Ecological Succession
Chapter 2
Section 2
Bell Work
 Imagine you have been
hired to oversee the
maintenance of a forest.
 How would you evaluate
the health of the forest?
 What actions would you
take to keep the forest
healthy?
 What might be a threat to
the health of the forest?
Ecological Succession
 In 1988 large
areas of
Yellowstone
Park burned to
the ground.
 How do you
think the park
looked the
following
spring?
Ecological Succession
 The “dead” forest
began to change
 New plant growth
began
Succession
 Succession
1. Gradual development
of a community of
organisms over time
Succession
 A. Takes place in all
communities
 B. Takes place over
time
Primary Succession
Primary Succession
A. Takes place after an ecosystem is
completely destroyed, including its soil
B. There is no soil in this area, usually just bare
rock
Example: volcanic eruption
Steps in Primary Succession
 1. After an volcanic
eruption, lava covers
the land and hardens
into rock
Primary Succession
2.Lichens begin to form on rocks
A. Lichens-plant like organism that is a fungus
and algae
B. Acids from the lichens begin to break down
the rock
C. These pieces of broken rock and the
remains of dead lichens start forming soil
Pioneer species- first organisms to grow in a
succession
example-lichens
Primary Succession
3. After many years
A. The soil is deep enough for mosses to grow
B. Mosses replace lichens
C. Tiny organisms like insects live the in the
lichens and mosses
Their remains add to the soil
Primary Succession
 4. Over time
Soil layer thickens
 Moss is replaced by
ferns
Next
 Growth of grasses and
wildflowers
Once the soil is deep
enough:
 Shrubs and small
trees come into the
area
Primary Succession
 5. After hundreds or
even thousand of
years
The soil may be deep
enough to support a
forest
 The final stage of
succession is the
climax community
Primary Succession
Secondary Succession
Secondary Succession
Changes that takes place after an environment
is disrupted in some way (the soil must remain
intact)
Example-forest fire, hurricane, farm land left unused
Secondary Succession
 1. fast growing
grasses and nonwoody plants appear
Secondary Succession
2. Larger shrubs move in
Secondary Succession
 3. Fast growing trees
(such as pines) move
in
 4. These are followed
by slower-growing
hardwood trees
Secondary Succession
 5. As new plants take
root and grow,
animals begin moving
back in the
ecosystem
 Succession ends with
a climax community
(when species have
adapted to the
average conditions in
that area)
Secondary Succession