Ecological Succession Chapter 2 Section 2 Bell Work

Ecological Succession Chapter 2 Section 2

Bell Work l 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. l How do you think the park looked the following spring? l

Ecological Succession The “dead” forest began to change l New plant growth began l

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

Primary Succession l 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 l Example: volcanic eruption

Steps in Primary Succession l 1. After an volcanic eruption, lava covers the land hardens into rock

Primary Succession l 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 l 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 l Their remains add to the soil

Primary Succession l 4. Over time ¡ Soil layer thickens l ¡ Next l ¡ Moss is replaced by ferns Growth of grasses and wildflowers Once the soil is deep enough: l Shrubs and small trees come into the area

Primary Succession l 5. After hundreds or even thousand of years ¡ l The soil may be deep enough to support a forest The final stage of succession is the climax community

Primary Succession

Secondary Succession l Secondary Succession ¡ Changes that takes place after an environment is disrupted in some way (the soil must remain intact) l Example-forest fire, hurricane, farm land left unused

Secondary Succession l 1. fast growing grasses and nonwoody plants appear

Secondary Succession l 2. Larger shrubs move in

Secondary Succession l 3. Fast growing trees (such as pines) move in l 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 l Succession ends with a climax community (when species have adapted to the average conditions in that area) l

Secondary Succession