1. 4.3: Succession

2. Ecological Succession
gradual changes in the types of species that live in an area
~ changes until it reaches its stable ecosystem

3. Primary Succession begins in a place without soil (bare rock)
~ glacial retreat; volcanic eruption
volcanic rock – NOT soil!

4. primary succession begins with a pioneer species – group of organisms that begin the soil-building process
usually lichens (rootless plants)

5. soil starts to form as lichens and the forces of weathering break down rocks into smaller pieces
when lichens die, they decompose and add small amounts of organic matter to make soil

6. simple plants like mosses and ferns can grow in the new soil

7. simple plants die, adding more organic material
soil layer thickens then grasses, wildflowers, and other plants begin to take over

8. these plants die, and they add more nutrients to the soil so shrubs and trees can survive

9. Climax Community
stable group of plants and animals that is the end result of the succession process
does NOT always mean big trees
Examples: grasses in prairies;
cacti in deserts

10. typical hardwood forest succession
Starts with BARE ROCK – no soil initially.

12. 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
Examples: after forest fires; abandoned farms

13. Starts WITH soil – not bare rock!