1. Changes in Ecosystems: Ecological Succession

2. Definition: Primary or Secondary
Series of ~predictable, natural and gradual changes that occur in a community over time

3. Primary Succession Begins in a place without any soil
Sides of volcanoes
Landslides
Glacier melting exposing bare rock
Starts with the arrival of living things such as lichens that do not need soil to survive
Called PIONEER SPECIES

4. LICHENS: Symbiotic fungus/algae: -break down rock to make soil
-Nitrogen fixation
-add organic material to rock/soil when they die and decompose

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

7. Primary Succession Some die  adds more organic material
The soil layer thickens, and grasses, wildflowers, and other plants begin to grow

8. Primary Succession These plants die adding more nutrients to the soil
Shrubs and tress can grow now

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

10. Primary Succession

11. Secondary Succession
Begins in a place that already has soil and was once the home of living organisms
Example: after forest fires, hurricane or other disturbance
Occurs faster and can sometimes have different pioneer species than primary succession

12. Secondary Succession

13. Climax Community
A stable group of plants and animals that is the end result of the succession process