1. Changes in Ecosystems: Ecological Succession

2. What is Ecological Succession? 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

3. Primary Succession Begins in a place without any soil: »Sides of volcanoes »Landslides »Flooding First, lichens that do not need soil to survive grow on rocks Next, mosses grow to hold newly made soil Known as PIONEER SPECIES

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

5. 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

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

8. Primary Succession 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

9. Primary Succession These plants die, and they add more nutrients to the soil Shrubs and trees can survive now

10. 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

11. 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 fires

15. Climax Community A stable group of plants and animals that is the end result of the succession process Does not always mean big trees –Grasses in prairies –Cacti in deserts

16. Stages Primary Succession Stage 1 – Bare rock is exposed and came from a volcano or exposed rock from a melted glacier Stage 2 – Lichen and moss arrive – pioneer species Stage 3 – Rocks break down and grasses arrive Stage 4 – Small shrubs and herbivores arrive Stage 5 – Large shrubs, young trees, and predators arrive Stage 6 – Mature trees and large predators and herbivores arrive

17. Stages Secondary Succession Stage 1 – A natural event removed vegetation and exposes bare soil (fire, flood, farming) Stage 2 – Only nutrient-rich soil is present Stage 3 – Flowers and grasses begin to arrive Stage 4 – Small shrubs and herbivores arrive Stage 5 – Large shrubs, young trees, and predators arrive Stage 6 – Mature trees and large predators and herbivores arrive

18. Exit Ticket (primary or secondary) 1. Mature trees and large predators and herbivores arrive 2. Rocks break down and grasses arrive 3. A natural event removed vegetation and exposes bare soil (fire, flood, farming) 4. Bare rock is exposed and came from a volcano or exposed rock from a melted glacier