4.3 Succession

1. 4.3 Succession How ecosystems recover from disturbances

2. Primary & Secondary Succession • What is ecological succession? • It is a series of predictable changes that occur in a community over time • 2. What is primary succession? • Succession that occurs on surfaces where no soil exists (no life) • 3. When a disturbance changes a community without removing the soil, what type of succession follows? • Secondary succession

3. 4. Describe the process of ecological succession • Disturbance occurs - > plants begin regrowth, more animals reenter community • 5. Why does secondary succession typically proceed faster than primary succesion? • Primary takes out the soil whereas secondary still has soil

4. Venn Diagram- Compare two types of ecological succession • Primary Both Secondary - Occurs on newly exposed surfaces (Bare rock, no soil) - Takes a longer amount of time • Occurs when a disturbance does not destroy the soil • Takes less time than primary Ecosystems grow and become more mature and complex

5. Picture Panels – Following volcanic eruption • - Correct order of panels: (from left-right) • 1, 3, 4, 2 • 1: Volcano has erupted and covered area with rocks and ash. No organisms living here • 2: pioneer species arrive (lichen) and as they die and decay they weather rock to form soil • 3: soil accumulates, allowing grasses to grow • 4: more plant species, trees able to grow

6. Climax Communities*Check for KEY concepts (Bolded sentences) • 8. After a natural disaster occurs in a healthy ecosystem, secondary succession will cause the ecosystem to return to its original ________. • Climax community • 9. The clearing of a rain forest is the example of a ______________ drastic enough to prevent the original climax community from reforming. • Human-caused disturbance

7. 10. During _________ succession, chance plays a large role in determining which pioneer species arrives in an area first. • Primary • 11. What are the two kinds of disturbances that change ecosystems? Give an example of each • Natural – volcano, flood, hurricane, tornado • Human-caused – clearing rain forest, farmer clearing field, controlled burning

8. Many abiotic and biotic factors determine how quickly ecological succession can cause a climax community to develop in an area. Give two factors that contribute to developing a climax community. No major disturbances occurring • Basic necessities: Sun, water, etc. • More soil forming • Pioneer species • Increasing plant species • More niches available Development of a climax community