Deck 35: Nature of Ecosystems

Question 1

How are omnivores, carnivores, and herbivores similar?

A) They are all producers.
B) They are all consumers and produce oxygen.
C) They all produce their own food.
D) They all produce oxygen.
E) They are all consumers and produce carbon dioxide.

Answer 1

E

Question 2

The primary producers in an ecosystems are also called

A) autotrophs.
B) herbivores.
C) consumers.
D) carnivores.
E) heterotrophs.

Answer 2

A

Question 3

Once a nutrient enters an ecosystem, it

A) must remain in that ecosystem.
B) can cycle endlessly in that ecosystem.
C) must leave that ecosystem to enter into an organism.
D) cannot leave that ecosystem.
E) can only leave that ecosystem if it is carried by a living organism.

Answer 3

B

Question 4

Humans are biologically adapted to be

A) omnivores.
B) herbivores.
C) decomposers.
D) autotrophs.
E) carnivores.

Question 5

If the total amount of solar energy captured by plants in an ecosystem is 10,000 kilocalories, how much of this energy will be available to the next trophic level?

A) 10,000 kilocalories.
B) 1,000 kilocalories.
C) 100 kilocalories.
D) 10 kilocalories.
E) 1 kilocalorie.

Question 6

Animals that feed on both plants and other animals are called

A) herbivores.
B) carnivores.
C) omnivores.
D) decomposers.
E) detritivores.

Question 7

The biogeochemical cycle(s) that cannot be categorized as either sedimentary or gaseous is/are the

A) nitrogen cycle.
B) carbon cycle.
C) water cycle.
D) phosphorus cycle.
E) carbon and nitrogen cycles.

Question 8

Energy flow in an ecosystem begins with

A) omnivores.
B) herbivores.
C) decomposers.
D) autotrophs.
E) carnivores.

Question 9

Which of the following is comprised of a community of organisms, plus its physical environment?

A) food chain
B) habitat
C) niche
D) ecosystem
E) trophic level

Question 10

In the carbon cycle, coal serves as an atmospheric reservoir of carbon.

Question 11

Which of the following organisms would be considered a decomposer?

A) green algae
B) green plant
C) caterpillar
D) bird
E) mushroom

Question 12

Which organism eats only plant foods?

A) omnivore
B) herbivore
C) decomposer
D) autotroph
E) carnivore

Question 13

Fungi and bacteria are detritus-feeders, also known as

A) omnivores.
B) herbivores.
C) decomposers.
D) autotrophs.
E) carnivores.

Question 14

The only heterotrophs required for an ecosystem to function are

A) omnivores.
B) herbivores.
C) decomposers.
D) autotrophs.
E) carnivores.

Question 15

Which kind of organism would be most likely to perform photosynthesis?

A) omnivore
B) herbivore
C) decomposer
D) autotroph
E) carnivore

Question 16

An ecosystem consists of what two components?

A) grazing and detritus food chains
B) habitat and niches
C) biotic and abiotic factors
D) trophic and eutrophic factors
E) water and temperature

Question 17

The primary consumers that feed directly on green plants are called

A) omnivores.
B) decomposers.
C) herbivores.
D) carnivores.
E) producers.

Question 18

A disruption in which biogeochemical cycle will lead to cultural eutrophication?

A) phosphorus
B) carbon
C) nitrogen
D) hydrological
E) All of the answer choices are correct.

Question 19

At which point in a biogeochemical pathway are elements unavailable to plants?

A) when the element is located in a reservoir
B) when the element is located in the exchange pool
C) when the element is dissolved in water
D) when the element is located in the soil
E) when the element is located in the atmosphere

Question 20

Which of the following is a biotic factor in an ecosystem?

A) trees
B) inorganic nutrients
C) water availability
D) temperature
E) sunlight

Question 21

Which of the following would be an organism at the base of a detrital food web?

A) fox
B) salamander
C) beetle
D) sunflower
E) hawk

Question 22

The ultimate source of energy for the majority of organisms on Earth, including humans, is

A) heat from burning fuels.
B) heat from muscle contraction.
C) sunlight.
D) electric light.
E) ultraviolet light.

Question 23

In a certain ecosystem, caterpillars eat grass. Field mice eat the caterpillars and seeds from the grass. Snakes eat the mice. Hawks eat both the snakes and mice. Such an arrangement would be considered a(n)

A) food web.
B) food chain.
C) ecosystem.
D) first trophic level.
E) second trophic level.

Question 24

What eventually happens to the energy that is passed from one trophic level to the next in a food chain?

A) It recycles back to the producers.
B) It results in a much larger decomposer population.
C) It is dissipated into the atmosphere in the form of heat.
D) It is recaptured by another food chain.
E) It is eventually sealed in fossil fuels such as coal and oil.

Question 25

When a plant produces food by photosynthesis, what is the fate of food stored as sugars, starches, etc.?

A) All of the food stored by plants is eventually consumed by animal consumers.
B) All of the food stored by plants is eventually consumed by either animals or decomposers.
C) Most of the plant is consumed by animals and very little is consumed by decomposers.
D) A portion of the food is used by the plant itself in cellular respiration and the rest is consumed by animals or by decomposers.
E) A majority of the food is used by the plant itself in cellular respiration and very little is consumed by animals or by decomposers.

Question 26

Which sequence illustrates the most plausible food chain?

A) algae, insect larvae, fish, humans
B) algae, fish, insect larvae, humans
C) insect larvae, algae, fish, humans
D) fish, insect larvae, algae, humans
E) humans, fish, insect larvae, algae

Question 27

A detritus food chain begins

A) in the ocean.
B) with a producer.
C) with decaying matter.
D) with air pollution.
E) with fungi.

Question 28

In a grazing food chain

A) all the consumers are primary consumers.
B) primary consumers eat photosynthetic organisms.
C) primary consumers eat detritus.
D) tertiary consumers eat photosynthetic organisms.
E) secondary consumers eat detritus.

Question 29

Which of the following statements inaccurately describes a complex food web?

A) It remains stable.
B) Populations tend to remain about the same size.
C) Energy levels remain about the same for all trophic levels.
D) Inputs are constant and outputs are minimal except for heat.
E) Most of the energy entering the system maintains the whole community.

Question 30

Which of the following can be classified as either a secondary or tertiary consumer?

A) producer
B) herbivore
C) photoautotroph
D) autotroph
E) carnivore

Question 31

The only biogeochemical cycle that influences food webs is the carbon cycle.

Question 32

In an ecosystem, which of the following is/are constantly recycled?

A) carbon
B) nitrogen
C) water
D) phosphorus
E) All of the answer choices describe aspects of an ecosystem that are constantly recycled.

Question 33

Most natural food chains are only four or five links long. The number of trophic levels is limited because

A) there are more predators than herbivores.
B) the efficiency in the conversion of food eaten at each level is very low, about 10 percent.
C) winter kills off most insects and stops the food chains.
D) space in the ecosystem is limited and so very few larger organisms can live there.
E) nutrients stop cycling after the fourth or fifth trophic level.

Question 34

What happens to the amount of available energy as you progress up the food pyramid?

A) The amount of energy decreases.
B) The amount of energy increases.
C) The amount of energy stays the same.
D) The amount of energy first decreases and then finally increases.
E) Energy does not move from one trophic level to the next.

Question 35

Settlers move into an area and harvest most of the foxes for fur. They are likely to see

A) hawks die out.
B) squirrel populations increase.
C) grasshopper populations increase.
D) hawk populations immediately increase.
E) grasshoppers decrease.

Question 36

When settlers move into a wooded area, they slash and burn the woods, increasing grass production. Initially, they are likely to see

A) foxes increase.
B) squirrels increase.
C) grasshoppers increase.
D) hawks decrease.
E) grasshoppers decrease.

Question 37

How is a carnivore like an herbivore?

A) Both pass on all energy received to the next trophic level.
B) Both tend to produce nutrients for plants.
C) Both pass on much less energy to the next trophic level than they received.
D) Both are able to convert organic compounds to ATP without loss of energy.
E) Both feed on detritus.

Question 38

In the following food chain, which organism is a secondary consumer? grass → rabbits → snakes → hawks → foxes

A) grass
B) rabbits
C) snakes
D) hawks
E) foxes

Question 39

Which of the following is necessary to maintain a balanced (stable) ecosystem?

A) Matter (i.e., elements) has to cycle.
B) There must be an outside energy source.
C) Various populations of producers and consumers must be proportional.
D) Energy must be allowed to flow through the ecosystem.
E) All of the answer choices describe necessary factors for maintaining a balanced ecosystem.

Question 40

The base of an ecological pyramid represents the

A) producer trophic level.
B) primary consumer trophic level.
C) secondary consumer trophic level.
D) top predator trophic level.
E) decomposer trophic level.

Question 41

The conversion of nitrate to nitrogen gas is achieved by

A) denitrifying bacteria.
B) leguminous bacteria.
C) nitrogen-fixing bacteria.
D) nitrate-producing fungi.
E) nitrite-producing fungi.

Question 42

Consider the components of a four-step food chain: producers, herbivores, carnivores, top predators. If everything is eaten at each level, how much of the energy stored by a producer is passed to the top predator?

A) 100%
B) 10%
C) 1%
D) 0.1%
E) 0.01%

Question 43

Based on your understanding of ecological pyramids, is the annual productivity of a typical urban (city) backyard large enough to support a house cat restricted to the backyard or will the cat require food supplements in order for it to survive?

A) The producer productivity is large enough for just the one cat to survive.
B) The cat must be fed additional food or it will starve.
C) The cat will be able to survive if there is at least one fruit tree in the backyard.
D) The cat will be able to survive if the backyard consists only of grass.
E) The producer productivity can support the cat, along with several offspring.

Question 44

How much of the water on Earth is fresh water?

A) 3%
B) 10%
C) 30%
D) 50%
E) 90%

Question 45

Inverted ecological pyramids can occur in what habitat?

A) forest canopies
B) deserts during rare rainfalls
C) aquatic ecosystems
D) any ecosystem disturbed by human activity
E) If studied closely, inverted pyramids never occur naturally.

Question 46

Nitrification refers to the production of

A) nitrogen gas.
B) nitrate.
C) nitrite.
D) ammonia.
E) ammonium.

Question 47

In the carbon cycle, carbon is returned to the atmosphere by

A) respiration of animals and plants.
B) photosynthesis.
C) evaporation of water.
D) glycolysis.
E) denitrification.

Question 48

Approximately what percentage of the energy in one trophic level becomes incorporated into the next level?

A) 1%
B) 10%
C) 30%
D) 60%
E) 100%

Question 49

Which of the following processes removes carbon from the atmosphere?

A) photosynthesis
B) burning fossil fuels
C) removing trees from the forest
D) cellular respiration in plant cells
E) cellular respiration in animal cells

Question 50

Carbon first enters the food web in

A) humans.
B) vertebrates.
C) invertebrates.
D) green plants.
E) soil bacteria.

Question 51

An inverted energy pyramid for an ecosystem, one where there are more consumers than producers at a given point in time, is possible if which of the following is true?

A) Producers are reproducing more slowly than consumers.
B) There is intense sunlight for long periods of time, as in the tropics.
C) Producers are reproducing much more rapidly than consumers.
D) Decomposers are reproducing much more rapidly than consumers.
E) Consumers are reproducing more rapidly than producers.

Question 52

Plants obtain nitrogen directly from the air.

Question 53

The two general categories of biogeochemical cycles are

A) energy and matter.
B) terrestrial and aquatic.
C) gaseous and sedimentary.
D) chemical and physical.
E) organic and inorganic.

Question 54

The phosphorous cycle is not affected by human activities.

Question 55

Chemical cycling of inorganic nutrients in a natural ecosystem would occur with or without

A) a reservoir for the element in the earth.
B) the biotic community and its food chains.
C) an exchange pool from which producers draw nutrients.
D) weather.
E) animals.

Question 56

Which pyramid illustrates that at each successive trophic level there is a decreasing amount of energy available?

A) a pyramid representing the number of organisms at each level
B) biomass pyramid of organisms at each level
C) ecological pyramid
D) food chain
E) food web

Question 57

Your friend tells you that some of the carbon atoms in his body were previously part of another living organism. This is

A) possible only if he is a cannibal.
B) possible since carbon cycles through the ecosystem.
C) impossible since carbon can't enter a living system more than once.
D) highly unlikely since carbon does not cycle like other elements.
E) unlikely because we don't have any carbon atoms in our bodies.

Question 58

Which statement about the hydrologic cycle is accurate?

A) The cycle demonstrates that it is impossible to run out of fresh water for human use.
B) Some water evaporates from land and from plants.
C) All water molecules that evaporate from the ocean precipitate on land and move by gravity through groundwater to the ocean again.
D) Once water sinks into the ground, it is safe from human exploitation or pollution until it has rejoined the ocean.
E) The main source of water in the atmosphere is from evaporation over landmasses.

Question 59

Which of the following statements regarding the carbon cycle is/are true?

A) Terrestrial plants take up carbon dioxide from the air.
B) Algae produce food for themselves and for heterotrophs.
C) When organisms respire, a portion of carbon is returned to the atmosphere as carbon dioxide.
D) The amount of bicarbonate in the water is in equilibrium with the amount of carbon dioxide in the air.
E) All of the answer choices regarding the carbon cycle are true.

Question 60

When withdrawal from an aquifer exceeds the rate of recharge, this is known as

A) transpiration.
B) negative hydrology.
C) establishing a reservoir.
D) increasing the transfer rate.
E) groundwater mining.

Question 61

Atmospheric carbon serves as a(n)

A) exchange pool for carbon that is available to plants for photosynthesis.
B) long-term storage reservoir that becomes available to plants through the action of bacteria.
C) exchange pool for carbon that is made available to plants through the action of bacteria.
D) reservoir of carbon that will eventually be released into the ecosystem through the process of weathering.
E) storage reservoir of carbon that is part of the sedimentary cycle of carbon.

Question 62

You buy a house on a small inland lake and your front lawn ends at the water's edge. A lawn care company representative suggests you fertilize the lawn to keep it lush and green. You agree to the treatment and then, two weeks later, the lake is covered in green algae. The most likely cause of the algae problem is

A) nitrogen.
B) nitrites.
C) sulfates.
D) phosphates.
E) carbon.

Question 63

Living organisms need phosphate to produce

A) DNA.
B) sugar.
C) amino acids.
D) lipids.
E) steroids.

Question 64

Which of the following is usually a limiting factor (nutrient) for plants?

A) nitrogen
B) nitrites
C) carbon dioxide
D) phosphates
E) hydrogen

Question 65

Atmospheric CO₂ combines with water to produce bicarbonate, which is

A) a cause of the greenhouse effect.
B) ozone.
C) a source of carbon for algae.
D) photochemical smog.
E) a thermal inversion.

Question 66

Explain the steps in the hydrological cycle.

Question 67

Which biogeochemical cycle is directly associated with fossil fuels?

A) carbon
B) nitrogen
C) hydrological
D) phosphorus
E) All of the answer choices are correct.

Question 68

List the four biogeochemical cycles that need to be in balance in order to have stable ecosystems.

Question 69

The greenhouse effect is

A) due to destruction of the ozone layer which has increased our exposure to sunlight.
B) caused by plant life and photosynthesis.
C) due to atmospheric gases trapping and radiating heat back to Earth.
D) due to the acidification of the oceans.
E) not affected by human activities.

Question 70

In a grassland biome, which organism would most likely be at the highest trophic level?

A) hawk
B) big bluestem grass
C) sparrow
D) caterpillar
E) mouse