Deck 35: Nature of Ecosystems

Question 1

Humans are biologically adapted to be

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

Answer 1

A

Question 2

Given that most nutrients can dissolve into water,which of the following statements is false?

A)Runoff water can pollute a pond,stream,or lake if excess nutrients are carried in the water.
B)Water can carry nutrients into the soil,where they are available to plants through their roots.
C)Water can leach nutrients out of the soil and carry it away from an ecosystem.
D)N₂ dissolves into water droplets and is carried to the earth to be used by producers.
E)Carbon dioxide dissolves into water and is then available to aquatic producers.

Answer 2

D

Question 3

The primary consumers that feed directly on green plants are called

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

Answer 3

C

Question 4

The one nutrient that cannot be categorized as either a sedimentary or a gaseous cycle is

A)nitrogen,because it requires bacteria to convert it into a usable form.
B)carbon,because it can dissolve into water.
C)water,because it can exist as a solid,a liquid,or a gas.
D)carbon,because human activities disturb the natural cycle.
E)nitrogen,because it must be an ion to be available to producers.

Question 5

Animals that feed on both plants and other animals are called

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

Question 6

In an experiment carried out to study the energy flow through an ecosystem,scientists measured the total solar energy captured by plants to be 10,000 kilocalories.The portion of this available to the next trophic level will be

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

Question 7

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

A)the food chain
B)inorganic nutrients
C)water availability
D)temperature
E)sunlight

Question 8

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.

Question 9

The three locations where a nutrient may be found in an ecosystem are in order of

A)nutrient/producer,reservoir/long-term storage,and organism/short-term storage.
B)exchange pool/long-term storage,reservoir/nutrients for producers,and organisms/short-term storage.
C)exchange pool/short-term storage,reservoir/nutrients for producers,and organisms/long-term storage.
D)exchange pool/short-term storage,reservoir/long-term storage,and organisms/nutrients available to producers.
E)exchange pool/long-term storage,reservoir/short-term storage,and organisms/nutrients available to producers.

Question 10

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 11

A carbon atom will cycle between an organism and the atmosphere when it is taken up by a producer and is then eaten by an herbivore and eventually passed back into the atmosphere through respiration.The carbon atom has passed through which portions of the nutrient cycle?

A)exchange pool to reservoir to exchange pool to reservoir
B)living organism to long-term storage to living organism to long-term storage
C)living organism to reservoir to living organism to exchange pool
D)living organism to exchange pool to living organism to reservoir
E)living organism to exchange pool to living organism to exchange pool

Question 12

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.

Question 13

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 14

Which of the following organisms would be considered a decomposer?

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

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

Fungi and bacteria are detritus-feeders,also known as

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

Question 17

Deposits of coal are important in the carbon cycle because they

A)keep humans from burning more trees by serving as a fuel source.
B)serve as a reservoir of carbon that will eventually be released into the ecosystem.
C)lock up carbon so that it can never be returned to the atmosphere to make global warming increase.
D)make carbon readily available to plants through their roots growing down into the coal deposit.
E)serve as short-term storage for carbons.

Question 18

Which type of organism produces food in an ecosystem?

A)heterotroph
B)autotroph
C)consumer
D)carnivore
E)herbivore

Question 19

The primary producers in terrestrial ecosystems are the ____,whereas in freshwater and saltwater ecosystems it is ____.

A)autotrophs; heterotrophs
B)herbivore; carnivore
C)consumers; producers
D)algae; green plants
E)green plants; algae

Question 20

The ____ is made of a community of organisms,plus its physical environment.

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

Question 21

Which is NOT a consumer?

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

Question 22

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 23

Which sequence correctly 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 24

In the biosphere,which of the following is NOT constantly recycled?

A)carbon
B)nitrogen
C)water
D)energy
E)phosphorus

Question 25

Ecologists have found that

A)life as we know it does not match the energy laws of physics.
B)ecology cannot be explained using principles from chemistry and physics.
C)it is possible to capture all the photosynthetic energy absorbed in a molecule of glucose.
D)energy flows one way through an ecosystem and requires an external input.
E)inorganic elements flow through an ecosystem.

Question 26

Which eats only plant foods?

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

Question 27

Energy flow in an ecosystem begins with

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

Question 28

Which is NOT true about 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 29

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 30

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 31

Which may be a secondary or tertiary consumer?

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

Question 32

Energy flow in an ecosystem is NOT cyclic because energy is

A)increased as you go up the energy pyramid.
B)evenly spread out over many organisms.
C)converted to many kinds of useful energy.
D)totally destroyed as it is used.
E)no longer useful when it is converted to heat.

Question 33

Most natural food chains are only four or five links long,rarely more.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)This is not correct; most food chains are much longer than four or five links.
E)nutrients cannot be passed after four or five levels.

Question 34

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 35

Compared to the numbers of grasshoppers or deer,there are few mountain lions.The reason that large and fierce animals,such as the mountain lion,are rare in an ecosystem is that

A)such animals do not tolerate other members like them.
B)through evolution,most fierce animals have been killed off by others.
C)food chains are only 10-20% efficient at each step and top carnivores require large amounts of calories for their survival.
D)only a few such animals are permitted by succession in a biome and there are only a few biomes.
E)more large predators bring more disease to an ecosystem.

Question 36

In a grazing food chain,

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

Question 37

The only heterotrophs required for an ecosystem to function are

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

Question 38

Which of the following is NOT necessary to keep a balanced (stable)ecosystem going?

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)Bacteria and fungi should be eliminated.
E)Energy must be allowed to flow through the ecosystem.

Question 39

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 40

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 41

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 42

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 of organisms at each level
D)food chain
E)food web

Question 43

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 44

Less energy is available at the next trophic level because

A)all the food is captured and eaten before it can reach the next trophic level.
B)all of the food eaten is digested and absorbed.
C)only a portion of the food that is digested can be used to make ATP.
D)all of the absorbed food molecules are used as an energy source for ATP buildup in mitochondria.
E)all of the food is absorbed,but not all can be used to make ATP.

Question 45

Inverted ecological pyramids can occur in what habitat?

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

Question 46

Which of the following does NOT add carbon to the atmosphere?

A)photosynthesis
B)burning fossil fuels
C)bicarbonate from aquatic systems
D)carbon dioxide produced by cellular respiration of plants
E)carbon dioxide produced by cellular respiration of animals

Question 47

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 48

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 49

In the following food chain,which organism is at the third trophic level? grass $\rightarrow$ rabbits $\rightarrow$ snakes $\rightarrow$ hawks $\rightarrow$ foxes

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

Question 50

Is the annual productivity of a typical city backyard large enough to support a house cat or will the cat require food supplements in order for it to survive?

A)The producer productivity is large enough for the 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 as part of the producer productivity.
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 51

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 52

Which of the following is NOT true about a food web?

A)It contains many food chains.
B)It contains several trophic levels.
C)It is usually stable.
D)It interacts with the physical environment.
E)It uses only the carbon cycle.

Question 53

Which statement is TRUE about the water (hydrologic)cycle?

A)Because this is a true cycle,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 54

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 55

Fresh water makes up about ____ of the world's supply of water.

A)3 percent
B)10 percent
C)30 percent
D)half
E)90 percent

Question 56

Which of the following is NOT required in robust chemical cycling of inorganic nutrients in a natural ecosystem?

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)plants and animals

Question 57

Someone asks if some of the carbon atoms in their body may have once made up the living tissues of another person or animal in earlier times.This is

A)possible only if you are 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 is always tied up in molecules in organisms or minerals.
E)impossible since carbon molecules are specific for different organisms.

Question 58

When deep wells drain aquifers,it is called

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

Question 59

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 60

How is a carnivore like a 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 use nutrients released from decomposers.

Question 61

Which of the following statements is false regarding the carbon cycle?

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

Question 62

The conversion of nitrate to nitrogen gas is achieved by ____ bacteria.

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

Question 63

The greenhouse effect is

A)due to increased sunlight in recent years.
B)caused by increased plant life and photosynthesis.
C)a natural phenomenon due to absorption of sunlight and re-radiating of the heat.
D)a manmade hazard due to decreased levels of carbon dioxide and ozone in the atmosphere in recent years.
E)not affected by human activities.

Question 64

Which of the following is NOT true of the phosphorus cycle?

A)Phosphorus never enters the atmosphere.
B)Phosphate only becomes available when a geological upheaval exposes sedimentary rocks.
C)Phosphate is often a limiting nutrient in most ecosystems.
D)Phosphate detergents are a major source of eutrophication.
E)The phosphorous cycle is not affected by human activities.

Question 65

Which of the following is NOT a carbon reservoir?

A)living organisms
B)dead organisms
C)coal
D)ammonium and nitrates
E)inorganic carbonate in limestone/carbonaceous shells

Question 66

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 67

Concerning the nitrogen cycle,which of these is NOT true?

A)It requires a number of different types of bacteria.
B)Plants can take in and use nitrogen from the air by using their leaves.
C)Ammonium in the soil is converted to nitrite by nitrite-producing bacteria and then nitrite is converted to nitrate by nitrate-producing bacteria.
D)Eventually,organic nitrogen becomes inorganic nitrogen again.
E)Human activities increase the nitrogen fixation rate.

Question 68

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 69

Atmospheric carbon serves as

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

Question 70

Nitrification refers to the production of

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

Question 71

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

Question 72

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 discover there is a major weed problem in the lake.The most likely cause of the weed problem is

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

Question 73

When an herbivore eats,only about 10 percent of the energy it consumes is available for the next trophic level.Discuss where the remaining 90 percent of the consumed energy goes.

Question 74

The first step in the use of carbon by living organisms occurs in

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

Question 75

Atmospheric CO₂ combines with water to produce a 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 76

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

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