ENV100Y5 Lecture Notes - Lecture 23: Trophic Level, Secondary Succession, Biome
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ENV100Y5 Full Course Notes
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Session 19: species interactions and community ecology (ii) (23-10-15) It takes a lot of grass to make a hamburger! What limits length of food chains: ecological efficiency, trophic level of system can"t be huge. Keystone species: species that has a disproportionate role in structuring the community, keystone species may increase the biodiversity of a community, keystone species are not always predators: Communities respond to disturbances: resistance = remains stable, resilience = changes, but returns to original state. Succession follows severe disturbance: succession = predictable series of changes in a community following disturbance, primary succession = disturbance eliminates vegetation; soil, secondary succession = some organisms survive. Primary succession: glaciers, drying lakes, volcanic lava, pioneer species = first to arrive in a primary succession area. Secondary succession: fires, hurricanes, farming, logging, remaining organisms form building blocks for the, next species to arrive & establish. Invasive species pose new threats to community stability.
