Deck 18: Primary Production and Energy Flow

Question 1

The rate of primary production on the Serengeti grassland is positively correlated with

A) rainfall.
B) moderate grazing.
C) high-intensity grazing.
D) both rainfall and moderate grazing.
E) both rainfall and high-intensity grazing.

Answer 1

D

Question 2

Which of the following is the correct relationship between gross primary production (GPP), net primary production (NPP), and respiration (RESP)?

A) GPP = NPP - RESP
B) RESP = GPP + NPP
C) NPP = GPP - RESP
D) NPP = GPP + RESP
E) None of the choices are correct.

Answer 2

C

Question 3

The production of new organic matter, or biomass, by autotrophs in a system is called ________.

A) primary production
B) primary construction
C) trophic production
D) trophic gain
E) autotrophic gain

Answer 3

A

Question 4

The low productivity of arctic tundra ecosystems results

A) entirely because tundra has low evapotranspiration.
B) entirely because tundra soils are low in nutrients.
C) entirely because tundra soils retain water poorly.
D) because tundra soils have low nutrients and retain water poorly.
E) because tundra has low evapotranspiration and low-nutrient soils.

Question 5

Nitrogen stable isotopes are useful tools for the study of food web structure because isotope ratios

A) change in predictable ways across trophic levels.
B) often vary among alternative food sources for a consumer.

Question 6

Net primary productivity is the primary productivity of an ecosystem, after subtracting energy lost in

A) dead plant tissues.
B) inedible plant tissues.
C) respiration by primary producers.
D) respiration by primary consumers.
E) inefficiencies of photosynthesis.

Question 7

The "trophic cascade hypothesis" emphasizes the role of

A) nutrients in controlling primary productivity.
B) nutrients in controlling primary consumption.
C) consumers in controlling primary productivity.
D) grazing by herbivores in controlling ecosystem nutrient levels.
E) primary productivity in controlling primary and secondary consumption.

Question 8

Primary production is lowest in which ecosystem?

A) Creosote bush desert
B) Annual grassland
C) Subalpine forest
D) Temperate deciduous forest
E) Tropical forest

Question 9

"Actual evapotranspiration" for an ecosystem refers to the amount of water that

A) is taken up from soils by plant roots.
B) evaporates from soils.
C) is transpired by plants.
D) evaporates from soils plus the amount transpired by plants.
E) could evaporate from soils, if they were kept wet at all times.

Question 10

On the Serengeti plain of eastern Africa, large grazing mammals consume what fraction of total primary production?

A) A negligibly small amount
B) About 10%
C) About 25%
D) About 66%
E) Nearly all

Question 11

Liebig's "Law of the Minimum" stated that

A) the lowest primary productivity occurs in the coldest ecosystems.
B) primary productivity is typically controlled entirely by climate.
C) primary productivity is typically controlled by both climate and soil nutrients.
D) a single soil nutrient typically limits primary productivity.
E) the highest primary productivity occurs at the lowest trophic level.

Question 12

Carnivores that feed on herbivores (or on detritivores) are referred to as

A) primary producers.
B) primary consumers.
C) secondary consumers.
D) parasitoids.
E) keystone species.

Question 13

Experimental fertilizations in the Baltic Sea suggest that primary productivity there is normally limited by

A) phosphorus.
B) nitrogen.
C) iron.
D) potassium.
E) temperature.

Question 14

Actual evapotranspiration rates are highest in ________ climates.

A) warm, moist
B) cold, moist
C) warm, dry
D) cold, dry
E) actual evapotranspiration rate is not affected by climate

Question 15

Bowman and his colleagues, who added nutrients to the alpine tundra on Niwot Ridge, Colorado, found

A) phosphorus is the main nutrient limiting primary production in all meadows.
B) nitrogen is the main nutrient limiting primary production in all meadows.
C) phosphorus is the main nutrient limiting primary production in dry meadows.
D) nitrogen is the main nutrient limiting primary production in wet meadows.
E) nitrogen and phosphorus jointly limit primary production in wet meadows.

Question 16

The major source of nutrients in surface waters of the open ocean is

A) mixing of subsurface with surface waters.
B) deposition from the atmosphere.
C) addition by ocean currents bringing nutrients from nearshore waters.
D) decomposition of dead organic material.
E) photosynthesis by planktonic algae.

Question 17

In Stephen Carpenter and colleagues' manipulations of lake food webs, increased densities of adult largemouth bass led to

A) increased rates of grazing on phytoplankton by zooplankton.
B) decreased rates of grazing on phytoplankton by zooplankton.
C) increased population sizes of planktivorous fish.
D) increased consumption of zooplankton by planktivorous fish.
E) no noticeable effects on food web structure.

Question 18

An organism's ________ describes its feeding position within an ecosystem.

A) prey level
B) production level
C) consumption level
D) trophic level
E) predator level

Question 19

Among lakes, primary productivity seems to be mainly controlled by levels of

A) light.
B) pollutants.
C) temperature.
D) nutrients.
E) None of the choices are correct.

Question 20

The terrestrial ecosystems with highest primary production are usually those that are

A) warm and wet.
B) warm and dry.
C) cool and wet.
D) cool and dry.
E) intermediate in both temperature and moisture.

Question 21

The influences of nutrients and temperatures on ecosystem properties are part of what ecologists call "bottom-up controls."

Question 22

Tilman and colleagues found that plant functional diversity was ________ plant diversity (number of species) for ecosystem productivity.

Question 23

Among marine systems, primary productivity is highest in tropical portions of the major oceans, far from terrestrial influences.

Question 24

Primary producers make up the first, or basal, ________ in most food webs.

Question 25

In an experiment, Benke (1976) found that the average mass gain per larva was 2.909 mg/larva and the mean larval density was 64.6 larvae/m². Please calculate the secondary production (only one significant digit after the decimal).

Question 26

Match the evidence

A) Higher lake productivity
B) Tree diversity
Higher forest primary production

Question 27

On the Serengeti plain of eastern Africa, intensive grazing by large mammals greatly decreases primary productivity in the grazed areas.

Question 28

Functional diversity is an important component of biodiversity.

Question 29

The total amount of energy fixed by autotrophs in an ecosystem is called ________.

Question 30

To test if a nutrient limits ecosystem productivity, you should

A) analyze nutrient availability.
B) measure ecosystem productivity.
C) add different nutrients and measure ecosystem productivity.
D) add nutrients.

Question 31

The number of trophic levels in an ecosystem is limited by

A) the number of tertiary consumers.
B) the loss of energy with each transfer between trophic levels.
C) the gain of energy with each transfer between trophic levels.
D) the rate at which organisms can recycle energy within the ecosystem.
E) the rate at which secondary consumers consume their prey.

Question 32

What do experimental and observational studies show clearly about how the abundance of consumers change with increased primary production?

A) Only a few trophic levels experience an higher consumer abundance.
B) Consumer abundance increases at all trophic levels.
C) Consumer abundance decreases at all trophic levels.
D) Consumer abundance does not change.

Question 33

Match the evidence

A) Higher lake productivity
B) Tree diversity
Higher algal diversity

Question 34

Increased primary production fosters ________ secondary production in terrestrial and aquatic ecosystems.