1. C-Notes: Ecological Succession
Stnd: 6b
C-Notes: Ecological Succession
4/23/2014
Objective:
SWBAT identify the process of change in the species that make up a community.

2. ECOLOGICAL SUCCESSION
The gradual replacement of one community by another.
Ecological succession eventually leads to the formation of a stable community.
Each community slowly changes the environment. The changed environment often is more suitable for new types of organisms and less suitable for the existing organisms.
Ecological succession occurs in step stages.
A stable community is called a CLIMAX COMMUNITY.

3. SUCCESSION
Primary Succession
Occurs in an area that has no existing life.
Must begin with the formation of soil.
Example: a bare rock, rocky cliffs, sand dunes, newly formed volcanic island, newly exposed land areas.
Secondary Succession
Begins in a place that already has soil and was once the home of living organisms
Occurs faster and has different pioneer species than primary succession
Example: After Forest Fire, Tornado, Hurricane

4. PRIMARY SUCCESSION First Stage Can begin with bare rock.
Lichens are usually one of the first organisms to appear because they can live on bare rock.
The first organisms are called PIONEER SPECIES
Pioneer organisms are able to survive in harsh conditions with few nutrients.

5. Pioneer Species
Low, growing moss plants trap moisture and prevent soil erosion
Lichens break down rock to form soil.

7. Primary SUCCESSION Second Stage Third Stage Fifth Stage Fourth Stage
Grasses
Third Stage
Shrubs and Small Trees
Fifth Stage
Shade Trees
Fourth Stage
Sun Trees

8. Primary Succession
Simple plants like mosses and ferns can grow in the new soil

9. Primary Succession (2nd Stage)
The simple plants die, adding more organic material (nutrients to the soil)
The soil layer thickens, and grasses, wildflowers, and other plants begin to take over

10. Primary Succession (3rd Stage)
These plants die, and they add more nutrients to the soil
Shrubs and trees can survive now

11. Primary Succession
Insects, small birds, and mammals have begun to move into the area
What was once bare rock, now supports a variety of life

15. ECOLOGICAL SUCCESSION

16. CLIMAX COMMUNITIES
If environmental conditions in an ecosystem remain stable over long periods of time, the same species of plants and animals that make up that ecosystem continue to live and interact together.
These permanent plant and animal species make up a stable or climax community.
This is the END RESULT of the succession process
DOES NOT always mean big trees
Grasses in prairies
Cacti in deserts
There is a balance within the population and the environment.
A Climax Community remains until a drastic environmental change occurs.
Storm, Forest Fire, Flood, Volcanic Eruption
The type of climax community is determined by the abiotic factors of the area.

17. ECOSYSTEM STABILITY
Under stable environmental conditions, the number of organisms in naturally occurring populations remains constant (the same), with only small periodic changes.
A stable ecosystem will be able to resist invasion by potential competitors.
A stable ecosystem will be able to resist change in the face of disturbance.
A more diverse ecosystem will be more stable.