1. Succession in Ecosystems
JH-KEADLE
Succession in Ecosystems

2. What caused this?

3. What caused this?

4. Equilibrium What did the events do to the earth?
How did the events do this?
What part of the earth was affected?
What differences were there between the two events?

5. Equilibrium Ecosystems try to maintain equilibrium
Equilibrium is a state of balance (similar to homeostasis)
Major events in an ecosystem can upset the equilibrium
tornado/hurricane
flood
fire
drought
disease

6. Succession
Series of predictable changes that occur in a community over time
Succession allows an area to recover after a catastrophic event
Primary succession
Secondary succession

7. Succession Begins with a pioneer species
can usually perform photosynthesis
Once equilibrium is reached, it is called a climax community
Climax communities are different for each area

8. Primary Succession
Occurs on an area of newly exposed rock, sand, lava, or any area that has not been occupied by a living (biotic) community.
New island created by volcano
Rock uncovered by glacier
Takes a very long time

9. Steps of Primary Succession
Pioneer species come in
Mosses and lichens that help break down rock to form soil
Plant seeds come in on birds, animals, wind, water and begin to grow
Eventually, primary succession will lead to a community of organisms in equilibrium

10. Primary Succession

11. Example of Primary Succession
Glaciers scrape the Earth as it moves. Some land may have been buried under ice for thousands of years.

12. Example of Primary Succession
As the glacier melts, rocks are left behind. After about a year, lichens begin to grow on the rock surface. Lichens slowly weather the rock, creating the beginning of soil.

13. Example of Primary Succession
After the lichens create cracks in the rocks, mosses begin to grow in the cracks. The moss further weathers the rock, forming more soil.
Both lichens and moss are pioneer species

14. Example of Primary Succession
Once enough soil has been formed, weeds and small shrubs may follow.

15. Example of Primary Succession
As the soil is built up and enriched by dead plant material, it can support small trees that will mature into a forest.

16. Primary Succession

17. Secondary Succession
Series of changes that occur after a disturbance to an existing ecosystem
Can be a plowed field, a forest or pasture after a fire etc…
Occurs faster than primary succession because there is already soil

18. Secondary Succession
A wildfire goes through a grassland burning all of the plant life. Many of the animals are able to escape by running, flying, or burrowing in the ground.

19. Example of Secondary Succession
The pioneer community is usually made up of grasses and weeds. Insects, small mammals, and reptiles make their homes there.

20. Example of Secondary Succession
Small shrubs and trees come in next. Larger mammals sometimes begin moving in to the area.

21. Example of Secondary Succession
As the shrubs and trees grow taller and begin to reproduce, the ecosystem becomes stable.

22. Secondary Succession

23. Yellowstone Fires

25. 40 Picture D shows the first step of which process? A wild fire
B primary succession
C secondary succession
D man-made damage
41 Which picture shows the last
step of secondary succession? A D C B

26. 44 In which of the scene’s will secondary succession most likely occur?
A A only
B B only
C C only
D none