Deck 54: Ecosystems

Question 1

An available nutrient molecule ____.

A) exists in living or dead tissues
B) cannot be assimilated by organisms
C) can be assimilated by organisms
D) exists in rocks and soil
E) exists as an ion

Answer 1

C

Question 2

The rate at which producers convert solar energy into chemical energy is an ecosystem's ____.

A) standing crop biomass
B) biogeochemical cycle
C) net primary productivity
D) efficiency
E) gross primary productivity

Answer 2

E

Question 3

Net primary productivity is a measure of the rate at which ____ accumulate energy, as well as the rate at which new ____ is added to a system.

A) consumers; inorganic material
B) producers; inorganic material
C) carnivores; prey
D) producers; biomass
E) consumers; biomass

Answer 3

D

Question 4

Geographically, where is net primary productivity the highest?

A) at the north pole
B) at the south pole
C) between 30^oand 60^o
D) in the Northern hemisphere
E) at the equator

Question 5

How much solar energy is ultimately converted into chemical energy by photosynthesis?

A) less than 1%
B) 1-2%
C) 5%
D) 10%
E) 20%

Question 6

Which factors govern the rate of primary productivity in freshwater and marine ecosystems?

A) availability of water
B) availability of sunlight and nutrients only
C) depth of the water only
D) depth of the water and availability of sunlight and nutrients
E) availability of oxygen

Question 7

High ____ concentrations in Lake Erie encouraged the growth of photosynthetic algae, which changed the phytoplankton community.

A) sewage
B) detergent
C) coliform bacteria
D) phosphorous
E) dead fish

Question 8

Which class of organisms makes up the detrital food web?

A) carnivores and decomposers
B) decomposers and detritivores
C) decomposers and producers
D) herbivores and carnivores
E) producers and herbivores

Question 9

The overall ecological efficiency of most organisms is between ____ percent.

A) 1 and 2
B) 2 and 5
C) 5 and 20
D) 10 and 50
E) 50 and 75

Question 10

Geological processes in the nutrient cycle operate ____.

A) quickly
B) slowly
C) on living material
D) only on organic matter
E) on solar energy

Question 11

About how much solar energy is intercepted by Earth every minute?

A) 9 kcal per square meter
B) 19 kcal per square meter
C) 190 kcal per square meter
D) 19 kcal per square kilometer
E) 190 kcal per square kilometer

Question 12

A non-native species accidentally introduced into Lake Erie, ____ inadvertently helped restore the polluted lake by eating phytoplankton.

A) mayflies
B) oligochaete worms
C) phytoplankton
D) salmon
E) zebra mussels

Question 13

Which ecosystem covers a large percentage of Earth's surface and, despite having low productivity, contributes a high percentage of total net primary productivity?

A) open ocean
B) extreme desert, rock, sand, ice
C) desert and thornwoods
D) tropical deciduous forest
E) temperate rainforest

Question 14

Ecologists use compartment models to describe ____.

A) grazer food webs
B) detrital food webs
C) nutrient cycling
D) species richness
E) inputs of solar energy

Question 15

Herbivores are ____ energy transfer(s) away from the sun.

A) one
B) two
C) three
D) four
E) five

Question 16

Biogeochemical cycles describe ____.

A) the constant recycling of nutrients between biotic and abiotic components of ecosystems
B) pathways by which energy and nutrients move through biotic components of ecosystems
C) all available nutrients in an ecosystem
D) a series of mathematical equations that define an ecosystem's most important relationships
E) the input of solar energy into a closed ecosystem

Question 17

Respiration affects a compartment model by ____.

A) moving carbon, but not oxygen, from the available organic compartment to the available inorganic component
B) moving oxygen, but not carbon, from the available organic compartment to the available inorganic component
C) moving both carbon and oxygen from the available organic compartment to the available inorganic component
D) moving both carbon and oxygen from the available inorganic compartment to the available organic component
E) moving carbon, but not oxygen, from the available inorganic compartment to the available organic component

Question 18

The Lake Erie ecosystem was affected by humans because human activities ____.

A) extracted resources without replacement
B) caused global warming
C) used the water without replacement
D) disrupted energy flow and the cycling of nutrients
E) extracted energy without replacement

Question 19

One disadvantage of a simulation model of an ecosystem is that it ____.

A) does not take into effect interactions between organisms
B) does not take into effect nutrient availability
C) does not take into effect water availability
D) may not be accurate
E) may predict disastrous consequences

Question 20

Sedimentation converts ions and particles from the ____ into rocks of the ____.

A) available inorganic compartment; unavailable inorganic compartment
B) unavailable inorganic compartment; unavailable organic compartment
C) available inorganic compartment; available organic compartment
D) available inorganic compartment; unavailable organic compartment
E) available organic compartment; unavailable inorganic compartment

Question 21

How do the pyramids of biomass for Silver Springs, Florida, and the English Channel compare?

A) They are both typical of most ecosystems.
B) They both indicate that producers are quickly eaten by herbivores.
C) The pyramid for Silver Springs is typical of most ecosystems, and the English Channel pyramid indicates that producers are quickly eaten by herbivores.
D) The pyramid for Silver Springs indicates that producers are quickly eaten by herbivores, and the English Channel pyramid is typical of most ecosystems.
E) Both pyramids indicate overgrowth of producers.

Question 22

Which three factors determine the ecological efficiencies of consumers?

A) assimilation and harvesting efficiencies, and nutrient volume
B) assimilation and harvesting efficiencies, and water volume
C) production, harvesting, and assimilation efficiencies
D) production and harvesting efficiencies, and amount of sunlight
E) production and harvesting efficiencies, and percentage of decomposers

Question 23

Assimilation efficiency is the ratio of ____.

A) energy content of food consumed to the energy content of food available
B) energy absorbed from consumed food to the food's total energy content
C) energy content of new tissue produced to the energy assimilated from food
D) net productivity at one trophic level to the trophic level below
E) producers to consumers

Question 24

Biological magnification is best defined as ____.

A) the increase in toxicity of a chemical compound resulting from its metabolism by a living organism
B) the higher relative proportion of biomass among producers as compared to consumers in an ecosystem
C) the concentration of nondegradable poisons within organisms at higher trophic levels
D) the concentration of degradable poisons within organisms at lower trophic levels
E) the declining relative proportion of nondegradable poisons in organisms at higher trophic levels as compared to those at lower trophic levels

Question 25

Endothermic animals use the majority of their energy to _____.

A) digest
B) grow
C) move
D) reproduce
E) stay warm

Question 26

Trophic pyramids typically have a ____ base and a ____ top portion.

A) narrow; narrow
B) narrow; wide
C) wide; narrow
D) wide; wide
E) flat; flat

Question 27

Which organisms would most likely have the highest tissue concentration of DDT?

A) zooplankton
B) small herbivorous fish
C) large predatory fish
D) osprey
E) large herbivorous fish

Question 28

Why is a pyramid of numbers for a forest sometimes narrow at the bottom?

A) Energy decreases as it passes through each trophic level.
B) Energy increases as it passes through each trophic level.
C) Individual producers are small and very numerous.
D) Herbivorous insects vastly outnumber large producers.
E) Large producers vastly outnumber insects.

Question 29

Nearly all ecosystems receive a constant input of energy from ____.

A) bacteria
B) biomass
C) nutrients
D) plants
E) the sun

Question 30

A ____ restricts productivity.

A) primary producer
B) secondary producer
C) photosynthesizer
D) detritivore
E) limiting nutrient

Question 31

Which marine ecosystem has the highest mean net primary productivity?

A) continental shelf
B) estuaries
C) kelp beds and reefs
D) open ocean
E) upwelling zones

Question 32

Compared to other regions, day length is ____ and sunlight intensity is ____ near the equator.

A) least variable; strongest
B) least variable; weakest
C) more variable; strongest
D) more variable; weakest
E) least variable; constant

Question 33

What is the ratio of the energy content of food consumed to the energy content of food available?

A) ecological efficiency
B) harvesting efficiency
C) production efficiency
D) assimilation efficiency
E) net primary productivity

Question 34

Why should humans consider eating "lower on the food chain"?

A) We digest and assimilate plant material more efficiently than meat.
B) We digest and assimilate meat more efficiently than plant material.
C) Many regions exist that support vegetation suitable only for feeding large herbivores.
D) Energy efficiency is greater when passed through fewer trophic levels.
E) No biological reaction is 100% efficient.

Question 35

The analysis of energy flow in an aquatic ecosystem in Silver Springs, Florida, revealed that ____.

A) energy flows are difficult to measure
B) most of the sun's energy is harvested
C) only a little energy is transferred from one trophic level to the next
D) the energy flow in carnivores is equal to that of producers
E) trophic energy losses are not significant

Question 36

Zooplankton eating phytoplankton almost as soon as they appear in marine ecosystems causes the pyramid of biomass to ____.

A) resemble the pyramid of energy
B) invert
C) widen at the base
D) add trophic levels
E) to become obsolete

Question 37

Which ecosystem has the lowest percentage of total net primary productivity?

A) open ocean
B) savanna
C) swamp and march
D) temperate deciduous forests
E) tundra

Question 38

The standing crop biomass is the ____.

A) amount of sunlight absorbed by the plants
B) amount of water accumulated per acre of crop plants
C) total dry weight of plants at a given time
D) number of plant species present
E) productivity of the plants

Question 39

Which factors besides sunlight influence the rate of primary productivity?

A) temperature and total number of organisms
B) photosynthesis and availability of nutrients
C) temperature and availability of water
D) photosynthesis and availability of water
E) temperature and photosynthesis

Question 40

Salt marsh cordgrass is consumed by herbivorous marsh periwinkle snails, which in turn are consumed by blue crabs. Research has shown that cordgrass productivity is controlled ____.

A) indirectly by the abundance of snails
B) indirectly by the abundance of snail predators
C) directly by the abundance of snail predators
D) directly by the availability of nutrients in the salt marsh
E) indirectly by the amount of sunlight penetrating the water

Question 41

The products of ____ are N₂O and N₂.

A) ammonification
B) biological magnification
C) denitrification
D) nitrification
E) nitrogen fixation

Question 42

Earth is essentially a closed system with respect to ____.

A) energy
B) matter
C) oxygen
D) photosynthesis
E) ecosystems

Question 43

Nitrogen is made available to plants for their use by the process(es) of ____.

A) ammonification only
B) nitrification only
C) nitrogen fixation only
D) ammonification and nitrification only
E) ammonification, nitrification, and nitrogen fixation

Question 44

The main natural source of phosphorus is ____.

A) Earth's crust
B) fertilizer
C) guano
D) legumes
E) water

Question 45

The Hubbard Brook Watershed Project illustrated that ____.

A) deforestation increases nutrients in nearby aquatic ecosystems
B) deforestation can result in polluted streams
C) deforestation results in calcium retention in soil
D) primary consumers are the most important part of that energy pyramid
E) trees absorb too much water and are not useful in a watershed area

Question 46

Which carbon reservoir contains the most carbon?

A) atmosphere
B) biomass on land
C) lakes
D) oceans
E) soil

Question 47

Anthropogenic events ____.

A) refer to the carbon cycle
B) refer to all nutrient cycles
C) originate with human activities
D) refer to absorption of the sun's energy in the atmosphere
E) are caused by human overpopulation

Question 48

Experiments in which nitrogen supplementation increased the biomass of both plants and herbivores show ____.

A) bottom-up control
B) top-down control
C) indirect control
D) inverted cascades
E) nutrient cycling

Question 49

The largest reservoir of phosphorus is the ____.

A) oceans
B) polar ice and glaciers
C) rocks
D) lakes and rivers
E) atmosphere

Question 50

The largest reservoir of carbon is ____.

A) consumers
B) nutrients in soil
C) producers
D) sedimentary rock
E) water

Question 51

In the hydrologic cycle, water moves from the land to the air by ____ and returns to the land via ____.

A) precipitation; evaporation and transpiration
B) precipitation and evaporation; transpiration
C) precipitation and transpiration; evaporation
D) transpiration; precipitation and evaporation
E) transpiration and evaporation; precipitation

Question 52

Greenhouse gases include ____.

A) carbon dioxide, water, nitrogen, and hydrogen
B) carbon dioxide, water, methane, ozone, and nitrous oxide
C) carbon dioxide, phosphorous, water, and ozone
D) carbon dioxide, methane, and carbon monoxide
E) carbon dioxide, ozone, nitrous oxide, and phosphorous

Question 53

Which process is performed by bacteria in mutualistic relationships with legumes?

A) ammonification
B) biological magnification
C) denitrification
D) nitrification
E) nitrogen fixation

Question 54

Greenhouse gases ____, which is directed back toward Earth, maintaining the temperature of the atmosphere.

A) emit heat energy
B) absorb heat energy
C) emit carbon dioxide
D) absorb solar energy
E) absorb carbon dioxide

Question 55

Which forms of nitrogen are readily usable by plants?

A) NH₃, NH₄⁺, and NO₃-
B) NH₄⁺and NO₂-
C) N₂and NH₃
D) NH₄and NH₃
E) NO₃- and NO₄-

Question 56

Once in the ocean, most of the available phosphorous ____.

A) enters marine food webs
B) enters ocean plants
C) becomes ionized
D) precipitates out of solution
E) enters a gaseous phase

Question 57

What is the main cause of carbon dioxide buildup in the atmosphere?

A) burning fossil fuels
B) deforestation
C) droughts
D) flooding
E) respiration due to overpopulation

Question 58

Burning fossil fuels has clearly resulted in ____.

A) increases in atmospheric concentrations of carbon dioxide
B) increases in extinction rates
C) increases in concentrations of carbon dioxide in soils
D) increases in carbon retention in animals
E) decreases in atmospheric concentrations of oxygen

Question 59

What was one of the primary results from the Hubbard Brook Watershed Project?

A) Deforestation increases flooding.
B) New plant species that absorb less water were discovered.
C) Pollution gravely affected the water supply.
D) Primary consumers are the most important part of the energy pyramid.
E) Trees absorb too much water and are not useful in a watershed area.

Question 60

Most available carbon is present as ____.

A) CO₂
B) CaCO₃
C) C
D) HCO₃¯
E) N₂

Question 64

Climate change leads to ____, which releases additional carbon dioxide into the atmosphere.

A) increased frequency and severity of forest fires
B) increased logging
C) increased size of polar ice caps
D) sea level reductions
E) increased severity of volcanic eruptions

Question 65

Which factor is least useful for making predictions about how urbanization and climate change will affect the carbon cycle?

A) the architecture of the canopy of trees overhead
B) leaf positioning
C) leaf losses
D) timing of natural events
E) extent of agricultural practices

Question 66

Ocean acidification is caused by ____.

A) global warming
B) nitrogen fertilizer runoff
C) phosphorous fertilizer runoff
D) transfer of carbon dioxide from the atmosphere to the ocean
E) transfer of carbon dioxide from the ocean to the atmosphere

Question 67

How do agricultural practices affect the nitrogen cycle?

Question 68

What have you learned in the chapter about how humans can minimize their effects on food webs and nutrient cycles?

Question 69

What are the specific environmental consequences of a phytoplankton bloom?

A) An increase in phytoplankton acidifies ocean water.
B) Phytoplankton are decomposed by aerobic bacteria, which depletes the surrounding water of oxygen.
C) Phytoplankton fix nitrogen in the water causing nitrification.
D) Phytoplankton are decomposed by anaerobic bacteria which enriches the surrounding water with oxygen.
E) Phytoplankton use up hydrogen ions, which decreases the acidity of the surrounding water.

Question 70

A small decrease in seawater pH was shown to have a significant effect on ____.

A) climate change
B) the oceanic sink for carbon dioxide
C) gene expression in sea urchin larvae
D) genes expression in zooplankton
E) carbon dioxide accumulation in the ocean

Question 71

Where do terrestrial plants obtain the necessary carbon for photosynthesis?

Question 72

Fossil fuels are the result of buried organisms where low oxygen levels existed.

Question 73

A large percentage of energy passes on from one trophic level to the next.

Question 74

What is thought to be responsible for the worldwide deaths of corals and their endosymbiotic algae?

A) ocean acidification
B) nitrogen fixation
C) soil runoff
D) declining primary productivity
E) depletion of oxygen in the oceans

Question 75

In aquatic ecosystems, CO₂reacts with water to form ____.

A) HCO
B) HNO₃
C) CaCO₃
D) CO
E) H₂CO₃

Question 76

How is the net primary productivity of an ecosystem calculated?

Question 77

Humans have disrupted the nitrogen cycle primarily by ____.

A) irrigation
B) cutting down forests
C) using nitrogen-containing fertilizers
D) crop rotation
E) leaching

Question 78

Scientists estimate that carbon dioxide in the atmosphere has increased by 35% in the last 150 years.

Question 79

The Amazon rainforest's declining ability to withdraw CO₂from the atmosphere has not been attributed to increased ____.

A) logging
B) farming
C) tree mortality rates
D) logging bans
E) fires

Question 80

Which factor has caused primary productivity in Amazon forests to decline steadily over the past 30 years?

A) ocean acidification
B) nitrogen fixation
C) soil runoff
D) increasing droughts
E) depletion of oxygen in the atmosphere