Deck 46: Ecosystem Ecology

Question 1

Ecosystem ecology is primarily concerned with

A)ecosystem stability.
B)species interactions in various types of ecosystems.
C)the synthesis of nutrients within ecosystems.
D)patterns of species diversity within ecosystems.
E)movement of energy and materials through ecosystems.

Answer 1

E

Question 2

Biogeochemical cycles involve

A)the movement of chemicals through ecosystems.
B)just those nutrients that are limiting for organisms.
C)the nutrients used solely by primary producers
D)all chemical elements plus light energy.
E)None of these choices are correct.

Answer 2

A

Question 3

What is gross primary production?

A)The carbon fixed during photosynthesis.
B)The carbon fixed after cellular respiration is accounted for.
C)Energy released by primary consumers.
D)Photosynthetic production plus energy recycled by detritivores.

Answer 3

A

Question 4

The replacing forests with agricultural or urban areas can significantly affect the water cycle.Why is this?

A)Less moisture is evapotranspired into the atmosphere after deforestation.
B)The level of soil nutrients is lower after deforestation.
C)The rate of evapotranspiration increases after deforestation.
D)Cloud cover will increase after deforestation.

Question 5

In subarctic saltmarshes,scientists have found that the addition of calcium has no effect on productivity,but additional iron does increase productivity.In this example,iron

A)is a precursor to calcium.
B)stimulates evapotranspiration.
C)biomagnifies in the marsh plants.
D)is a limiting factor.
E)blocks the effect of calcium.

Question 6

If gross primary production were to increase in an ecosystem,it would be reasonable to expect that

A)nutrients would no longer be limiting factors.
B)net primary production would not increase.
C)cellular respiration would decrease.
D)the trophic web would become more complex.
E)the biomass of herbivores would increasE.

Question 7

Which of these ecosystems has the lowest productivity?

A)tropical forest
B)temperate forest
C)savanna
D)open ocean
E)lakes

Question 8

You are studying salt marsh ecosystems and find that in one of your study sites the biomass of herbivores within it is 10 kJ/m².Based on the graph below,what would you predict about the primary productivity of this salt marsh relative to other ecosystems?

A)It would be higher than tundra,but lower than savannah.
B)It would be higher than temperate forest,but lower than tropical forest.
C)It would be higher than savannah,but lower than temperate forest.
D)It would be higher than desert,but lower than tundra.

Question 9

Trophic-level transfer efficiency averages about

A)1%.
B)25%.
C)33%.
D)10%.
E)0.1%.

Question 10

In food webs,chain lengths

A)are long and complex.
B)have at least five links.
C)tend to be short.
D)range between five and ten links.
E)are usually two links.

Question 11

A hectare of wheat fixes 32,000 kg of carbon per year through photosynthesis and uses 7,000 kg of carbon per year for cellular respiration.The net primary productivity of the wheat field is therefore _____ kg of carbon/hectare/year.

Question 12

Examine the map above (Figure 46.9),which shows indices of aquatic and terrestrial primary productivity based on concentrations of chlorophyll a.
Based on this index,primary productivity of aquatic systems:

A)is equal at all latitudes.
B)generally increases from the poles to the equator.
C)is greatest in the open ocean.
D)is usually high in warm,tropical seas.
E)tends to be high near polar regions.

Question 13

What are the most important transformers of energy in ecosystems?

A)detritivores.
B)plants and algae.
C)primary consumers.
D)bacteria.
E)secondary consumers.

Question 14

How does DDT in the environment affect many birds?

A)stunted growth of chicks
B)chronic liver failure in adults
C)neurological degeneration
D)decreased reproductive rate

Question 15

Lead is known to biomagnify and accumulates in the bones of organisms.What do you think is the fate of lead in the body of a tiger that has died of natural causes? Assume the tiger occupies the highest trophic level of its ecosystem.

A)The lead will be eliminated from the food chain because no species prey upon the tiger.
B)The lead will re-enter the food chain via decomposers breaking down the tiger's bone tissue.
C)The lead will be broken down to a non-toxic form by decomposers.
D)The lead will re-enter the food chain via evaporation and precipitation.

Question 16

How do primary producers provide energy for the food chain?

A)They break down organic molecules into inorganic elements.
B)They make their own organic molecules via photo- or chemosynthesis.
C)They receive energy from primary consumers.
D)They pass on organic substances from secondary consumers.

Question 17

The giant interconnected global ecosystem is called the

A)global community.
B)biosphere.
C)ecosphere.
D)trophic web.

Question 18

Primary production is generally highest in

A)tundrA.
B)desert.
C)wetlands.
D)tropical rain forests.
E)tropical oceans.

Question 19

The movement of chemicals through ecosystems is known as

A)gross primary production.
B)biogeochemical cycling.
C)community ecology.
D)net primary production.
E)biomagnification.

Question 20

A single oak tree can support hundreds of beetles,caterpillars and other primary consumers.This would be best represented by

A)a pyramid of biomass.
B)an inverted pyramid of biomass.
C)a pyramid of energy.
D)a pyramid of numbers.
E)an inverted pyramid of numbers.

Question 21

What do you think would result if aquatic species of nitrogen fixing cyanobacteria suffered dramatic population decreases?

A)Algae populations would decline,but run off from industrial fixation would continue to provide enough nutrients to prevent their collapse.
B)Both the aquatic and terrestrial populations of autotrophs would collapse,with the end result that all life would cease to exist.
C)Algae populations would increase because they would have less competition for sunlight after the nitrogen fixing cyanobacteria were eliminated.
D)There would be no change in aquatic autotroph populations because nitrogen fixation by cyanobacteria is negligible.

Question 22

The amount of CO² in the atmosphere is stable over a period of one year.

Question 23

The water cycle is primarily a chemical process,not a physical one.

Question 24

The process by which soil bacteria convert NH₃ or NH₄ to nitrate (NO_3-)is called

A)assimilation.
B)denitrification.
C)fixation.
D)nitrification.
E)ammonification.

Question 25

Ammonification is the conversion of ________ to NH₃ and NH₄.

A)living plant matter
B)nitrate
C)inorganic nitrogen
D)nitrite
E)organic nitrogen

Question 26

Where are the largest reserves of carbon on the planet?

A)soil and rocks
B)plants,algae,and cyanobacteria
C)rocks and fossil fuels
D)volcanoes and hot springs
E)the oceans

Question 27

Most of the Earth's phosphorus is trapped in sedimentary rocks.

Question 28

Animal biomass exceeds plant biomass in most ecosystems.

Question 29

Most transpiration occurs from the sea.

Question 30

Stirling and Drake's conducted experiments about the effects of elevated atmospheric carbon dioxide on insect herbivory.What did they conclude about the effect of elevated CO₂ on plant growth and herbivory?

A)Higher plant growth,but no change in insect herbivory.
B)No change in plant growth,but higher herbivore densities.
C)Higher plant growth,but reduced herbivore densities.
D)Higher plant growth and herbivore densities.
E)No change in plant growth,but increased herbivore density.

Question 31

All living organisms require phosphorus for ATP.

Question 32

Assimilation is the process by which inorganic substances are incorporated into organic molecules.

Question 33

Based on data from the figure above,savannahs tend to have a higher herbivore biomass than deserts.

Question 34

Using a site in Northern California,you repeat Stiling and Drake's experiments in elevated and ambient CO₂ chambers,and achieve similar results.However,you notice that for one species of herbivore,the mortality rate from predators and parasitoids is equal in the elevated and ambient chambers,while the mortality rate due to nutritional inadequacy is higher in elevated chambers.The herbivore species in question is native to Asia and has only recently arrived in the United States.What is a likely explanation for your findings?

A)The Asian herbivore does not take longer to complete development in elevated CO₂ chambers,so it is not subject to additional enemy attack.
B)CO₂ becomes toxic to the Asian herbivore at the levels found in the elevated chambers.
C)The Asian herbivore takes longer to complete development in the elevated chambers,but has very few natural enemies due to its foreign origin.
D)Individuals of the Asian herbivore species thrive in the elevated CO₂ chamber,growing so large that natural enemies no longer attack them.

Question 35

Each year,plants and algae remove approximately _______ of the CO₂ in the atmosphere.

A)half
B)100%
C)1/7th
D)50%
E)1/50th

Question 36

Zooplankton are heterotrophs.

Question 37

Insect densities tend to decrease in elevated CO²,all other factors being equal.

Question 38

What percentage of the earth's atmosphere consists of nitrogen (N₂)gas?

A)0%
B)10%
C)28%
D)44%
E)78%

Question 39

In aquatic ecosystems,zooplankton are consumed by phytoplankton.

Question 40

The process by which elevated nutrient levels lead to an overgrowth of algae and the subsequent depletion of water oxygen levels is known as

A)succession.
B)decomposition.
C)eutrophication.
D)assimilation
E)biogeochemical cycling.

Question 41

Biomagnification results in an increased concentration of bioaccumulated chemicals as one moves from upper to lower trophic levels.

Question 42

Polychlorinated biphenyls (PCBs)are toxic chemicals that were widely used in manufacturing until they were banned in the U.S.in 1977.PCBs are very persistent in the environment and bind strongly to sediments,meaning that bottom dwelling and filter feeding organisms are likely to take in PCBs as they feed.PBCs accumulate in the fatty tissues and,to a lesser extent,muscle tissues of organisms.Examine the food web below.Which organism(s)do you predict would have the highest concentration of PCBs in their tissues?

A)shrimp
B)mussels
C)seal
D)crab
E)salmon