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Chapter 20
1. The first plants in a successional sequence are called the ______________.
Answer: pioneer community
2. “Primary” succession is succession that
a) involves establishment of primary producers where there were none.
b) leads to establishment of a climax community dominated by primary producers.
c) occurs on newly exposed geologic substrates, not organic soil.
d) occurs where organic soils have been exposed but not destroyed by disturbance.
e) occurs after fire or agricultural abandonment.
Answer: C
3. In the area of Glacier Bay, Alaska, the climax community is
a) hemlock forest.
b) muskeg.
c) hemlock forest on steep slopes, and muskeg on shallower slopes.
d) hemlock forest on shallow slopes, and muskeg on steeper slopes.
e) Dryas mats with scattered alders and cottonwoods.
Answer: C
4. The pioneer species at Glacier Bay, Alaska include
a) mosses.
b) Dryas.
c) alders.
d) horsetails.
e) hemlocks.
Answer: D
5. During primary succession at Glacier Bay, overall plant species diversity
a) first increases rapidly, then levels off.
b) increases steadily throughout succession.
c) increases slowly at first, then more rapidly after a few hundred years.
d) peaks at intermediate successional stages.
e) decreases steadily throughout succession.
Answer: A
6. During primary succession at Glacier Bay, species diversity continues to increase
throughout succession for which group(s) of plants?
a) tall shrubs and trees
b) low shrubs and herbs
c) mosses
d) lichens
e) all groups of plants
Answer: B
7. In secondary succession on abandoned fields in the Piedmont of North Carolina,
important pioneer species include
a) horsetails.
b) Dryas.
c) broomsedge (Andropogon).
d) pine seedlings.
e) crabgrass and horseweed.
Answer: E
8. How does canopy shading influence succession of pines and deciduous trees in the
Piedmont of North Carolina?
a) Canopy shading by deciduous trees is required for growth of pines.
b) Canopy shading by deciduous trees prevents establishment of pines until late in
succession.
c) Canopy shading by deciduous trees prevents persistence of pines in late successional
stages.
d) Canopy shading by pines prevents establishment of deciduous trees.
e) Canopy shading by pines kills deciduous trees that were established early in
succession.
Answer: C
9. In the Piedmont of North Carolina, as plant diversity increases through secondary
succession, bird diversity
a) increases at first, but then declines late in succession.
b) increases steadily through succession.
c) increases slowly at first, but then rapidly late in succession.
d) increases rapidly at first, then plateaus late in succession.
e) first decreases, but later increases.
Answer: D
10. On intertidal boulders in California, the climax community is dominated by perennial
red algae.
Answer: T
11. On intertidal boulders in California, the diversity of diatoms and algae
a) increases at first, but then declines late in succession.
b) increases steadily through succession.
c) increases slowly at first, but then rapidly late in succession.
d) increases rapidly at first, then plateaus late in succession.
e) first decreases, but later increases.
Answer: A
12. Which statement about changing ecosystem properties during succession is false?
a) biomass increases
b) soil depths decrease
c) primary production increases
d) community respiration increases
e) stream spiralling lengths decrease
Answer: B
13. A set of sites differing in successional age is called a ____________.
Answer: chronosequence
14. As Hawaiian lava flows age over 4 million years,
a) total soil phosphorous levels decrease.
b) total soil phosphorous levels increase.
c) total soil phosphorous stays about the same, but more phosphorous becomes
weatherable.
d) total soil phosphorous stays about the same, but more phosphorous becomes
refractory.
e) phosphorous limitation of primary production becomes less important.
Answer: C
15. In the “transition phase” of forest succession,
a) biomass increases rapidly as the community reorganizes.
b) biomass declines from an earlier peak.
c) biomass stays constant, but species composition turns over rapidly.
d) nutrient export increases dramatically and soils become depleted.
e) one climax community gives way to another.
Answer: B
16. During succession in Arizona streams, nitrogen retention
a) increases at first, but then declines late in succession.
b) increases steadily through succession.
c) increases slowly at first, but then rapidly late in succession.
d) increases rapidly at first, then plateaus late in succession.
e) first decreases, but later increases.
Answer: A
17. High nitrogen retention early in stream succession is probably due to
a) nitrogen fixation by aquatic fungi.
b) increasing biomass of algal and animal populations.
c) increasing nitrogen inputs from surrounding terrestrial soils.
d) increasing binding of nitrogen to developing organic sediments.
e) reduced denitrification following disturbance.
Answer: B
18. According to the “facilitation” hypothesis, pioneer species modify the environment in
ways that
a) make it more suitable for their own survival, and less suitable for other species.
b) make it less suitable for their own survival, but more suitable for survival of other
pioneer species.
c) make it less suitable for their own survival, but more suitable for survival of latesuccessional species.
d) make it less suitable for survival of all species.
e) make it more suitable for survival of all species.
Answer: C
19. According to the “inhibition” hypothesis, pioneer species modify the environment in
ways that
a) make it less suitable for other species.
b) make it less suitable for their own survival, but more suitable for survival of other
pioneer species.
c) make it less suitable for their own survival, but more suitable for survival of latesuccessional species.
d) make it more suitable for survival of all species.
e) in this model, pioneer species do not modify the environment.
Answer: A
20. Wayne Sousa’s studies of succession on intertidal boulders demonstrated which
elements of the inhibition hypothesis?
a) inhibition of mid- and late-successional species by pioneers
b) inhibition of late-successional species by mid-successional ones
c) higher mortality of pioneer species
d) all of the above
e) none of the above
Answer: D
21. Succession in old fields in the Piedmont of North Carolina involves succession driven
a) largely by facilitation
b) largely by inhibition
c) largely by tolerance
d) both by inhibition and by tolerance
e) both by facilitation and by inhibition
Answer: E
22. A tendency for a community to maintain its structure even when subject to potential
disturbance is called ____________.
Answer: resistance
23. A community in which secondary succession is very rapid has
a) high resistance.
b) low resistance.
c) high resilience.
d) low resilience.
e) high replication.
Answer: C