2. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Communities
A community is a group of interacting populations that occupy the same area at the same time.
Oasis

3. Ecological Succession
Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
Ecological Succession
ecological succession: is the gradual replacement of one community with another as a result of changing abiotic and biotic factors.

4. There are two types of ecological succession— primary succession and secondary succession.
Primary succession always occurs first!

5. Primary Succession: when a new substrate (rock), devoid of topsoil or vegetation, is deposited and colonized
Begins with bare rock exposed by geological activity
Pioneer species appear next

6. Pioneer species: species which colonize previously uncolonized land
Ex. Lichen and grasses

7. Example:
Forest Succession
Rock →Grass →Shrubs →Open woods → Dense woods

8. Primary Succession Lava → Rock

9. Lichen or Grass

10. Grasses and Shrubs

11. Open Woods

12. Dense Woods → Stable Community

13. Chapter 3
Communities, Biomes, and Ecosystems
3.1 Community Ecology
A community that forms in an area of exposed rock that does not have any topsoil is primary succession.

14. Animal succession always follows plant succession
Example:
Flora (vegetation):
Grass → Shrubs → Woods

15. Fauna (animals):
Pheasant → Grouse → Fox

16. Bog in Minnesota

17. Later Succession of Bog

18. Climax Community: The stable, mature community that results from little change in composition of species.
What does Michigan’s climax community look like?

19. Secondary Succession: occurs after a community has been removed but the soil remains intact
May occur at any point after primary succession

20. Usually occurs after man or nature has changed the community
Example: farming, fire, flood, windstorm

22. Fire

23. New Growth After Fire

24. Gopher Tortoise