Download How Ecosystems Change A. 1. 2.

Name
Date
Class
C22L3
Lesson Outline
LESSON 3
How Ecosystems Change
A. How Land Ecosystems Change
1.
is the process of one ecological community changing
into another.
2. The final stage of succession in a land ecosystem is the
,
which is stable for long periods of time. In these communities,
of the same species tend to replace each other
over time.
3. Climax communities differ depending on the
that they
occur in.
4.
is ecological succession that occurs in areas where there
is little or no soil.
5. The first species that colonize new or undisturbed land are
.
These species include some
and
.
6. After a volcano erupts, molten
cools and hardens into
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
bare rock.
a.
spores are carried by the wind and settle on the rock.
Lichens release
that break down the rock.
b. Broken-down rock and nutrients from decaying lichens help
create
c.
.
from mosses and ferns settle in thin soil on the side
of a volcano, and plants soon sprout.
d. Plant parts help build up the
layer.
e. After many years, the soil becomes deep enough for many different types
of
7.
to grow.
takes place in areas where ecosystems have been
disturbed.
a. During secondary succession, a(n)
might develop
over time.
b. Open fields can become a(n)
if they are left
undisturbed.
Biomes and Ecosystems
49
Name
Date
Class
C22L3
Lesson Outline continued
B. How Freshwater Ecosystems Change
1. Freshwater ecosystems change over time in a natural, predictable process
called
2.
.
carried by rainwater and streams accumulate on the
bottoms of ponds, lakes, and wetlands. The
organisms add to the buildup of soil.
of dead
3. As time passes, more and more soil accumulates. Eventually, so much has collected
that the water disappears and the area becomes
.
4. As decaying organisms fall to the bottom of a wetland, lake, or pond, they add
to the water.
a.
is the process of a body of water becoming
nutrient-rich.
b. Humans contribute to eutrophication when fertilizers or pollution run off into a
pond or lake, increasing
concentrations.
c. High nutrient levels in freshwater bodies support large populations of
up
50
.
Biomes and Ecosystems
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
and other microscopic organisms. When these
organisms die, their bodies decay and add to the buildup of soil, speeding