Chapter 20 - ecosystem energetics

Question 1

) The heterotrophic component of the ecosystem is often subdivided into two subsystems: consumers and ________

Answer 1

decomposers

Question 2

An ecosystem with inputs of matter and energy is a(n) ____ ecosystem

Answer 2

open

Question 3

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

Answer 3

endothermic

Question 4

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.

Answer 4

second

Question 5

____ primary production is the total rate of photosynthesis or energy assimilated by plants.

Answer 5

Gross

Question 6

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

Answer 6

standing

Question 7

For photosynthesis and productivity to occur, a plant must open its ________ to take in carbondioxide

Answer 7

stomata

Question 8

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 8

compensation

Question 9

Organic carbon produced within an ecosystem is termed ________.

Answer 9

autochtonous

Question 10

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

Answer 10

biomass

Question 11

________ is the energy available to the heterotrophic component of the ecosystem

Answer 11

Net primary production

Question 12

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

Answer 12

Production efficiency

Question 13

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

Answer 13

detrital

Question 14

) 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.

Answer 14

D) energy is neither created nor destroyed.

Question 15

Plants assimilate energy through the process of 
A) decomposition.
B) respiration.
C) photosynthesis.
D) regeneration.

Answer 15

C) photosynthesis.

Question 16

An ecologist studying productivity in a sample of grasses measures gross primary productivityas 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.

Answer 16

B) 900 kcal / m2 / yr.

Question 17

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 increase

Answer 17

D) and mean annual rainfall increase

Question 18

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 18

A) tropical latitudes near the equator.

Question 19

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.

Answer 19

C) nitrogen and iron.

Question 20

Low-moisture conditions favor allocation by a plant to
A) leaves.
B) stems.
C) roots.
D) flowers

Answer 20

C) roots.

Question 21

Secondary production is limited primarily by
A) water availability.
B) nutrient availability.
C) primary production.
D) light availability

Answer 21

C) primary production.

Question 22

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

Answer 22

A) endothermic carnivore, such as a lion

Question 23

The base of the detrital food chain is formed by

a. primary producer
b. decomposer
c. herbivore
d. dead organic matter

Answer 23

d. dead organic matter

Question 24

In most terrestrial and many aquatic systems, the ____ food chain is the dominant pathway of energy flow

a. detrital
b. grazing
c. consumer
d. heterotroph

Answer 24

a. detrital

Question 25

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

Answer 25

a. aquatic ecosystems dominated by phytoplankton

Question 26

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

Answer 26

100 kcal

Question 27

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

Answer 27

True

Question 28

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

Answer 28

False

Question 29

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

Answer 29

True

Question 30

Net primary productivity cannot be measured in aquatic ecosystems,

Answer 30

False

Question 31

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

Answer 31

true

Question 32

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

Answer 32

false

Question 33

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

Answer 33

false

Question 34

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

Answer 34

True

Question 35

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

Answer 35

true

Question 36

In temperate rain forest, primary productivity remains relatively constant

Answer 36

false

Question 37

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

Answer 37

true

Question 38

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

Answer 38

true

Question 39

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

Answer 39

True

Question 40

Primary producers form the base of all food chains

Answer 40

false

Question 41

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

Answer 41

False

Question 42

Consumption efficiency is the ratio of ingestion to production

Answer 42

true

Question 43

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

Answer 43

false

Question 44

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

Answer 44

true

Question 45

In most ecosystems, the biomass of carnivore is greater than the biomass of producers

Answer 45

false

Question 46

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

Answer 46

false

Question 47

Brian Silliman:s research demonstrated that productivity in highly productive coastal salt marshes is controlled by bottom up forces such as physical condition and nutrient availability

Answer 47

false

Question 48

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

Answer 48

false