the horse and the tree are heterotrophs.
B The horse, a heterotroph, is consuming food from an autotroph.
C Both the horse and the tree are neither autotrophs nor heterotrophs.
D The horse, an autotroph, is consuming food from another autotroph.
Which best describes the interaction between autotrophs and heterotrophs?
F One competes with the other for access to sunlight and soil.
G One decomposes the other to release nutrients back into the soil.
H One helps produce the other in a mutually beneficial relationship.
J One consumes the other to use energy that originally came from the Sun.
One problem with imposing heavy fines on businesses that do not meet legal or environmental
standards with their waste emissions, is that such actions may result in
A political opposition from the business’ supporters.
B the businesses increasing their need for fossil fuels.
C the businesses increasing their number of employees.
D prices of the services offered by the businesses going down.
What is a main difference between primary succession and secondary succession?
F Primary succession happens slowly, and secondary succession happens
rapidly.
G Small plants grow first during primary succession, while large trees grow first
during secondary succession.
H Primary succession occurs after a natural disaster, and secondary succession
occurs before a natural disaster.
J Primary succession is the colonization of new sites, and secondary succession
is colonization of previously inhabited sites.
A certain light-producing microbe finds shelter and food in the skin of a fish. This relationship would
be considered mutualism if the light from the microbe
A helps the fish find suitable mates.
B causes harmful mutations in the fish.
C makes the fish more easily preyed upon.
D makes no difference in the life of the fish.
A land developer wants to control a population of hawks. He decides to solve the problem by
clearing out the land’s fields. How will this action most likely control the population?
F The population of hawks will increase due to decreased competition.
G The hawks will experience more crowding and the population will decline.
H There will be fewer predators of the hawks, so their population will increase.
J The food supply of the hawks will decrease, causing the population of hawks
to decrease.
A plan to convert and burn unsold food as biological fuel can be environmentally beneficial because
it
A restores wetlands.
C reduces air pollution.
B limits landfill use.
D decreases biodiversity.
26 In Calhoun County, Arkansas, a local timber company is now required to grow pine trees for 45
years before harvesting instead of the normal 20 years. This would increase biodiversity in Calhoun
County through the
F reduction of pollution.
H elimination of extinction.
G preservation of habitats.
J simplification of food webs.
27 Which best describes the interaction between autotrophs and heterotrophs?
A One competes with the other for access to sunlight and soil.
B One decomposes the other to release nutrients back into the soil.
C One helps produce the other in a mutually beneficial relationship.
D One consumes the other to use energy that originally came from the Sun.
28 Which presents the correct order of biomes from least biodiversity to most biodiversity?
F tundra, taiga, temperate grassland, rainforest
G taiga, tundra, temperate grassland, rainforest
H tundra, taiga, rainforest, temperate grassland
J taiga, tundra, rainforest, temperate grassland
29 The figure below shows the number of plants and animals necessary to support the life of one
high-level consumer in a temperate grassland biome.
The figure represents the flow of energy through
A different trophic levels in most ecosystems
B soil, plants, and animals during the nitrogen cycle
C different organisms within a single level of most food webs
D the atmosphere, land, and bodies of water during the water cycle
30 A farmer stops cultivating a large tract of farmland and abandons it. The natural changes taking place
soon afterwards, such as the growth of wild grasses and weeds, can be considered secondary
succession and not primary succession because
F a new ecosystem develops
G there is already soil present
H the land is not controlled by humans
J wild grasses and weeds make soil from rocks
31 Scientists who research ways to make more effective fertilizer are applying knowledge from what
pure-science concept?
A nitrogen cycle
C natural selection
B trait inheritance
D ecological competition
32 Which level of the food chain has the greatest amount of biomass?
F Hawk
G Bird
H Grasshopper
J Grass
33 Increased reliance on which energy source would likely have the most negative effects on global
climate change?
A coal
C nuclear
B wind
D hydroelectric
34 The diagram below shows a biogeochemical cycle.
Which cycle is shown?
F water
G carbon
H nitrogen
J phosphate
35 The graph below compares and contrasts the annual rainfall and temperature of several biomes.
Which biome is represented in section 4 of the graph?
A taiga
B desert
C rainforest
D temperate forest
36 Which is an example of parasitism?
F a harmless frog looking identical to a poisonous one
G a vampire bat sucking blood from the ankle of a cow
H a bacterium breaking down wastes in a human intestine
J a pilot fish cleaning food particles from the gill slits of a shark
37 Which is the most likely order of plant life succession around a volcano that erupted and destroyed
most life forms?
A
B
C
D
38 Which biome would most likely contain the largest number of hibernating animals?
F marine
H temperate forest
G savanna
J tropical rain forest
39 The Egyptian Plover bird is allowed to fly into the mouth of a crocodile and eat food scraps found
there. Which term best describes this relationship?
C mutualism
D commensalism
40 A simplified food web is shown below.
Suppose the bird population declines due to a
shortage of nesting sites. Which organism
would be most negatively affected by a
decline in the bird population?
F spider
H grass
G snake
J toad
A predation
B parasitism
41 Which disturbance would set the stage for primary succession?
A A farmer’s field is flooded.
B A rainforest is clear cut for timber.
C A volcano covers the ground with lava.
D A fire burns through a temperate forest.
42 Manufacturers in the United States have eliminated chlorofluorocarbons from common household
aerosol products. This has reduced their contribution to which environmental problem?
F acid rain
H global climate change
G desertification
J atmospheric ozone depletion
43 A team of ecologists observed feeding patterns of several populations in the desert. The energy
pyramid shown below depicts the feeding patterns the ecologists observed.
Which of the following best explains the difference in the amount of available energy in the trophic
levels of the desert ecosystem?
A There is less energy available in the producers because their tissues are less
dense than those at higher trophic levels.
B There is more energy available in the second trophic level because less energy
is needed for hunting compared to the higher trophic levels.
C There is more available energy in the birds of prey because they have greater
muscle mass for storing energy than organisms in lower trophic levels have.
D There is less available energy in the fourth trophic level because of the loss of
energy through metabolism in each of the lower trophic levels.
44 A marine food web is shown below
Which of the following organisms is a consumer in this food web?
F Seaweed
H Clam Worm
G Sea Grass
J Phytoplankton
45 A marine food web is shown below
Which of the following organisms is found in the trophic le vel with the highest biomass that sustains
the ecosystem represented by this food web?
A Amphipod
C Redfish
B Heron
D Seaweed
46 A marine food web is shown below
Which of the following is a long-term effect on the removal of the redf ish from the ecosystem
represented by this food web?
F The osprey population will increase.
G The amphipod population will increase.
H The clam worm population will increase.
J The phytoplankton population will increase.
47 The number of pythons found throughout Everglades National Park has increased in recent years.
These huge snakes are not native to Florida and are believed to have been released into the wild by
pet owners. Wildlife biologists have initiated attempts to capture and remove these pythons. Which
statement best explains the biologists’ reason for removing these pythons from the Everglades?
A The pythons could upset the territorial boundaries of native organisms.
B The pythons could adapt to overcome diseases common to native snake
C The pythons could prey on native organisms and cause native populations to decline
D The pythons could begin to interbreed with native snakes and produce a more successful species.
48 Salt water is an abundant resource but unusable for irrigation and drinking. As demands on
freshwater sources increase, the use of desalination processes to remove salt from ocean water is
increasing. A concern of desalinating water is the large amounts of recovered salts that are returned
to the ocean. Which of the following describes the most likely impact of desalination on the
surrounding ocean environment?
F Methane gas would pollute the ocean environment as shoreline organisms
begin to die and decay.
G Alteration in ocean salt levels would cause loss of species and unbalanced
populations in marine food webs.
H Nonrenewable resources in the ocean environment would become depleted
and upset the ecosystem’s balance.
J Increased levels of salts and minerals in the ocean would result in
overpopulation of marine bivalves due to strengthened shells.
49 Which of the following correctly traces the energy transfer through the trophic levels in the
marine food web shown below?
A Fish  sea birds  seal  penguin
B Phytoplankton  krill  fish  seal
C Seal  sea birds  fish  phytoplankton
D Zooplankton  phytoplankton  krill  squid
50 Which of the following describes how the amount of energy changes as it flows from one
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trophic level to the next in the marine food web shown below?
F Energy increases as it is transferred from penguins to seals, since seals are
more massive than penguins.
G Energy decreases as it is transferred from zooplankton to fish, since
zooplankton are producers and fish are consumers.
H When krill consume phytoplankton, about 90 percent of the phytoplankton’s
energy is transferred to the krill.
J When sea birds consume fish, about 10 percent of the fish’s energy is
transferred to the sea birds.
Many insects, such as mosquitoes and dragonflies, spend their juvenile stage as aquatic larvae before
becoming winged and airborne adults. Most years, these insects are extremely abundant in the Arctic
tundra in summer. What might account for this?
A Adult insects spend the long Arctic winter laying thousands of eggs under the ice of frozen
ponds.
B Many insects migrate long distances to take advantage of good breeding areas in the tundra.
C Pools of water which make good breeding areas are plentiful in summer as the permafrost melts.
D Summer rains in the Arctic tundra replenish breeding ponds that dried up during the winter.
A population of rodents becomes stranded on a remote island. Eventually, the population reaches the
island’s carrying capacity. At this point, the birth and death rates are
F relatively equal.
H density dependent.
G crashing.
J density independent.
If a snake species were introduced to an ecosystem where it had no natural predators, what
long---term effect do you predict the snakes would have on the population dynamics of the
ecosystem?
A They would breed with native snake species, resulting in an increase in
biodiversity in the ecosystem.
B They would compete with native snake species for resources, causing a
decline in native snake populations and possibly extinction.
C They would form mutualistic relationships with native snakes, since they
would occupy the same niche in the ecosystem.
D They would serve as a food source for predators of native snakes, causing an
increase in native snake populations.
Carbon Dioxide is important in our atmosphere because it is required for photosynthesis and traps
some heat, keeping the Earth warm. However, human produced carbon dioxide is a problem because
it
F leads to higher global temperatures.
G disrupts the natural cycling of other greenhouse gases.
H add too much carbon dioxide to the oceans.
J causes uncontrolled photosynthesis.
The choices that humans make every day affect the environment. Sometimes, our lifestyles can harm
the environment rather than protect it. Which of the following would be most helpful in protecting
the environment and achieving sustainability?
A Buying paper products made from harvested trees
B Buying fewer mass produced products
C Using natural gas as a fuel source instead of petroleum
D Using solar power to generate electricity
56 Terrestrial plants have a waxy covering produced by the dermal tissues called the cuticle. If this
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waxy covering was overproduced so that the stomata became clogged, what would happen to the
plant?
F Glucose produced during photosynthesis would be prevented from reaching the rest of the plant,
and energy production by cellular respiration would stop.
G Sunlight would not be able to reach the plant's ground tissue cells through the thick dermal
tissue, and the plant's ability to perform photosynthesis would be damaged.
H The plant would not be able to absorb water and oxygen from the air, and the plant would dry
out, limiting most cell functions.
J The plant would not be able to exchange oxygen for carbon dioxide, and the plant's ability to
perform photosynthesis would be limited.
While reading a nature magazine, Sheila learned that spadefoot toads are common in areas with high
daytime temperatures, limited rainfall, and cacti as the primary vegetation. Which biome would
spadefoot toads MOST likely inhabit?
A desert
C tropical forest
B grassland
D temperate forest
Which occurrence is a major source of the gases that can produce acid rain?
F a hole in the ozone layer
H cloud-seeding by airplanes
G burning of fossil fuels
J emissions by nuclear reactors
Which of the following is an abiotic factor in an ecosystem?
A grass
C a rock
B a fox
D a worm
Which of the following practices is MOST likely to slow the buildup of CO2 in the atmosphere?
F increased use of tropical rain forest areas for agriculture
G increased use of genetically engineered plants
H decreased pesticide use in favor of biological controls
J decreased use of fossil fuels
Predators often feed on weak or sick animals in an ecosystem. The role of the predator is described as
its
A community
C niche
B habitat
D population
Which of these can help farmers counteract the negative effects on their soil?
F contour planting
H large-scale irrigation
G insect predators
J expensive fertilizers
Organisms in an ecosystem are linked together by
A geochemical pathways
C food webs
B greenhouse effects
D water cycles
Polar bears swim across large expanses of ocean while hunting for seals, their main source of
food. The bears use sea ice as resting spots during their long swims. However, the sea ice is rapidly
melting as a result of
global warming. Which statement describes what most likely will
happen if global warming continues at its present rate?
F Polar bear and seal populations will both increase.
G Polar bear populations will decrease, and seal populations will increase.
H Polar bear populations will increase, and seal populations will decrease.
J Polar bear populations will decrease, and seal populations will remain the same.
65 A forest fire destroys the majority of the trees in a state park. Which effect will this most likely have
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on secondary consumers in that ecosystem?
A The amount of available energy will increase because there will be fewer
predators in the forest.
B The amount of available energy will increase because there will be less
competition from producers.
C The amount of available energy will decrease because fewer primary
consumers will survive the lack of vegetation.
D The amount of available energy will remain constant because secondary
consumers are not reliant on primary consumers.
A new species of snake was introduced to a tropical region. Scientists then noticed a steady decline
in the presence of field mice and an increase in the number of snakes. Which of these is the most
likely explanation about why the population size of each animal changed?
F The snakes introduced to the region dominated the habitat, forcing the mice to
find another place to live.
G The mice became prey to the introduced snakes, allowing the snake
population to increase but decreasing the mice population.
H The snakes introduced to the region competed with the mice for food,
allowing the snake population to increase but decreasing the mice population.
J The people in the surrounding area set traps that killed the mice, allowing the
snakes to live without any predators and therefore to increase in number.
Which of these best describes mutualism?
A a relationship between two species where both species benefit
B a relationship between two species where neither species benefits
C a relationship between two species where one species benefits and the other is
not affected
D a relationship between two species where one species benefits and the other
species is harmed
Which abiotic factor limits the altitude at which plants can grow?
F the presence of a parasite
G the temperature of the area
H the presence of herbivorous animals
J the concentration of microbes in the soil
Bacteria living in nodules on the roots of legumes have the ability to fix atmospheric nitrogen into a
water-soluble form that plants can use. The bacteria absorb sugar from the plants’ roots. Which
describes the relationship between the bacteria and the legume plants?
A commensalism
C parasitism
B mutualism
D predation
Which situation would result in the greatest increase in the human population?
F decreased birth rate and increased death rate
G increased infant mortality and decreased death rate
H decreased death rate and increased birth rate
J increased birth rate and increased infant mortality
71 A community is studied and several interactions are observed and recorded.
Type of
Interaction
Effect on
Organism X
Effect on
Organism Y
A
Harms
Harms
B
Benefits
Harms
C
Benefits
No effects
D
Benefits
Benefits
Which type of interaction could illustrate the process of mutualism?
A interaction A
C interaction C
B interaction B
D interaction D
72 Silt and nutrients from eroding farmland flow into a lake. As a result, which will most likely
increase first?
F fish population
H algae growth
G shore vegetation
J dissolved oxygen
73 Why do ecosystems rarely contain more than a few trophic levels?
A Energy transfer efficiency is high.
C Energy amounts remain constant.
B Energy transfer efficiency is low.
D Energy cannot flow through levels.
74 This diagram shows a food web of a meadow.
Due to insecticides, the cricket population is greatly reduced. Which population is most
affected by this event?
F Mouse
H Grass
G Hawk
J Frog
75 The crab Lybia tessellata carries a pair of sea anemones on its claws. The crab uses the sea
anemone’s stinging tentacles as protection and the sea anemone obtains small food particles released
by the crab as it feeds. Which type of symbiotic relationship does this best illustrate?
A commensalism
C parasitism
B mutualism
D predation
76 In an ecosystem, which is the most likely reason for an increase in the producer population if there is
an increase in the carnivore population?
F fewer herbivores
H less food
G higher temperatures
J more oxygen
77 Which graph represents the maximum carrying capacity of a bacterial colony?
A
C
B
D
78 Which sequence shows increasing ecological levels of organization?
F organism, population, community, ecosystem
G ecosystem, population, organism, community
H community, ecosystem, population, organism
J population, organism, ecosystem, community
79 This diagram shows the flow of carbon in a terrestrial ecosystem.
Which will most likely happen if the decomposers are removed from the carbon cycle?
A The amount of carbon dioxide in the atmosphere will increase.
B The amount of carbon dioxide in the atmosphere will decrease.
C The amount of carbon dioxide used by producers will increase.
D The amount of carbon dioxide needed by consumers will decrease.
80 The diagram below represents an energy pyramid.
At each successive level from E to H, the amount of available energy
F increases, only
H remains the same
G decreases, only
J increases, then decreases
81 One possible reason for the rise in the average air temperature at Earth’s surface is that
A decomposers are being destroyed
B deforestation has increased the levels of oxygen in the atmosphere
C industrialization has increased the amount of carbon dioxide in the air
D growing crops is depleting the ozone shield
82 Which concept is best represented in the diagram shown below?
F
G
H
J
human actions are a threat to equilibrium in ecosystems.
equilibrium in ecosystems requires that humans modify ecosystems.
equilibrium in ecosystems directly affects how humans modify ecosystems.
human population growth is the primary reason for equilibrium in ecosystem
83 A major reason that humans can have such a significant impact on the ecological community is that
humans
A reproduce faster than most other species
B can modify their environment through technology
C remove large amounts of carbon dioxide from the air
D are able to increase the amount of finite resources available
84 Assume the trend in the graph above continues. Which of the following would result:
F
G
H
J
ocean levels would lower
an increase in earthquake activity
days would gradually become longer
an increase in average global temperatures
85 Cutting down a rain forest and planting agricultural crops, such as coffee plants, would result in
A a decrease in erosion
B a decrease in biodiversity
C an increase in the amount of photosynthesis
D an increase in the amount of energy recycled
86 Two closely related species of birds live in the same tree. Species A feeds on ants and termites, while
species B feeds on caterpillars. The two species coexist successfully because they
F interbreed
G compete less for food
H share the same food
J use different methods of reproduction
87 Each drawing represents different stages in the community succession within the state of Virginia.
Which of the following drawings represents the climax community in this succession pattern?
A
B
C
D
88 Which statement describes all stable ecosystems?
F herbivores provide energy for the autotrophs
G the populations of predators are dependent on the populations of the prey
H the number of autotrophs equals the number of heterotrophs
J consumers synthesize ATP from light energy
89 The biome with the greatest number of species would also have the greatest variation in —
A solar energy
C annual rainfall
B habitats
D temperatures
90 Thirty breeding pairs of rabbits were introduced onto an island with no natural predators and a good
supply of water, shrubs, and grasses. Over the next few years, the rabbit population will probably —
A . remain relatively constant due to equal birth and death rates
F die out due to inbreeding
G increase until the food supply runs low
H decrease as the number of rabbits per litter decreases
91 Which of these DECREASES as the number of fish in a small pond increases?
A Competition for food
C Number of available nesting sites
B Levels of body wastes in the pond D Number of predators
92 Why does the white-tailed deer population drop when the carrying capacity is exceeded?
F
G
H
J
Resources are too low to support the population.
Weather changes reduce the deer population.
The height of edible plants exceeds the height of the deer.
Competition by other animals is greatly reduced.
93 Which of the following is a consumer-producer relationship?
A Roadrunners eating snakes
C Toads eating grasshoppers
B Snakes eating toads
D Grasshoppers eating grass
94 Turgor is the internal cytoplasmic pressure that results from the amount of water absorbed by plant
cells. The picture shows a turgor pressure demonstration using stalks of celery in different salt
solutions. Which of these shows the celery stalks in order from the one with the most turgor pressure
to the one with the least turgor pressure?
F Q, T, S, R
G R, S, T, Q
H S, R, T, Q
J T, Q, R, S
95 Which population would be most affected if the snakes were removed from this food web?
A Grass
B Mouse
C Lizard
D Hawk
96 Low availability of which element could be a limiting factor in a plant community?
F Nitrogen
H Mercury
G Argon
J Sodium
97 Which group is most responsible for the recycling of atoms within the environment?
A Autotrophs
C Phototrophs
B Consumers
D Decomposers
98 This graph shows the average number of rabbits and coyotes in an area over time. Which conclusion
is best supported by these data?
F
G
H
J
The rabbit population obtains energy by consuming young plants.
The coyote population is influenced by the available number of rabbits.
The number of rabbits will decrease during summer months.
The number of coyotes will be greater than the number of rabbits within a
ten-year period.
99 A chemical spill was thought to be responsible for a large fish kill in a river. Which person would
most likely determine whether the fish died from being exposed to the chemicals?
A Toxicologist
C Physiologist
B Virologist
D Botanist
100 In this food pyramid, how much energy is available as the energy is passed from one trophic level to
another?
F 1%
G 10%
H 25%
J 50%
101 During the 1920s and 1930s, Lucy Braun (1889–1971) compared the flora growing in Ohio with
flora that had grown in the same area 100 years earlier. Her research most likely added knowledge to
the scientific field of —
A virology
C genetics
B ecology
D physiology
102 Plants that can tolerate great extremes in environmental temperatures are most often found living in
F deserts
H prairies
G coastal pine forests
J island hardwood forests
103 A lichen is composed of two organisms, a fungus and a cyanobacterium. The fungus provides a
growing surface, moisture, and nutrients to the cyanobacterium. The cyanobacterium provides food
to the fungus. This relationship is considered to be an example of which of the following?
A Commensalism
C Neutralism
B Mutualism
D Parasitism
104 An ocean food chain is shown in the diagram. Which organism represents the trophic level
containing approximately 1% of the initial amount of solar energy acquired by the phytoplankton?
F Copepods
G Sand eels
H Herring
J Humans
105
A
B
C
D
106
F
G
H
J
107
A
B
C
D
F
G
H
J
108
109
A
C
B
D
110
F
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113 In 1893, a one-million acre area of the Grand Canyon National Forest Reserve was home to an
estimated 3,000 Rocky Mountain mule deer. Cattle, sheep, and horses also roamed the reserve. In
1906, government hunters killed off hundreds of mountain lions, coyotes, and bobcats when the area
was set aside as the Grand Canyon National Game Preserve. The number of Rocky Mountain mule
deer rose to over 100,000 by 1923. What was the approximate density of the mule deer in 1923?
A 1 for every acre
C 1 for every 10 acres
B 1 for every 1,000 acres
D 1 for every 100 acres
114 The graph shows the amount of pollutants removed by trees. During October, the trees were able to
remove the greatest amount of —
F
H
G
J
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A
B
C
D
116 Which level of this food pyramid represents the largest biomass?
F Algae
G Minnows
H Copepods
J Bass
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A A mushroom
B A dandelion
C A pine tree
D A caterpillar
F mushrooms
G rabbits
H green plants
J hawks
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A 50
B 10
C 70
D 30
120 A student wants to view cells under the compound microscope at a total magnification of 400X. If
the eyepiece is 10X, which of the following objective lenses should be used?
F 40X
H 100X
G 10X
J 4X
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B
C
D
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A 90
B 100
C 160
D 140
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144 Caytonia is an extinct plant that existed between 200 and 140 million years ago. It had reproductive
structures that resemble structures in modern flowering plants. How do scientists know about the
structures of this ancient extinct plant?
F Scientists study the DNA sequences of Caytonia.
G Scientists genetically engineer modern plants to produce Caytonia.
H Scientists excavate and examine the fossilized remains of Caytonia.
J Scientists observe the adaptations of plants in habitats resembling those of
Caytonia.
145 The map shows where woolly mammoth and Columbian mammoth fossils have been found in North
America. What kind of information does this map provide for paleontologists?
A
B
C
D
The range of each mammoth species
The seasonal migration routes of mammoths
Where mammoths were most hunted
Where mammoths
146 This food chain can be found in the coastal waters of Virginia. The population of which organisms in
the food chain would be the first to decline if commercial fishing over-harvested shrimp?
F Algae
G Zooplankton
H Damselfish
J Barracuda
147 Which of these best describes an organism’s ability to maintain the constant internal conditions
necessary for life?
A Homeostasis
B Stability
C Reproduction
D Adaptation
148
F
H
G
J
A May
B July
C August
D October
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150
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G
H
J
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A
C
B
D
152 A biology class wanted to develop a research project to predict the effects of a new highway on
wildflower species found in the Piedmont region of Virginia. The class could best conduct such a
study by sampling flowers found in the highway construction area —
F one year before highway construction begins
G immediately after highway construction is finished
H both before and after highway construction is completed
J during the time highway construction is taking place
153 An example of a biotic factor in the ecosystem shown below is
A the sun
B the soil
C the water
D the plants
154 The relationship between a tick and the dog it is biting is called
F predation.
H mutualism.
G parasitism.
J commensalism.
155 A scientist is examining what happens to rodents and grasses when more hawks are allowed to hunt
rodents in a field. What level of ecology is he observing?
A an organism
C a community
B a population
D an ecosystem
156 One way that pesticides have had a negative effect on ecosystems is by
F building up toxins in animals that consume plants sprayed with pesticides
G making plants that have been sprayed with pesticides unable to fix nitrogen in
soil
H preventing runoff from fields sprayed with pesticides from entering lakes and
streams
allowing plants that have been sprayed with pesticides to build up resistance
to the pesticides
157 A certain kind of protist can digest wood. It lives in the intestines of insects that fly and reproduce
rapidly. This can cause problems for the
A oil industry.
C construction industry.
B coal industry.
D transportation industry.
158 The student below is concerned with the survival of the plant in his aquarium.
J
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Which level of ecology is his focus?
F an organism
H a community
G a population
J an ecosystem
What always occurs when converting wildlife habitats into farmland?
A spread of bacterial disease
B reduction of ecosystem biodiversity
C increase in the populations of predators
D growth of insect resistance to pesticides
The higher the animal in a food chain for a particular ecosystem, the greater the concentrations of
toxins found in the animal’s body. This is often the result of
F pesticide use.
H nuclear radiation.
G nitrogen fixing.
J shrinking of habitat
Which describes a group of organisms that belong to the same species and live in the same area?
A biosphere
C ecosystem
B population
D community
A fish species lives in the coral-like tentacles of a primitive invertebrate. Scientists believe that fish
droppings and scraps of food provide nutrients for the invertebrate. What additional information
would make this a mutualistic relationship?
F The fish protects the invertebrate from predators
G The fish uses the invertebrate as a nest for their eggs
H The invertebrate reproduces less often because of the fish
J The invertebrate grows more slowly in the presence of the fish
In which set is a biotic factor paired with an abiotic factor?
A producers and sunlight
C herbivores and carnivores
B decomposers and plants
D temperature and humidity
164 A biology class is conducting a year-long field study on animals in a nearby pond. The chart below
shows each group’s topic.
Group Topic
I
Competition among turtles for mates
II
The predator-prey relationship between turtles and fish
III
Length of time required by frogs to complete metamorphosis
IV
The effects of water temperature on the hatching success of toad eggs
Which group will provide the most information about a community?
F Group I
H Group III
G Group II
J Group IV
165 Which biome has the greatest amount of biodiversity?
A boreal forest
C tropical rain forest
B tropical savanna
D temperate grasslands
166 Which question could a student investigate to determine the effects of a biotic factor on a pond
community?
F How does the number of predators affect the fish population?
G How do nitrogen levels affect the amount of algae in the pond?
H How does water temperature affect the respiration rate of frogs?
J How does the pH of water affect the hatching of mosquito eggs?
167 Which technology allows scientists to track bird migration patterns through Arkansas?
A clipping bird wings
B capturing and banding birds
C distributing bird-hunting licenses
D following bird flockswith helicopters or airplanes
168 How do exergonic reactions differ from endergonic reactions?
F Exergonic reactions absorb energy, while endergonic reactions release
energy.
G Exergonic reactions release energy, while endergonic reactions absorb
energy.
H Exergonic reactions occur only in plants, while endergonic reactions occur
only in animals.
J Exergonic reactions produce carbon dioxide, while endergonic reactions
require carbon dioxide.
169 Which technology was specifically developed to lessen the effects of human population growth on
the environment?
A hybrid cars
C stem cell research
B medical forensics
D digital video and television
170 What is a difference in how primary and secondary succession begin?
F Only secondary succession begins on bare rock or new land
G Only primary succession begins in a previously inhabited area
H Only secondary succession begins with larger trees and bushes
J Only primary succession begins with pioneer organisms such as lichens
171 The organism in the terrestrial food web that corresponds to the krill in the marine food web is
labeled X. Which of the following organisms is most likely organism X?
A
B
C
D
Mouse
Fox
Oak tree
Hawk
172 A hurricane sweeps across a small Caribbean island, killing 50 percent of the herbivore species on
the island. Which of the following is the most immediate result?
F a reduction in biodiversity
G an acceleration of the carbon cycle
H an increase in predator populations
J a decline in decomposer populations
173 Which of the following is a nonenvironmental factor that might cause a population to decrease in
size?
A emergence of disease resistance
B increased availability of a food source
C decreased predation
D increased competition
174 Scientists are investigating the cause of the large increase in atmospheric carbon dioxide
concentration since about 1800. Which of the following provides the best explanation for the
increase?
F eruptions of large volcanoes
G use of fossil fuels by humans
H natural fluctuations of climate
J photosynthesis by phytoplankton
175 The following section focuses on the interactions of organisms in a food web.
A partial food web for organisms in Yellowstone National Park is shown below.
Which process do the animals in the food web use to convert energy from food into ATP?
A cellular respiration
C photosynthesis
B osmosis
D transcription
176 Which organism in the food web is classified into kingdom Fungi?
F Idaho fescue
H migratory grasshopper
G king bolete
J yellow-bellied marmot
177 Which of the following organisms is a secondary consumer in this food web?
A yellow-bellied marmot
C least chipmunk
B strawberry plant
D king bolete
178 Part of a tundra food web is shown below
Which of the following describes the relationship between the sedge and the arctic hare?
F competition
H mutualism
G host-parasite
J producer-consumer
179 Which of the following explains why legume plants are less likely than other terrestrial plants to
experience nitrogen limitation?
A Legume plants need less nitrogen than other plants do.
B Legume plants have nitrogen-fixing bacteria on their roots.
C Legume plants catch insects to supply themselves with nitrogen.
D Legume plants can absorb nitrogen directly from the atmosphere.
180 Which of the following lists identifies organisms that are producers in food webs?
F algae, ferns, sunflowers
G mushrooms, bacteria, earthworms
H termites, red foxes, shrews
J woodpeckers, cardinals, grasshoppers
181 A builder is proposing a new housing development in an area of western Massachusetts.
Construction of the housing development will destroy the wetland habitat in the area. Which of the
following would be the most likely consequence of the wetland’s destruction?
A The wetland plant species would disperse to adjacent meadow habitats.
B The populations of wetland animals would be unable to survive in that area.
C The wetland animal species would survive by interbreeding with non-wetland
species.
D The populations of wetland plants would evolve to disperse seeds by wind
rather than water.
182 Which of the following relationships is an example of mutualism?
F A lion eats a gazelle.
G A virus uses both a bird and a horse as hosts.
H A bacterium breaks down dead plant materials.
J A bird eats food particles from a crocodile’s teeth.
183 Leaves fall from deciduous trees in autumn. The carbon in these leaves is returned to the atmosphere
through which of the following processes?
A condensation
C photosynthesis
B decomposition
D transpiration
184 A marine food web is shown below
F
H
G
J
185 Major natural events, such as volcanic eruptions, significantly change the environmental conditions
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of the areas where the events occur. What happens to local populations that are unable to adapt to the
new conditions or to move to other areas?
A They become extinct
B They undergo rapid mutations
C They develop a scavenger lifestyle until conditions change
D They interbreed with the populations of other species that have remained there
During one growing season, 5000 square meters of corn plants transpires approximately 1.85 million
liters of water. The water lost from the plants via transpiration goes directly to which of the
following?
F insects
G the soil
H streams
J the atmosphere
Black terns are a species of bird living in marshes, ponds, and marshy lakes. They feed on insects,
fish, and crustaceans. They usually make their nests on loose, floating vegetation. Which of the
following environmental changes would most likely decrease the size of the black tern population?
A A competing bird population decreases in size.
B Fish species have a more successful breeding season than usual.
C A new plant species invades the environment and creates a dense cover of vegetation.
D Insect larvae experience lower than average rates of predation and survive to adulthood.
Which statement is an example of a law of nature?
F Amphibians evolved from fish living in shallow ponds.
G A plant will be healthier when fertilizer is added to the soil each day.
H The growth of a child is stunted when too much caffeine is consumed.
J The genes for a trait separate into different gametes during gamete formation.
Which is a biotic factor affecting an ecosystem?
A pH of rain
C types of vegetation
B daily temperature
D average precipitation
A population of salamanders that live in a river require clear, fresh water to survive. A flood causes
tons of sediment to be suspended in the river. Which of these most likely will happen to the
salamander population?
F The salamanders will adapt to life on land
G The salamanders will move to another river
H The salamanders will adapt to living in the muddy water
J The salamanders will decrease in number because of the water quality
Which of the following will most likely result if all of the primary consumers are removed from this
ecosystem?
A Prairie rattlesnakes will become herbivores
B Golden eagle and kit fox populations will decrease
C Sagebrush grasshoppers will consume soil bacteria
D Silk grass and sand sagebrush populations will decrease
Plants absorb solar energy during photosynthesis. The graph below represents how this energy is
distributed in some plants.
Which of the following statements describes what
happens to the energy represented by the section
labeled X?
F It is recycled to the Sun
G It is consumed by decomposers
H It is lost to the soil and the atmosphere
J It is used for cellular respiration and
maintenance
193 In traditional landscaping, leaves are raked off the ground and bagged. In which of the following
ways does this practice most significantly disrupt natural nutrient cycling?
A It carries away microorganisms that can perform nitrogen fixation
B It reduces the rate of oxygen and carbon cycling via photosynthesis
C It prevents carbon, oxygen, and nitrogen from being returned to the soil
D It increases the amount of carbon dioxide that is released to the atmosphere
194 In the past 100 years, levels of atmospheric carbon dioxide have increased as the result of the
burning of fossil fuels. Other processes in the carbon cycle have absorbed some of the carbon
released by this combustion. Which of the following most likely have absorbed excess carbon
released by combustion?
F animals
H plants
G glaciers
J rocks
195 When spring and summer conditions are warm and rainy, mosquito populations often become quite
large. Which of the following statements best helps to explain this relationship?
A Mosquito larvae eat organic debris
B Adult male mosquitoes feed on plant nectar
C Mosquitoes are attracted to warm-blooded animals
D Female mosquitoes lay their eggs in pools of water
196 The graph below shows changes in the sizes of four animal populations over a 16-year period.
In which population was birthrate most likely greater than death rate from year 8 to year 12?
F population 1
H population 3
G population 2
J population
197 Which of the following roles do nitrogen-fixing bacteria serve in the nitrogen cycle?
A They concentrate nitrogen in the atmosphere
B They absorb nitrogen from the wastes of animals
C They convert nitrogen into a form that plants can use
D They release nitrogen from the bodies of decaying organisms
198 Which of the following best explains why tropical insects may be at greater risk for extinction from
global warming than insects from higher latitudes?
F Many tropical insects lay eggs year-round
G Tropical insects include more pollinator species
H Many tropical insects are herbivores rather than carnivores
J Tropical insects have narrower ranges of tolerance for temperature changes
199 In Asia, human population growth and land development have fragmented forest habitats. Because
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of this fragmentation, tigers have become geographically isolated in small populations, and the tigers
repeatedly mate within the same small population of tigers. Which of the following is the most likely
impact this isolation will have on tiger populations?
A Genetic diversity of each tiger population will decrease, threatening survival.
B Adaptation of each tiger population to its present environment will occur rapidly.
C The tigers in each population will breed more often, increasing population size.
D The tigers in each population will mate with closely related species to maximize
breeding success.
A major reservoir for oxygen is the atmosphere. Which of the following processes adds oxygen to
the atmosphere?
F cellular respiration
H decomposition
G combustion
J photosynthesis
Which of the following is an example of emigration?
A A small number of hummingbirds leave an island
B A large number of hummingbirds die in a hurricane
C A species of hummingbird lays its eggs in the summer months
D A species of hummingbird adapts to its environment over time
Sea otters are small marine mammals that prey on fish, clams, crabs, and sea urchins. Sea otters’
natural predators include bears, sharks, and killer whales, but humans have also threatened sea otter
populations. Hunting of sea otters for their fur severely reduced sea otter populations in the 18th and
19th centuries. After laws and programs were put into place to protect sea otters, their populations
started increasing. Some sea otter populations in Alaska are now decreasing again. Which of the
following is the most likely cause of these decreases?
F greater numbers of killer whales
G larger populations of sea urchins
H less competition from other marine mammals
J limited immigration of sea otters from California
A picture of a horseshoe crab is below. Horseshoe crabs are arthropods, related to crustaceans,
insects, and spiders.
In the 1990s, the harvesting of horseshoe crabs for fishing bait and biomedical use led to a significant
decrease in the size of horseshoe crab populations on the Mid-Atlantic coast of the United States.
Recovery efforts for the horseshoe crab populations are most challenged by which of the following?
A Horseshoe crabs are most active at night.
B Horseshoe crabs have to shed their exoskeletons as they grow.
C Horseshoe crabs can live on the Atlantic coast from Maine to Mexico.
D Horseshoe crabs take nine to twelve years to reach maturity and reproduce.
204 Which processes are part of the carbon cycle?
F photosynthesis and respiration
H osmosis and diffusion
G mitosis and meiosis
J transpiration and evaporation
205 Which causes the most loss of biodiversity on Earth?
A air pollution
C the greenhouse effect
B habitat destruction
D ozone depletion
206 Which biotic factor affects the number of animals in a population?
F kinds of predators
H average temperature
G amount of oxygen
J amount of water
207 Which is a benefit of planting different crops on the same land throughout the year?
A It slows the loss of minerals from the soil.
B It adds iron to the soil.
C It increases water runoff.
D It increases biodiversity
208 Which would most help to protect an endangered species?
F Make the hunting season for that species longer
G Import additional species to encourage competition
H Set aside protected lands for the species to grow and reproduce
J Start a breeding program in captivity
209 What will most likely happen if the human population continues to grow at the current rate?
A There will be fewer natural resources available
B There will be a decrease in endangered species
C There will be a decrease in water pollution
D There will be more available resources
210 What is the function of autotrophs in the carbon cycle?
F to use oxygen to produce glucose
G to take in excess water
H to use carbon dioxide to produce glucose
J to feed on herbivores
211 What will most likely happen if the human population continues to grow at current rates?
A There will be fewer natural resources available for future generations.
B There will be an increase in nitrogen levels in the atmosphere.
C There will be a decrease in water pollution.
D There will be an increase in the number of strong hurricanes.
212 A sea turtle has washed up on a remote section of a beach. This is known as a “stranding.” Stranding
occurs when a dead, sick or injured sea turtle washes up on the shoreline. Which statement best
explains why “stranding” should be reported immediately to local authorities?
F The information can be very useful to biologists and managers who are trying to protect the
species.
G The information can be very useful to protect sea turtles from predators.
H The information can be very useful to local fishermen who try to catch fish that sea turtles eat.
J The information can be very useful to tourists who may want to keep sea turtles as pets.
213 The yucca plant releases a strong scent at night when the yucca moth is active. The yucca moth,
attracted by the scent, gathers pollen from the yucca flower. The yucca moth then deposits her eggs
and the pollen on another plant. This ensures that the plant will be cross-pollinated and that the yucca
moth larvae have a steady food supply. Which relationship does this best illustrate?
A commensalism
C parasitism
B mutualism
D predation
214 The construction of a new coal-burning power plant would have the greatest impact on which
environmental issue?
F depletion of the ozone
H release of radiation
G production of acid rain
J increase in deforestation
215 A field ecologist wants to determine the interactions of various populations of organisms living in a
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large grassland field. Which method is best for conducting this study?
A consulting with local farmers about the diversity of organisms in the field
B dividing the field in half, walking over it, counting organisms, and then doubling the numbers
C walking over the entire field, collecting the organisms, and then compiling a total
D observing the behaviors of different types of organisms several times during the year
Which environmental factor would cause the greatest decrease in the number of species of plants and
animals living in some of the lakes in the United States?
F increase in dissolved oxygen levels H ozone destruction
G global warming
J acid rain
Blackberry plants are found in forest edge habitats. How could blackberry plants limit the population
of salmonberry plants growing in the same habitat?
A Blackberry plants increase oxygen in the ecosystem
B Blackberry plants lack flowers that attract bees
C Blackberry plants produce dark purple berries
D Blackberry plants compete for resources
Which event might be evidence that a forest edge habitat is in equilibrium instead of a disturbance?
F A dead tree providing nutrients for a young tree
G A bird species leaving as temperatures increase
H A landslide damming the stream in the habitat
J A flood washing away topsoil from the ground
Which of the diagrams below shows an example of secondary succession in an ecosystem?
A
B
C
D
220 The biome populated by cone-bearing trees such as pine, spruce, and fir is the
F deciduous forest
H savanna
G coniferous forest
J tundra
221 The graph below shows changes in truffle harvesting in an oak forest over a period of 40 years.
Which statement BEST describes the relationship between the oak forest and the truffle population?
A As the amount of oak forest declined, the number of truffles available for harvest increased
B As the amount of oak forest declined, the number of truffles available for harvest also declined
C The number of truffles available for harvest is inversely proportional to the area of oak forest
D Even though both the area of oak forest and number of truffles decreased, there is no relationship
between the two
222 Which of the following correctly describes the way animals get their nutrition?
F They make their own food through a process called photosynthesis
G They eat other organisms, their parts, or products
H They decompose dead plant matter
J They make their own food through a process called cellular respiration
223 Look at the diagram below.
Which of the following is the correct flow of energy?
A The crab gets energy from eating plants
B The heron gets energy from eating plants
C The crab gets energy from eating the heron
D The heron gets energy from eating the crab
224 Which of the following is an example of how a change in climate can affect the equilibrium of an
ecosystem?
F When the climate change involves a decrease in temperature, more tropical plants can invade an
ecosystem.
G The species diversity of the insects in an ecosystem will remain constant as the temperature
increases.
H A change in temperature will likely affect the ability of native species to withstand infectious
diseases.
J With increasing storms, additional energy is available for photosynthesis.
225 Mold and mushrooms are organisms that help recycle materials within an ecosystem.
How would an ecosystem with few recycling organisms be affected?
A It would be able to support more life
B It would have more materials and resources available
C It would have fewer materials available to organisms
D It would contain more plants
226 By drilling sediment cores from the ocean floor and studying them, scientists have learned much
about ancient carbon dioxide levels and climate. A study in 2004 found that the waters around the
North Pole 55 million years ago were as warm as the waters in today’s tropics. The researchers also
found that the concentration of carbon dioxide 55 million years ago was 2,000 parts per million
(ppm), whereas today, the concentration is 380 ppm. Which hypothesis does this finding support?
F High levels of atmospheric carbon dioxide result in global warming.
G Earth’s climate does not change.
H Many erupting volcanoes gave off huge quantities of carbon dioxide 55 million years ago.
J Today’s levels of atmospheric carbon dioxide are not a cause for concern.
227 Examine the energy pyramid shown below.
Each level of the energy pyramid above contains about 90% less energy than the level below it. The
energy that is not passed on to the organism above it is used in the life processes of the organism or
released into the environment. A certain sample of plants contains 490 joules (J) of energy. Based on
the energy pyramid above, approximately how much of that energy remains in the level containing
rats?
A 4.90 J
C 490 J
B 49.0 J
D 4,900 J
228 Examine the graph below.
In 1988, a large shopping mall was built in the area where the sparrows lived. According to the
information in the graph, how did this affect the sparrow population over a period of time?
F The sparrow population increased because humans fed the sparrows
G The sparrow population was unaffected by the shopping mall
H The sparrow population increased because predators were taken away
J The sparrow population decreased because of habitat destruction
229 A group of scientists studied the effects of pesticides on a local ecosystem. Over a number of years,
they estimated the size of the populations of insect pests and beneficial species of insects in one area.
Their findings from the first years of their study are illustrated below.
Which statement BEST describes the relationship between the two populations of insects before the
introduction of pesticides?
A As the population of the beneficial insects increased, so did the population of
the pests
B As the population of the beneficial insects decreased, so did the population of
the pests
C As the population of the beneficial insects increased, the population of the
pests decreased
D The populations do not appear to have had an effect on each other
230 Mistletoe grows on trees. It sends its roots into the tree and uses the nutrients that could otherwise be
used by the tree. If mistletoe benefits from the relationship and the tree is harmed, what kind of
relationship exists between the two organisms?
F commensalism
H parasitism
G mutualism
J predation
231 Which of the following environmental effects CANNOT be attributed to acid rain?
A damage to trees and a decline of forest communities
B an increase in CO2 in Earth’s atmosphere
C damage to historic buildings and monuments
D death of aquatic organisms in lakes and streams
232 Which of the following circumstances will allow a population to grow?
F Emigration is greater than immigration
G The birth rate is equal to the death rate
H The death rate is higher than the birth rate
J The birth rate is greater than the death rate
233 The graph below shows the average monthly values of atmospheric carbon dioxide.
How can the dip in carbon dioxide levels shown on the graph be related to the carbon cycle?
A Increased plant growth and photosynthesis during summer months remove more carbon dioxide
from the atmosphere
B Erosion of farmland removes carbon dioxide from the air
C More carbon dioxide is dissolved in lake and ocean waters during the warm summer months
D Fewer trees are cut for firewood during warmer months
234 A carbon sink is a part of Earth’s ecosystem that stores carbon in one form or another for hundreds,
thousands, and even millions of years. Forests and oceans are known to be carbon sinks. Which of
the following marine organisms play a major role in making the ocean a carbon sink?
F whales, because they are large and can take up large amounts of carbon
G gelatinous zooplankton, because their biomass consists largely of water
H marine mammals, because they are high up on the food chain
J phytoplankton, because they are extremely numerous and they use carbon
dioxide during photosynthesis
235 Termites use the cellulose in wood as the main energy source in their diet. However, termites do not
produce the enzymes necessary to break down the sugars in cellulose. Bacteria living in the digestive
system of termites break down cellulose for the termites. Both the termites and the bacteria benefit
from this relationship. This is an example of what type of relationship?
A commensalism
C parasitism
B mutualism
D predation
236 Infer why certain types of fungi in a landfill might be helpful to the environment.
F Fungi reduce unpleasant odors
G Fungi give off less methane gas than other decomposers
H Some fungi can break down tough plastics
J Fungi remove carbon dioxide from the atmosphere
237 Rosa compared the arthropod that she collected with a dead specimen that is part of her teacher’s
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labeled collection of arthropods. The dead specimen, labeled an arachnid, looks identical to the live
arthropod, except that the dead specimen has only six legs and is asymmetrical. Which of the
following is MOST LIKELY true?
A The live arthropod is an insect that has grown extra legs due to a mutation
B The dead specimen is a nymph and is missing legs because it did not fully mature
C The dead specimen is an insect, because it has six legs and an asymmetrical body plan
D The dead specimen is an arachnid that has been damaged. Two of the legs are missing
In which biogeochemical cycle do the symbiotic bacteria in the roots of many plants play an
important role?
F carbon cycle
H phosphorus cycle
G nitrogen cycle
J water cycle
Which of the following is an example of coevolution?
A plants producing spines, thorns, or nettles to protect themselves against
predators
B birds leaving the nest where they were born
C animals learning to graze for food
D stomach enzymes operating optimally in acid environments
Researchers have found that the Abert’s squirrel population on the South Rim of the Grand Canyon
fluctuates from year to year, increasing one year and decreasing the next. Which of the following
factors would cause the squirrel population to grow?
F Emigration is greater than immigration
G The birth rate is equal to the death rate
H The death rate is higher than the birth rate
J The birth rate is greater than the death rate
Which of the following is an environmental effect associated with acid rain?
A damage to trees and a decline of forest communities
B an increase in CO2 in Earth’s atmosphere
C lower levels of pollution
D increase in number of aquatic organisms in lakes and streams
Which organism has the same role as lions in the savanna?
F algae in the ocean
H grasshopper in the prairie
G coyote in the chaparral
J tree frog in the tropical rain forest
In which biome would you find most nocturnal animals?
A desert
C taiga
B savanna
D tundra
244 Look at the map of Earth’s climate zones below. Where are biomes with the largest number of plant
and animal species located?
F
G
H
J
in the polar zones
in the tropical zones
in the temperate zones
only in the northern portion of the tropical zones
245 Radiant energy from the sun is converted to chemical energy by the process of
A diffusion
C photosynthesis
B osmosis
D mitosis
246 The Yellowstone area contains organisms representing all trophic levels, including plants, algae,
mosses, fungi, blue jays, fish, and grizzly bears. Which sequence BEST represents the transfer of
energy through Yellowstone trophic levels?
F blue jay to moss to fungi to plant
G fungi to moss to algae to fish
H plant to blue jay to algae to grizzly bear
J algae to fish to grizzly bear to fungi
247 Examine the diagram below.
What process is illustrated?
A succession
C pioneer speciation
B ecological bottleneck
D ecosystem boundaries
248 Some plants have stems that can hold water and carry on photosynthesis, and almost no leaves. In
which type of habitat would this be important?
F grassland
H swamp
G rainforest
J desert
249 When a tick feeds on a human blood, what type of ecological interaction exists?
A mutualism
C succession
B commensalism
D parasitism
250 An animal that feeds on plants is, at the least, in which of the following?
F first trophic level
H third trophic level
G second trophic level
J fourth trophic level