1. How Ecosystems Change: Ecological Succession

2. Objectives List two examples of ecological succession.
Explain how a pioneer species contributes to ecological succession.
Explain what happens during old-field succession.
Describe how lichens contribute to primary succession.

3. ECOSYSTEMS CHANGE!!!!
Changes in ecosystems can cover a large area or a small area.
Changes in ecosystems may take hundreds or thousands of years.
Changes in ecosystems happen without humans doing anything!!!!!!

4. Definition:
Natural, gradual changes in the types of species that live in an area; can be primary or secondary
The gradual replacement of one plant community by another through natural processes over time

5. Primary Succession Begins in a place without any soil
Sides of volcanoes
Landslides
Sand dunes
Starts with the arrival of living things such as lichens that do not need soil to survive
Called PIONEER SPECIES

7. Primary Succession
Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces
When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil

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