Deck 20: Ecosystem Energetics

Question 1

Relative net primary productivity is the ratio of net primary productivity to standing ________.

Answer 1

biomass

Question 2

Net primary productivity is generally greatest at

A)tropical latitudes near the equator.
B)subtropical latitudes (e.g.,25° of latitude).
C)temperate latitudes (e.g.,50° of latitude).
D)polar latitudes (e.g.,80° of latitude).

Answer 2

A

Question 3

In a body of water,the depth at which the availability of light is such that the rate of photosynthesis equals the rate of respiration is called the ________ depth.

Answer 3

compensation

Question 4

Where are the areas of highest NPP?

A)equator
B)arctic
C)temperate region
D)Saharan desert

Question 5

________ efficiency is the ratio of production to assimilation,which measures how efficiently the consumer incorporates assimilated energy into secondary production.

Question 6

Organic carbon produced within an ecosystem is termed ________.

Question 7

Net primary ________ is the energy available to the heterotrophic component of the ecosystem.

Question 8

Plants assimilate energy through the process of

A)decomposition.
B)respiration.
C)photosynthesis.
D)regeneration.

Question 9

A(n)________ chemical reaction must absorb energy in order to proceed.

Question 10

Net primary productivity in an ecosystem increases as mean annual temperature

A)and mean annual rainfall decrease.
B)decreases and mean annual rainfall increases.
C)increases and mean annual rainfall decreases.
D)and mean annual rainfall increases.

Question 11

Which ecosystem has the highest actual evapotranspiration?

A)creosote-bush desert
B)tallgrass prairie
C)pine forest
D)beech-maple forest

Question 12

For photosynthesis and productivity to occur,a plant must open its ________ to take in carbon dioxide.

Question 13

The ________ law of thermodynamics states that when energy is transferred or transformed,part of the energy assumes a form that cannot pass on any further.

Question 14

Within any ecosystem,the two major food chains are the ________ food chain and the grazing food chain.

Question 15

Which of the following formulas are correct regarding productivity?

A)GPP + R = NPP
B)GPP - R = NPP
C)NPP - GPP = R
D)NPP - R = GPP

Question 16

According to the first law of thermodynamics,

A)chemical reactions are exothermic.
B)entropy tends to increase.
C)potential energy tends to degrade into an unavailable form.
D)energy is neither created nor destroyed.

Question 17

________ primary productivity is the total rate of photosynthesis or energy assimilated by plants.

Question 18

A chemical reaction requires energy to proceed.This would be

A)exothermic.
B)endothermic.
C)entropy.
D)kinetic energy.

Question 19

An ecologist studying productivity in a sample of grasses measures gross primary productivity as 1000 kcal/m2/yr and autotrophic respiration as 100 kcal/m2/yr.Based on these calculations,the net primary productivity would be

A)10 kcal/m2/yr.
B)900 kcal/m2/yr.
C)1100 kcal/m2/yr.
D)10,000 kcal/m2/yr.

Question 20

The amount of accumulated organic matter found in an area at a given time is the ________ crop biomass.

Question 21

In most terrestrial and many aquatic ecosystems,the ________ food chain is the dominant pathway of energy flow.

A)detrital
B)grazing
C)consumer
D)heterotroph

Question 22

The river continuum concept suggests that one of the following is higher in headwater streams.

A)autochthonous carbon
B)allochthonous carbon
C)phytoplankton abundance
D)macrophyte abundance

Question 23

Low-moisture conditions favor allocation by a plant to

A)leaves.
B)stems.
C)roots.
D)flowers.

Question 24

In the surface waters of oceans,the two most limiting nutrients for primary productivity are

A)sulfur and phosphorus.
B)sulfur and nitrogen.
C)nitrogen and iron.
D)nitrogen and phosphorus.

Question 25

The ratio of energy consumed at the next trophic level over what is produced is known as

A)consumption efficiency.
B)trophic efficiency.
C)food chain efficiency.
D)detrital efficiency.

Question 26

The base of the detrital food chain is formed by

A)primary producers.
B)decomposers.
C)herbivores.
D)dead organic matter.

Question 27

Secondary production is limited primarily by

A)water availability.
B)nutrient availability.
C)primary production.
D)light availability.

Question 28

Which factor is the primary control of productivity in aquatic systems?

A)temperature
B)precipitation
C)light
D)salinity

Question 29

The presence of which element is highly correlated with NPP?

A)carbon
B)phosphorus
C)sodium
D)hydrogen

Question 30

Which pathway leads to the detrital food chain?

A)W
B)P
C)R
D)I

Question 31

Detrital food chains contain all of the following except

A)carnivores.
B)herbivores.
C)decomposer herbivores.
D)detritus.

Question 32

How does the open ocean have the highest relative net primary productivity while having one of the lowest mean biomass per unit area?

A)high turnover rate of plankton
B)high mean net primary productivity
C)the presence of large organisms like whales
D)having a larger third dimension of depth

Question 33

In which situation is the detrital food chain not more dominant than the grazing food chain?

A)open-water aquatic ecosystems
B)kelp forest ecosystems
C)grassland ecosystems
D)tropical forest ecosystems

Question 34

Why might secondary production be lower in grasslands than in forests?

A)because average temperatures are lower
B)because average water availability is higher
C)because primary production is lower
D)because there is a higher biomass of animals in grasslands

Question 35

Which group has the highest production efficiency?

A)mice
B)voles
C)insects
D)fish

Question 36

Rates of herbivory are highest in

A)aquatic ecosystems dominated by phytoplankton.
B)aquatic ecosystems dominated by vascular plants.
C)terrestrial ecosystems dominated by herbaceous plants.
D)terrestrial ecosystems dominated by woody plants.

Question 37

Which of the following has the highest assimilation efficiency?

A)lion
B)rodent
C)caterpillar
D)spider

Question 38

What level of productivity would one predict with high levels of water supply but low temperatures?

A)very low
B)low
C)high
D)very high

Question 39

Which of the following tree stands would you predict has the highest NPP?

A)0-1 years old
B)1-10 years old
C)30-60 years old
D)over 100 years old

Question 40

Which organism is most likely to have the highest assimilation efficiency?

A)endothermic carnivore,such as a lion
B)ectothermic carnivore,such as a snake
C)endothermic herbivore,such as a deer
D)ectothermic herbivore,such as a grasshopper

Question 41

Which region represents the highest HANPP as a percentage of local NPP?

A)Australia
B)Canada
C)South America
D)India

Question 42

When a chemical reaction results in the loss of energy from the system,the reaction is exothermic.

Question 43

The ratio of the productivity of one trophic level over what its organisms consume is known as

A)consumption efficiency.
B)trophic efficiency.
C)food chain efficiency.
D)detrital efficiency.

Question 44

NPP can be measured via satellite data because vegetation has

A)high reflectance in the NIR and low reflectance in VIS.
B)low reflectance in the NIR and low reflectance in VIS.
C)high reflectance in the NIR and high reflectance in VIS.
D)low reflectance in the NIR and high reflectance in VIS.

Question 45

In plants,low water availability favors the allocation of energy to the roots.

Question 46

Primary productivity in forests often increases during the early stages of stand development and then decreases again as the forest ages and standing biomass increases.

Question 47

Primary producers form the base of all food chains.

Question 48

The second law of thermodynamics is valid only in a closed system,such as a living organism.

Question 49

In endotherms,an increase in mass-specific metabolic rate lowers production efficiency.

Question 50

Net primary productivity cannot be measured in aquatic ecosystems.

Question 51

Estimates of HANPP range around 20 percent,yet what percent of total heterotrophic biomass do humans make up?

A)20 percent
B)50 percent
C)10 percent
D)less than 1 percent

Question 52

Secondary production in an ecosystem is always less than primary production.

Question 53

Net primary productivity is greater in the open ocean than along the coast.

Question 54

Net primary productivity is greater in areas with a long photosynthetic period than in areas with a short photosynthetic period.

Question 55

Productivity may be expressed in units of energy per unit area per unit time or in units of dry organic matter per unit area per unit time.

Question 56

If herbivores eat 1000 kcal of plant energy,approximately how much energy will be converted into the tissues of herbivores?

A)1 kcal
B)10 kcal
C)100 kcal
D)1000 kcal

Question 57

In a temperate rain forest,primary productivity remains relatively constant.

Question 58

In most marine ecosystems,autochthonous inputs of organic carbon are greater than allochthonous inputs of carbon.

Question 59

Why are there not seven or eight levels to a trophic food chain?

A)lack of biodiversity
B)lack of global energy
C)lack of trophic efficiency
D)lack of primary productivity

Question 60

Net primary productivity is greater in temperate grasslands than in tropical rain forest.

Question 61

In most ecosystems,the biomass of carnivores is greater than the biomass of producers.

Question 62

In all food chains,the flow of energy is unidirectional from the bottom to the top.

Question 63

Consumption efficiency is the ratio of ingestion to production.

Question 64

In stream and river ecosystems,the grazing food chain is of minor importance compared with the detrital food chain.

Question 65

In all ecosystems,the biomass of primary producers is greater than the biomass of herbivores.

Question 66

Wealthy nations typically have lower rates of human appropriation of net primary productivity (HANPP)than developing nations.

Question 67

In terrestrial and shallow-water ecosystems,the grazing food chain is dominant over the detrital food chain.