How ecosystems recover from disturbances 4.3 Succession How ecosystems recover from disturbances

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

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

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

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

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

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

Development of a climax community 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