1. ECOLOGY: SUCCESSION

2. IMPORTANT TERMS Ecological Succession – A series of predicable changes that occur in a community over time. Primary Succession – Begins in an area with no remnants of the old community. Secondary Succession – Occurs in areas where the original community has not been completely destroyed. Pioneer Species – The first species to colonize a barren area.

3. BRAINSTORMING Does succession involve changes to the whole ecosystem? Can you think of any examples of primary succession? Can you think of any examples of secondary succession?

4. KRAKATAU Explosive eruption in 1883 Seismically active for several years before eruption Completely wiped out the island

5. KRAKATAU

6. PRIMARY SUCCESSION Succession that begins in an area that does not have any biotic factors left. Primary succession occurs after: Volcanic eruptions Retreating glaciers Any event that results in the complete destruction of a community

7. PRIMARY SUCCESSION

8. A very slow process Environment changes over time in response to new factors that emerge New organisms interact with abiotic factors to influence the ecosystem Subsequent species emerge in response to changes in the ecosystem

9. PIONEER SPECIES The first species to colonize an area that previously had no biotic factors. Pioneer species change the environment to make it habitable for more species Lichen A combined lifeform composed of a fungus and an alga (or cyanobacteria) Nitrogen-fixing organism; adds nutrients to soil (begins nitrogen cycle again)

10. SECONDARY SUCCESSION Succession that occurs in ecosystems that have been altered but that still maintain some elements from the original community. Process occurs much faster than primary succession. Commonly occurs after natural disturbances: Hurricanes Wildfires Human activity

11. SECONDARY SUCCESSION

12. WHY DOES SUCCESSION OCCUR? All organism influence their environment Competition between species

13. CLIMAX COMMUNITIES The final stage of succession that represents the most stable community. Succession does not always occur uniformly Areas with frequent disturbances may never reach stability Secondary succession frequently reproduces the original community.