Ecological Succession

1
Ecological Succession

• Chapter 2
• Section 2

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?

3
Ecological Succession

• In 1988 large areas of Yellowstone Park burned to
  the ground.
• How do you think the park looked the following
  spring?

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Ecological Succession

• The dead forest began to change
• New plant growth began

5
Succession

• Succession
• 1. Gradual development of a community of
  organisms over time
• Succession
• A. Takes place in all communities
• B. Takes place over time

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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

7
Steps in Primary Succession

• 1. After an volcanic eruption, lava covers the
  land and hardens into rock

8
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

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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

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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

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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

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Primary Succession
13
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

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Secondary Succession

• 1. fast growing grasses and non-woody plants
  appear

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Secondary Succession

• 2. Larger shrubs move in

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Secondary Succession

• 3. Fast growing trees (such as pines) move in
• 4. These are followed by slower-growing hardwood
  trees

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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)

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Secondary Succession