1. Unit 9: Ecology What are the changes that occur in a community over time? SB4c. Relate environmental condition to successional changes in ecosystems.

2. Types of succession: 1. Primary Succession
Life starts from scratch
Ex. Volcanic eruptions and drop in sea levels cause new land to form
Always starts with rock (new or old)

3. 2. Secondary succession Life starts over again
Ex. Fire or natural disaster
Starts with soil there already

4. Homeostasis in Communities
Organisms are adapted to maintain homeostasis in their environment. But what if the ecosystem changes? Do these changes affect the communities of organisms that live there?

5. Changes in Communities over time
Ecological Succession –A series of changes in a community in which new populations gradually replace older populations.
Succession can occur when:
a) populations decrease or increase
b) populations move in or out of an area
c) a natural disaster or human actions destroy an existing habitat

6. Order of Succession
A community starts with the pioneer species-the first species that lives in the area.
Examples: Bacteria and Lichen(fungus and bacteria or algae)

7. Order of Succession
2. Next come the grasses, small plants. The animals that would inhabit(live in) the area would be insects, small rodents

8. Order of Succession
3. Next come the small shrubs. The animals that would inhabit the area would be small animals, rodents, rabbits, snakes, fox

9. Order of Succession
4. Next come the small trees(pines, spruces). The animals that would inhabit the area would be deer, coyote, wolves

10. Order of succession
5. Last come the large trees(maple, oak). The animals that would inhabit the area would be all animals, lions, tigers and bears, OH MY!!

11. Process of succession: How does succession happen?
The above organisms live, some will die, and decomposers will break them down to return nutrients to the soil, which makes the soil richer. This changes the environment to a better environment for different species life. When succession slows down, a diverse, stable and mature community develops. This is called the climax community.