Deck 58: Dynamics of Ecosystems

Question 1

The upper,unconfined portion of the groundwater constitutes the _____,which flows into streams and is partly accessible to plants.

A)aquifer
B)hydrozone
C)water table
D)watershed

Answer 1

C

Question 2

A ____________ cycle is a cyclic path that involves both biological and chemical processes of an ecosystem.

A)biogeochemical
B)complete
C)hydrological
D)complementary

Answer 2

A

Question 3

Except for nitrogen,_________ is the element most likely to be present in amounts so small as to limit the growth of plants.

A)phosphorus
B)potassium
C)sulfur
D)magnesium

Answer 3

A

Question 4

Only about ____ of the sunlight falling on the plant leaves is captured by photosynthesis.

A)1%
B)10%
C)25%
D)50%

Question 5

The balance between photosynthesis and ___________ is altered by the combustion of fossil fuels.

A)respiration
B)sunlight
C)growth
D)decomposition

Question 6

The fraction of Earth's surface covered by oceans is about

A)1/10.
B)1/4.
C)1/3.
D)1/2.
E)3/4.

Question 7

All of the following are true about ecosystems except

A)they contain both living and nonliving components.
B)there is a transfer of energy through the system and it is lost.
C)there is a cycling of nutrients through the system again and again.
D)the ultimate source of energy is the sun for nearly all known ecosystems.
E)they represent the lowest level of biological organization that is known.

Question 8

Which of the following gases in the atmosphere appears to be changing the global climates?

A)ozone
B)water vapor
C)carbon dioxide
D)hydrogen
E)oxygen

Question 9

Heterotrophs must obtain organic molecules that have been synthesized by _____________.

A)biogeochemical cycles
B)bacteria
C)decomposers
D)autotrophs

Question 10

All of the following undergo biogeochemical cycles except

A)carbon.
B)energy.
C)nitrogen.
D)sulfur.
E)water.

Question 11

Over tropical rainforest areas,approximately 90% of the water that reaches the atmosphere comes from

A)animal metabolism.
B)animal perspiration.
C)plant transpiration.
D)plant absorption.
E)plant metabolism.

Question 12

Secondary consumers such as _________ and the parasites of animals,feed on the herbivores.

A)decomposers
B)carnivores
C)herbivores
D)bacteria

Question 13

The carbon cycle is based on carbon dioxide.CO₂ makes up about

A)30% of the atmosphere.
B)3% of the atmosphere.
C)0.3% of the atmosphere.
D)0.03% of the atmosphere.
E)0.003% of the atmospherE.

Question 14

__________ becomes available to organisms almost entirely through the metabolic activities of a few genera of bacteria.

A)Phosphorus
B)Sulfur
C)Nitrogen
D)Iron

Question 15

Photosynthesis fixes about

A)0.1% of the CO₂ present in the atmosphere.
B)1% of the CO₂ present in the atmosphere.
C)10% of the CO₂ present in the atmosphere.
D)20% of the CO₂ present in the atmosphere.
E)almost 100% of the CO₂ present in the atmospherE.

Question 16

Which of the following feed directly on the green plants?

A)primary producers
B)primary consumers
C)secondary consumers
D)secondary producers
E)decomposers

Question 17

The upper,unconfined portion of the groundwater constitutes the

A)aquifer.
B)spring water.
C)surface pool.
D)water table.
E)liquid water.

Question 18

Organisms that break down organic matter are called

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

Question 19

A(n)________ is a permeable underground layer of rock,sand,and gravel saturated with groundwater.

A)natural spring
B)aquifer
C)hot spring
D)submergence

Question 20

______ is defined as the total amount of energy fixed per unit of time minus the amount of energy expended by the metabolic activities of the photosynthetic organisms in the community.

A)Net primary productivity
B)Gross primary productivity
C)Carrying capacity
D)Net metabolism

Question 21

Which of the following biogeochemical cycles contain a mineral component?

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

Question 22

The form of nitrogen most likely to be absorbed from the soil by plants is

A)nitrogenous wastes.
B)nucleic acids.
C)nitrogen gas.
D)nitrous oxide gas.
E)nitrite/nitrate ions.

Question 23

In an ecosystem,which statement reflects the relationship with energy and nutrients?

A)Energy cycles and nutrients also cycle in a balanced ecosystem.
B)Energy flows and nutrients cycle in an ecosystem.
C)Energy cycles and nutrients flow in an ecosystem.
D)Energy flows and nutrients flow through an ecosystem.
E)In an unbalanced ecosystem,nutrients are stored in energy cycles.

Question 24

The net weight of all of the organisms living in an ecosystem is its

A)productivity.
B)biomass.
C)vital force.
D)photosynthesis minus metabolism.
E)combined output of metabolism and photosynthesis.

Question 25

During the 1960s,a group of scientists in the northeastern United States conducted an experiment at Hubbard Brook,New Hampshire.A 38-acre watershed was completely deforested and the runoff (water flow)monitored for several years.It was compared to an adjacent watershed that was left untouched.The scientists collected data during those years and found that

A)there was no difference in the amount of runoff from the two areas.
B)there was a difference but it was not significant,and there was less nitrogen in the runoff from Hubbard Brook than at the control site.
C)there was a tremendous increase in the total amount of runoff but the nitrogen levels were fairly constant in both areas.
D)there was a tremendous increase in the amount of runoff and the nitrogen levels in the runoff were huge compared with the control.
E)there was a tremendous increase in the amount of runoff but the vegetation was able to reestablish itself very quickly and the runoff soon returned to its normal level.

Question 26

Which of the following contain no species that are autotrophs?

A)Bacteria
B)Protista
C)Plants
D)Archaea
E)Fungi

Question 27

Experimental studies with watersheds,such as the one of Hubbard Brook,show that trees and shrubs in an undisturbed ecosystem will help in

A)losing nutrients.
B)retaining the nutrients.
C)secondary productivity.
D)being used as fire wooD.
E)reducing the pollution.

Question 28

The primary consumers are

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

Question 29

With almost no exceptions,the nitrogen fixers are

A)beans.
B)green plants.
C)insects.
D)mammals.
E)prokaryotes.

Question 30

The scarcity of which two elements limits plant growth?

A)oxygen,nitrogen
B)nitrogen,phosphorus
C)oxygen,phosphorus
D)carbon,nitrogen
E)carbon,phosphorus

Question 31

A good average value for the amount of organic matter that reaches the next trophic level is about

A)20%.
B)10%.
C)5%.
D)2%.
E)1%.

Question 32

Factors that could determine productivity of an aquatic community include all of the following except

A)nitrogen-fixing bacteriA.
B)seasonality.
C)the number of autotrophs.
D)a limiting nutrient.
E)rainfall.

Question 33

In global terms,the production of CO₂ by respiration and its fixation by photosynthesis are balanced,but the balance has been shifted towards accumulation of CO₂ by the increase in use of

A)meat products.
B)vegetable products.
C)fossil fuels.
D)all types of foods.
E)nuclear energy.

Question 34

The organisms that live on the refuse of an ecosystem are called

A)autotrophs.
B)carnivores.
C)denitrifiers.
D)detritivores.
E)herbivores.

Question 35

Organisms depend on nutrient cycling.Nutrient cycling involves all of the following processes except

A)respiration.
B)photosynthesis.
C)decomposition.
D)feeding.
E)heat radiation.

Question 36

Which of the following choices best describes the relationship that exists between photosynthesis and cellular respiration?

A)Photosynthesis captures and stores carbon from the atmosphere.Cellular respiration releases carbon back into the atmosphere.
B)Photosynthesis captures and stores carbon from the atmosphere as does cellular respiration.
C)Photosynthesis releases carbon into the atmosphere.Cellular respiration captures and stores carbon from the atmosphere.
D)Photosynthesis releases carbon into the atmosphere as does cellular respiration.

Question 37

Energy enters the ecosystem mainly by the process of

A)biosynthesis.
B)nutrition.
C)biogeochemical weathering.
D)photosynthesis.
E)metabolism.

Question 38

Even though nitrogen constitutes 78% of Earth's atmosphere,the amount available for living things nearly all comes from

A)a few groups of nitrogen-fixing bacteriA.
B)the breakdown of minerals.
C)a few genera of detritivores.
D)the breakdown of dead plants.
E)nitrogen-containing fertilizers.

Question 39

In an ecosystem,the amount of organic matter produced in a given time that is available for heterotrophs is known as

A)daily yield.
B)gross productivity.
C)net primary productivity.
D)effective vitality.
E)net yield.

Question 40

The rate of production of new biomass by heterotrophs is called

A)secondary productivity.
B)primary productivity.
C)consumer productivity.
D)gross productivity.
E)net productivity.

Question 41

Which one of the links in the food chain shown below does the garden spider represent?
Grass-cricket-garden spider-blue jay-red-tailed hawk

A)producer
B)primary producer
C)primary consumer
D)secondary consumer
E)tertiary consumer

Question 42

In a food chain with four trophic levels,what would be the energy in the top trophic level if the energy contained in the primary producer level is 40,000 kcal/m²/yr? Assume a trophic level transfer efficiency of 10%.

A)4,000 kcal/m²/yr
B)400 kcal/m²/yr
C)40 kcal/m²/yr
D)4 kcal/m²/yr
E)0.4 kcal/m²/yr

Question 43

Which one of the links in the food chain shown below is the producer?
Grass-cricket-garden spider-blue jay-red-tailed hawk

A)grass
B)cricket
C)garden spider
D)blue jay
E)red-tailed hawk

Question 44

What feature do the carbon and nitrogen cycles have in common?

A)a large atmospheric component
B)involvement in global climate change
C)often a limiting nutrient
D)mostly local cycling
E)many microbes involved in cycling

Question 45

Which one of the following cycles is characterized by often being a limiting nutrient in ecosystems and having no atmospheric component in its cycle?

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

Question 46

A Viceroy caterpillar feeds on a leaf.If a day's feeding gains the caterpillar a total of 1000 calories and 50% is lost in its feces and 33% of the energy is used through cellular respiration,how many calories of the original intake are available for caterpillar biomass?

A)830 calories
B)670 calories
C)500 calories
D)330 calories
E)170 calories

Question 47

Which of the following terms could be used by you as you explain to your teacher your understanding of the total amount of organic matter produced in a community in a given time that is available for heterotroph consumption?

A)primary productivity
B)secondary productivity
C)primary production
D)net primary production
E)net secondary production

Question 48

Which one of the following quantities best represents the respiratory heat lost by plants in an ecosystem?

A)gross primary productivity
B)net primary productivity
C)gross primary productivity - net primary productivity
D)gross primary productivity - standing crop biomass
E)gross primary productivity - secondary productivity

Question 49

Which one of the following explanations for why the tropics have greater species diversity than the temperate zone is least convincing?

A)Seasonality variability is less in the tropics.
B)Niches are narrower in the tropics.
C)Fewer predators in the tropics allow more prey species to flourish.
D)Greater spatial heterogeneity in the tropics creates more niches.
E)The tropics have greater plant production,which supports greater overall species richness.

Question 50

Which one of the following ecosystems is most likely to show an inverted biomass pyramid but a normal energy pyramid?

A)grassland
B)open ocean
C)intertidal
D)tropical forest
E)desert

Question 51

In a marine ecosystem with an inverted biomass pyramid,which trophic level should have the smallest number of organisms?

A)phytoplankton
B)zooplankton
C)primary carnivores (sardines)
D)secondary carnivores (tuna)
E)detritivores

Question 52

The following figure shows studies in a stream where enclosures were setup either with trout or with no trout.Which statement is a correct interpretation of the graph about trout,invertebrates,and algae?

A)If trout are present in a system,alga production is low and invertebrate population levels are also low.
B)If trout are present in a system,alga production is high and invertebrate population levels are also high.
C)If trout are present in a system,alga production is high and invertebrate population levels are low.
D)Trout do not seem to affect the alga production;only the invertebrate populations are affecteD.
E)Trout do affect the alga production but not the invertebrate populations.

Question 53

Addition of a primary carnivore to an ecosystem can sometimes influence the whole ecosystem.This process is called

A)a top-down effect.
B)a bottom-up effect.
C)species turnover.
D)disruption.
E)a trophic cascadE.

Question 54

In a food chain consisting of four trophic levels,if the energy present in the top level is 48 kcal/m²/yr,how much energy do you expect in primary consumers? (Use an energy transfer rate of 10%. )

A)4.8 kcal/m²/yr
B)48 kcal/m²/yr
C)480 kcal/m²/yr
D)4,800 kcal/m²/yr
E)48,000 kcal/m²/yr

Question 55

According to MacArthur and Wilson's island biogeography theory,which of the following would be expected to have the smallest species diversity?

A)the mainland
B)a large island near the mainland
C)a large island far from the mainland
D)a small island near the mainland
E)a small island far from the mainland

Question 56

Which one of the following statements about the carbon cycle is false?

A)Carbon and nitrogen fixation have analogous functions in their cycles.
B)Burning of fossil fuels has lead to the current imbalance in the carbon cycle.
C)Cutting down rainforests decreases atmospheric CO₂ levels.
D)In water,inorganic carbon exists in two different forms,both of which can be used by autotrophs.
E)Carbon cycles globally.

Question 57

What feature do the carbon and phosphorus cycles have in common?

A)involvement in acid rain
B)large mineral deposits
C)involvement in eutrophication
D)large atmospheric component
E)often a limiting nutrient

Question 58

In a pond ecosystem,a crayfish feeds on three species of algae.It in turn is preyed on by one species of fish and a heron.The heron also preys upon the fish.What is the minimum number of food chains in this food web?

A)2
B)3
C)4
D)5
E)6

Question 59

Which one of the links in the food chain shown below does the cricket represent?
Grass-cricket-garden spider-blue jay-red-tailed hawk

A)producer
B)primary producer
C)primary consumer
D)secondary consumer
E)tertiary consumer

Question 60

Which one of the following observations was not an outcome of studies by David Tilman and coworkers at Cedar Creek,Minnesota on ecosystem stability?

A)Plots with more species showed less year-to-year variation in biomass.
B)Species rich plots were less affected by drought than species poor plots.
C)More diverse plots were less susceptible to invasion by new species.
D)Nitrogen uptake and total biomass produced were negatively correlated to species richness.
E)Overyielding was observed in more recent work at Cedar Creek.

Question 61

Which one of the following observations is not an expected outcome from the bottom-up model for trophic-level interactions?

A)When primary production is low,biomass of herbivores and carnivores are also low.
B)When primary production increases above the low level,the herbivore biomass also increases.
C)When primary production increases above the low level,the carnivore biomass also increases.
D)As primary production increased further,the carnivore biomass continued to increase.
E)The herbivore biomass remained fairly independent of primary production at higher production levels.

Question 62

Choose the letter of the best match from the following:
A.ecological pyramid of energy
B.ecosystem
C.species diversity cline
D.food web/food chain
E.biogeochemical cycles
Organisms that feed on one another;include producers,consumers,detritivores;the length and complexity of the chain of these organisms vary.

Question 63

In an aquatic ecosystem,a secondary carnivore is temporarily excluded and then,after a period of time,is returned.Which one of the following is not an expected top-down effect after it is returned?

A)Primary carnivores become less abundant.
B)Primary productivity increases.
C)Algae decrease.
D)Herbivores become more abundant.
E)Secondary carnivore biomass increases.

Question 64

Choose the letter of the best match from the following:
A.ecological pyramid of energy
B.ecosystem
C.species diversity cline
D.food web/food chain
E.biogeochemical cycles
All of the organisms that live in a place,together with the physical characteristics of the place;they interact with each other in a dynamic fashion.

Question 65

Choose the letter of the best match from the following:
A.ecological pyramid of energy
B.ecosystem
C.species diversity cline
D.food web/food chain
E.biogeochemical cycles
Organisms are interrelated;energy transfers through the various trophic levels;there are a low number of herbivores,which are supported by much larger numbers of photosynthesizers.

Question 66

Choose the letter of the best match from the following:
A.ecological pyramid of energy
B.ecosystem
C.species diversity cline
D.food web/food chain
E.biogeochemical cycles
Cyclic paths involving both biological and chemical processes.Begin with chemicals being incorporated into the bodies of organisms from nonliving reservoirs such as atmosphere or the waters of oceans or rivers or rocks.

Question 67

Choose the letter of the best match from the following:
A.ecological pyramid of energy
B.ecosystem
C.species diversity cline
D.food web/food chain
E.biogeochemical cycles
A latitudinal increase in the number of species;ranges from the Arctic,increasing toward equatorial tropical areas.

Question 68

Which one of the following statements about the trophic cascade in the sea otter and sea urchin-kelp communities along the West Coast of North America is false?

A)Increased sea otter populations are linked to more profuse growth of the kelp forests.
B)Increased sea otter populations are linked to reduced sea urchin populations.
C)Increased orca (killer whale)predation on sea otters is linked to more profuse growth of the kelp forests.
D)Increased orca (killer whale)predation on sea otters is linked to increased sea urchin populations.
E)Increased sea urchin populations are linked to less profuse growth of the kelp forests.

Question 69

All of the following factors except one affect species richness.Select the exception.

A)loss of keystone species
B)moderate physical disturbance
C)primary productivity
D)habitat heterogeneity
E)species diversity cline