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

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  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 non- woody 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