How ecosystems evolve IAS BIOLOGY 5A:2.pptx

Presentation on how ecosystems evolve

1. How Ecosystems Evolve Learning Objectives: understand the different stages of succession from colonization to climax community

2. Definitions Succession - a process by which communities of plants and animals colonize a certain place over periods of time and they are replaced by others usually more varied communities for this to occur we need pioneer species basically how an ecosystem evolves Pioneer species - they colonize the area (bare rock, sand, clay or ice) and are part of the first stage of succession they are also called opportunists e.g. mosses, algae and fungi they can penetrate the rock surface including dissolving it with acids they secrete  they also penetrate the cracks within root hairs and hyphae the rock is broken down into smaller grains and they trap organic matter which then forms humus which initiates the soil formation climax community: a community that remains constant over time constant meaning diversity or range of species this is basically the last stage where the ecosystem has evolved to be habitable and the community that this now habitable ecosystem contains is the climax community plagioclimax community: sub- climax community where succession has been held back or deflected by human activity ( agriculture, habitat destruction, pesticides

3. Primary Succession .

4. Secondary Succession it gets destabilized by fire or volcanic eruption anything that changes or destroys organisms in the community even with this destruction the soil remains secondary succession occurs faster and eventually climax community gets re-established

5. Comparision between primary and secondary successions . Fast since there is already soil which contains seeds, roots and soil organisms checkpoint q3)

6. primary succession pics lava field moss growing on bare rock sand dunes

7. secondary succession pics summer of 1988 yellowstone wildfires caused by lightning

8. aftermath of 1988 yellowstone national park wildfire in 1989 .

9. past paper question . June 2022 q8

10. ms .

11. THANK YOU sorry if you got traumatized by fire .