Deck 37: Ecosystems

Question 1

The figure below shows the net primary productivity (NPP) in terrestrial and marine biomes around the world.
The pattern of NPP in marine ecosystems as shown above suggests that

A) marine productivity is as sensitive to temperature as terrestrial productivity.
B) without shade from overhead vegetation, marine productivity typically exceeds that found in terrestrial ecosystems.
C) marine ecosystems are also limited by sunlight, with the highest productivity at the equator.
D) most marine productivity results from the input of terrestrially derived nutrients.

Answer 1

D

Question 2

Geologists suspect a large asteroid struck the Earth 65 million years ago. What are the most probable ecological consequences from such an impact?

A) The asteroid's impact would have altered the tilt of the Earth and the timing of the seasons, resulting in extensive failures in plant reproduction.
B) Lifeforms transported by the asteroid would have caused disruptions to the evolution of life on Earth.
C) The ash cloud created by the impact would have magnified the greenhouse effect at least a thousandfold, causing massive goal warming.
D) The ash cloud created by the impact would have reduced solar radiation to the extent that photosynthesis was no longer possible.

Answer 2

D

Question 3

Almost all life on Earth is directly or indirectly dependent on

A) predation
B) solar energy.
C) physical productivity.
D) human civilization.

Answer 3

B

Question 4

Which of the following series best represents the energy flow in an ecosystem?

A) sun ® consumer ® producer ® heat
B) consumer ® producer ® decomposer ® sun
C) consumer ® producer ® decomposer ® sun
D) sun ® producer ® consumer ® heat

Question 5

Which of the following is the dominant type of organism in the two natural terrestrial ecosystems that have the greatest net primary productivity (NPP)?

A) grass
B) trees
C) food crops
D) fish

Question 6

Which of the following describes the ultimate disposition of most energy in an ecosystem?

A) It is used to construct the bodies of decomposers.
B) It is trapped as fossil fuels when producers die and become fossilized.
C) It is continuously recycled back into the ecosystem.
D) It eventually returns to space in the form of heat.

Question 7

In an ecosystem energy differs from nutrients in that

A) energy is recycled through photosynthesis but nutrients are recycled through the atmosphere.
B) nutrients are recycled but energy eventually moves out of the system and is lost.
C) nutrients are recycled through plant roots but energy is recycled through leaves.
D) energy is recycled by producers but nutrients are recycled by consumers.

Question 8

Other than the polar tundra, the least productive biomes tend to be

A) deserts.
B) the temperate forests.
C) the tropical forests.
D) estuaries.

Question 9

In marine ecosystems, net primary productivity tends to

A) be greater along shorelines where terrestrial nutrients enter the marine environment.
B) be lower where the oceans border land because terrestrial pollution suppresses marine productivity.
C) be lowest in areas where upwelling brings colder water to the surface.
D) be greater than the net primary productivity on land.

Question 10

Which of the following would utilize the highest percentage of net primary productivity?

A) producers
B) decomposers
C) herbivores
D) predators

Question 11

The energy in sunlight is directly associated with the synthesis of

A) carbon dioxide.
B) sugars.
C) fats.
D) nucleic acids.

Question 12

Which of the following statements about cycling within an ecosystem is false?

A) Energy is recycled within an ecosystem.
B) Carbon is recycled within an ecosystem.
C) The sedimentary nutrient cycle cycles nutrients very slowly.
D) Human activities affect nutrient cycling.

Question 13

Which of the following groups of organisms would not be considered to be consumers?

A) herbivores
B) predators
C) photosynthesizers
D) decomposers

Question 14

Net primary productivity in a terrarium could be estimated by

A) carefully controlling the amount of light entering it.
B) counting the change in the number of plant species in it.
C) weighing the terrarium at regular intervals.
D) removing the primary consumers and weighing them at regular intervals.

Question 15

The rate of new biomass production by consumers is called

A) primary productivity.
B) a biomass flow chain.
C) an energy pyramid.
D) secondary productivity.

Question 16

On average, what percentage of the energy from one trophic level of an energy pyramid is transferred to the next trophic level?

A) 10
B) 33
C) 50
D) 100

Question 17

What best explains the low productivity of the open ocean?

A) The open ocean lacks insufficient light to support photosynthesis.
B) Nutrients rapidly sink to depths that sunlight can not reach.
C) The open ocean is actually very productive but its primary producers are consumed as quickly as they grow.
D) These regions are typically too cool to support significant primary production.

Question 18

A spacecraft crash lands on an airless, lifeless moon. All that survives, along with the crew, are some chickens, corn flakes, and vitamins. The air and water recyclers are functioning. To maximize their food supply until rescued the crew should

A) feed the corn flakes and vitamins to the chickens, then eat the eggs until rescued.
B) kill all the chickens immediately, eat them first, then eat the corn flakes.
C) mark each week's survival by eating one chicken
D) ration the chickens first, when they are all eaten shift to the corn flakes

Question 19

The marine ecosystem with the lowest net primary productivity is

A) the coral reef.
B) the open ocean.
C) swamp and marsh areas.
D) the ocean upwelling zone.

Question 20

Cougars defend a relatively large territory; consider the following facts and estimate how much area a cougar would require: A cougar requires 490 kg annually and obtains most of its food from deer, which average 55 kg. In typical deer habitat the NPP is 35 kg per acre. One deer consumes approximately 1,150 kg of vegetation each year.

A) 300 acres
B) 1,925 acres
C) 3,000 acres
D) 4,500 acres

Question 21

Human activities

A) rarely affect nutrient cycles.
B) can alter nutrient cycles on a global scale.
C) tend to cause only local changes in nutrient cycles.
D) generally improve nutrient cycling in ecosystems.

Question 22

The figure below illustrates how nutrients cycle between organic and inorganic reservoirs. Within each reservoir the nutrient may be available or unavailable for use.
According to the figure above, what is the inorganic reservoir where phosphorus is unavailable?

A) the atmosphere
B) the soil
C) ocean sediments
D) decomposers

Question 23

Sedimentary nutrients

A) cycle very slowly and can often become limiting.
B) are easily replaced if lost from an ecosystem by erosion of the local rock.
C) are distributed from locally abundant reservoirs through atmospheric circulation.
D) include carbon, oxygen, nitrogen, and sulfur.

Question 24

In the absence of _____, nutrient recycling within the ecosystem would completely stop.

A) rocks
B) secondary consumers
C) decomposers
D) predators

Question 25

Within the ecosystem, nutrients

A) move in a one-way path from producers toward consumers.
B) regularly cycle between organisms and the nonliving environment.
C) are consumed by their use and thus not available for recycling.
D) are rarely limiting because they are constantly replenished as the Earth's crust is eroded.

Question 26

With respect to the following values, rain with a pH of _____ would be the most acidic.

A) 7
B) 3
C) 8
D) 5

Question 27

To best utilize the earth's NPP to feed the most people, diets should be modified to include _______ and gathering the maximum amount of energy available from a given biomass of producers.

A) only meat, moving higher up the food chain,
B) only meat, moving lower down the food chain,
C) plant material only, moving lower down the food chain,
D) plant material only, moving higher up the food chain,

Question 28

What best explains this observation: consumers directly use approximately 20 percent of a forest's net primary productivity (NPP) while decomposers directly use approximately 80?

A) Decomposers are more efficient at obtaining energy than consumers.
B) Forest ecosystems do not have a very high NPP, so they cannot support as many consumers as other ecosystems can.
C) Consumers eat only certain parts of organisms, such as fruits or muscle tissue, while decomposers obtain energy from the entire body of the food organism.
D) Secondary consumers eat the primary consumers more quickly than the primary consumers can eat the producers, thus leaving most of the NPP available to the decomposers.

Question 29

Over time the total amount of nutrients such as carbon and iron present on the earth increases by their addition from

A) meteoric matter from space.
B) volcanic activity.
C) nutrient recycling.
D) electromagnetic radiation.

Question 30

Cutting a forest to produce paper bags that are quickly discarded could be considered shortsighted; with the majority of its trees removed the forest will

A) experience a significant loss of nutrients as they leech through the soil and into nearby waterways.
B) not be unable to recover and will eventually be replace with a desert.
C) no longer be able to recycle the energy it captures during photosynthesis.
D) all of the above

Question 31

Secondary productivity can never exceed primary productivity, because

A) secondary productivity is limited by the amount of energy produced by primary producers.
B) secondary productivity is less efficient than primary productivity.
C) energy loss to the surroundings in an ecosystem depends mostly on tertiary consumers.
D) nutrient cycling is much slower in secondary productivity.

Question 32

The primary contribution of decomposers to an ecosystem occurs when they

A) capture solar energy.
B) recycle nutrients sequestered in organisms back to the physical environment.
C) regulate the number of producers.
D) prevent consumers overpopulation.

Question 33

Pollutants from industrial areas may contain _______, which can react with water to produce airborne particles of acid.

A) oxygen
B) carbon dioxide
C) sulfur dioxide
D) nitrate

Question 34

Which of the following statements best describes the impact of human activities on the cycling of nutrients in natural systems?

A) Human activities are essentially benign and have little lasting impact on either atmospheric or sedimentary nutrient cycling.
B) Human activities have profoundly impacted nutrient cycling, particularly with those nutrients that cycle within the atmosphere.
C) Human activities like mining, construction, and road building disrupt the Earth's surface and greatly increase those nutrients with sedimentary cycling pathways.
D) Human activities in general significantly enhance nutrient availability and are almost always associated with ecosystem improvements.

Question 35

Which of the following would most likely take longest to replace if lost from a terrestrial ecosystem?

A) sulfur
B) carbon
C) oxygen
D) phosphorous

Question 36

The dead zone that develops in the Gulf of Mexico forms because the large amounts of nitrogen from fertilizers and sewage carried by the Mississippi River

A) kill the algae, which are the main food of primary consumers.
B) cause bacterial populations to grow rapidly and create widespread disease among secondary consumers.
C) lead eventually to large bacterial populations that deplete deeper waters of oxygen.
D) are poisonous to bacteria, which are critically important decomposers.

Question 37

Once an organic molecule enters a metabolic pathway a significant percentage of its energy

A) can be recycled through the ecosystem.
B) will be recovered and used by decomposers.
C) is lost as unrecoverable heat.
D) enters the nutrient cycle.

Question 38

Nutrients that have an atmospheric cycle

A) include carbon, nitrogen, and phosphorus.
B) may be affected by events that occur in distant parts of the globe.
C) may become trapped in ocean sediments until tectonic processes elevate the ocean floor.
D) can quickly become locally depleted and limit NPP.

Question 39

The impacts of acid rain

A) are quickly reversed by most soils.
B) can last for long periods of time.
C) are almost entirely confined to terrestrial ecosystems.
D) presently are experienced only in the United States.

Question 40

The rate of secondary productivity is highest in areas

A) with low net primary productivity.
B) with few producers.
C) with high net primary productivity.
D) where plants act as decomposers.

Question 41

Rainfall with a low pH is called _______.

Question 42

A nutrient whose biogeochemical cycle does not include a atmospheric phase is said to have a(n) _______ cycle.

Question 43

Ecosystems are closed systems.

Question 44

All areas of the same landmass have the same net primary productivity.

Question 45

The term ecosystem services is used to describe beneficial activities performed by healthy ecosystems, some examples include

A) pollination of crops
B) flood control
C) filtering of pollutants from water
D) all of the above

Question 46

Coral reefs and swamps are among Earth's most productive ecosystems.

Question 47

In an ecosystem the assemblage of living organisms constitutes the _____ component.

Question 48

Biologists use the term _______ to refer to the weight of organisms per unit area.

Question 49

Nutrients that have a(n) _______ cycle move relatively quickly through terrestrial and aquatic ecosystems.

Question 50

Biosphere II demonstrated that

A) living without the contribution of natural ecosystems is less complex than originally thought.
B) building a self-sustaining model of a biosphere is not yet possible.
C) the environmental factors are much less significant than the social and psychological factors when human are confined.
D) a self-sustaining moon colony will probably exist within two generations.

Question 51

Some biologically important substances are transferred between organisms and the physical environment in a cyclical pattern called a ________ cycle.

Question 52

In marine ecosystems the highest concentrations of persistent organic pollutants (POPs) will be found

A) in the bottom sediments where the remains of dead organisms eventually accumulate.
B) in the bodies of tertiary and quaternary consumers which represent the transfer of the energy and nutrients from the lower trophic levels.
C) in the water since POPs are recycled by decomposers just like any other nutrient.
D) in marine producers because they form the base of marine food webs and are the most numerous type of organisms.

Question 53

Eventually, all biomass produced by any organism is consumed by _______.

Question 54

The rate of new biomass production by consumers is called _________ production.

Question 55

Phosphorus is the only major nutrient whose cycle is _____.

Question 56

Human actions such as logging, building on a floodplain, or diverting rivers increases the probability of severe _______.

Question 57

In the Hubbard Brook Experimental Forest in New Hampshire, a portion of the forest was first clear-cut, then sprayed with herbicides for 3 years to prevent growth. A second portion of the forest was not clear-cut or sprayed and served as a control plot. The graph below shows that nitrate, a form of nitrogen that is important to plants, was lost from the ecosystem in streams at a much higher rate in the clear-cut portion of the forest than in the control portion.
What best explains the small releases of nitrogen from the control portion of the forest at the Hubbarb Brook Experimental Forest?

A) Its nitrogen was sequestered in the forest biomass and temporarily unavailable.
B) With intact vegetation to intercept the acid rain that falls in the area it failed to reach the soil and chemically react to release the nitrogen.
C) With intact vegetation, rainwater washed little soil and nitrogen from the forest floor.
D) All of the above contributed to the small amount of nitrogen loss.

Question 58

A community of organisms together with the chemical and physical environment in which the organisms live is known as a(n) _______.

Question 59

The amount of energy that organisms capture in photosynthesis, minus the amount lost as heat from respiration, is called ___ _______ ___________.

Question 60

Each level of an energy pyramid corresponds to a step in a food chain and is called a _______ level.

Question 61

Energy cannot be recycled.

Question 62

An atom of phosphorous may remain out of the biological part of its cycle for many millions of years.

Question 63

Rainfall in some areas of Canada has a high acidity level and a correspondingly high pH.

Question 64

Primary consumers harvest nearly 100 percent of the energy that producers capture from the sun.

Question 65

Approximately 100 percent of the energy captured from the sun is passed from trophic level to trophic level.

Question 66

Most human-caused environmental damage can be successfully reversed and natural habitats can be reconstructed.

Question 67

Essential elements required by producers are called nutrients.

Question 68

Rainfall naturally has a neutral pH.