ELEMENTS OF ECOLOGY, 9E (SMITH

20.1 Short Answer Questions Chapter 20 Ecosystem Energetics

1) A(n) chemical reaction must absorb energy in order to proceed.
Answer: endothermic
Topic: Section 20.1
Bloom's Taxonomy: Knowledge/Comprehension

2) 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: second
Topic: Section 20.1
Bloom's Taxonomy: Knowledge/Comprehension

3) primary productivity is the total rate of photosynthesis or energy assimilated by
plants.
Answer: Gross
Topic: Section 20.2
Bloom's Taxonomy: Knowledge/Comprehension

4) The amount of accumulated organic matter found in an area at a given time is the
crop biomass.
Answer: standing
Topic: Section 20.2
Bloom's Taxonomy: Knowledge/Comprehension

5) For photosynthesis and productivity to occur, a plant must open its to take in carbon
dioxide.
Answer: stomata
Topic: Section 20.3
Bloom's Taxonomy: Knowledge/Comprehension

6) 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: compensation
Topic: Section 20.4
Bloom's Taxonomy: Knowledge/Comprehension

7) Organic carbon produced within an ecosystem is termed .
Answer: autochthonous
Topic: Section 20.5
Bloom's Taxonomy: Knowledge/Comprehension

,8) Relative net primary productivity is the ratio of net primary productivity to standing
.
Answer: biomass
Topic: Section 20.6
Bloom's Taxonomy: Knowledge/Comprehension

9) Net primary is the energy available to the heterotrophic component of the
ecosystem.
Answer: production
Topic: Section 20.8
Bloom's Taxonomy: Knowledge/Comprehension

10) efficiency is the ratio of production to assimilation, which measures how
efficiently the consumer incorporates assimilated energy into secondary production.
Answer: Production
Topic: Section 20.9
Bloom's Taxonomy: Knowledge/Comprehension

11) Within any ecosystem, the two major food chains are the food chain and the
grazing food chain.
Answer: detrital
Topic: Section 20.10
Bloom's Taxonomy: Knowledge/Comprehension

20.2 Multiple-Choice Questions

1) 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: D
Topic: Section 20.1
Bloom's Taxonomy: Knowledge/Comprehension

2) A chemical reaction requires energy to proceed. This would be
A) exothermic.
B) endothermic.
C) entropy.
D) kinetic energy.
Answer: B
Topic: Section 20.1
Bloom's Taxonomy: Knowledge/Comprehension

, 3) 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
Answer: B
Topic: Section 20.2
Bloom's Taxonomy: Knowledge/Comprehension

4) Plants assimilate energy through the process of
A) decomposition.
B) respiration.
C) photosynthesis.
D) regeneration.
Answer: C
Topic: Section 20.2
Bloom's Taxonomy: Knowledge/Comprehension

5) 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.
Answer: B
Topic: Section 20.2
Bloom's Taxonomy: Application/Analysis

6) 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.
Answer: D
Topic: Section 20.3
Bloom's Taxonomy: Knowledge/Comprehension

7) 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: A
Topic: Section 20.3
Bloom's Taxonomy: Knowledge/Comprehension