ENV100Y5 Lecture Notes - Lecture 5: Arthur Tansley, Millennium Ecosystem Assessment, Ecosystem Ecology
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ENV100Y5 Full Course Notes
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Document Summary
Topics: what are ecosystems, ecosystem services, energy in ecosystems, biogeochemical cycles. What is an ecosystem: a way of looing at organisms and their interactions with the environment as an integrated system, focuss on functions, processes, fluxes (energy, nutrients), biogeochemical cycles, etc. Sysems thinking in ecology: ecosystems are nested and hierarchical, ecosystems are dynamic, boundary between the biotic and abiotic components is often blurred. Inputs, outputs, feedback loops, resistance & resilience, emergent properties. Inputs and outputs: closed syste(cid:373): (cid:373)atter does(cid:374)"t arri(cid:448)e or lea(cid:448)e, open system matter arrives and leaves. Feedback loops: negative feedback: stabilizing, e. g. density dependent population regulation, positive feedback: destabilizing, e. g. loss of arctic ice. Ecosystem stability resistance = system resists change and remains stable despite a disturbance resilience = system changes in response to a disturbance, but later returns to its original state. Emergent properties: (cid:862)(cid:449)hole is (cid:373)ore tha(cid:374) the su(cid:373) of its parts(cid:863)
