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Module 14 AP Review Preparing for the AP Exam
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Learning Goals Revisited

14-1 How do terrestrial ecosystems experience 14-3 How does succession impact species
succession? richness, biomass, and productivity?

In terrestrial communities, an area that begins with no soil As ecological succession proceeds, we generally see an
undergoes primary succession whereas an area that begins increase in species richness that plateaus or slightly declines,
with soil undergoes secondary succession. an increase in biomass that plateaus, and an initial increase
in productivity that subsequently declines.
14-2 Does succession occur in aquatic
ecosystems? 14-4 What is the importance of keystone species
and indicator species?
In aquatic ecosystems, streams and intertidal habitats that
are disturbed can become quickly recolonized by algae and Keystone species are not very abundant, but they have
invertebrate animals. Shallow lakes and ponds can slowly large effects on an ecological community as predators,
fill in with sediments over thousands of years to eventually sources of food, mutualistic species, or providers of other
become terrestrial habitats. essential services such as an important habitat. Indicator
species indicate characteristics of the ecosystem; they are
often used to quickly characterize when ecosystems have
been impacted by humans.

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AP Practice Questions Preparing for the AP Exam
Multiple-Choice Questions
Use the passage below to answer questions 1–3: (c) After several months, the species richness of the new

island is at its maximum.
A newly-formed volcanic island in the Pacific Ocean is cov- (d) After several years, the species richness of the new

ered with freshly cooled lava. After several months, researchers island has increased to include species of lichens,
observe that algae and lichens are growing on the lava rocks. mosses, and algae.
After several more years, the researchers find that there are now
larger populations of lichens as well as mosses growing on the 3. According to the passage, what evidence do the research-

rocks, and the rocks have begun to break apart. The researchers ers have to reach their conclusion?
concluded that primary succession is occurring on the island. (a) Primary succession starts with bare soil.
(b) Primary succession causes the number of species to

1. According to the passage, which species are the first to initially decrease.
colonize the freshly cooled lava? (c) Primary succession occurs after forest fires.
(a) mosses & algae (c) lichens & algae (d) Primary succession begins with colonization by algae,

(b) trees & shrubs (d) grasses & lichens
lichens, and mosses.

2. According to the passage, what can be concluded about 4. The process of succession in a shallow lake

the species richness of the volcanic island over time? (a) results in a terrestrial ecosystem.

(a) After several years, the species richness of the new (b) occurs rarely because disturbances are rare.
island is the same as it was when it was formed. (c) progresses fastest in very deep lakes.
(b) After several months, the species richness of the new (d) has no climax species.

island is decreasing.

160 UNIT 2 ■ The Living World: Biodiversity
Uncorrected proofs have been used in this sample.
Copyright © Bedford, Freeman & Worth Publishers.
Distributed by Bedford, Freeman & Worth Publishers. Not for redistribution.

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