01:119:115 Lecture 26: Ecosystem Ecology
17 Jan 2019
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Ecosystem = all the organism living in a community, as well as the abiotic factors with which they interact. Trophic levels = positions in the food chain/web. Consumers = obtain energy from plants or animals. All food webs have limits to number of links. More photosynthesis = more energy = longer chains. Energetic hypothesis = suggests food chain length limited by inefficiency of energy transfer along chain. Exert strong control on a community by their ecological niches. Light energy converted to chemical energy by autotrophs. Once we know how much sunlight is captured by primary producers. Gross primary production (gpp) = total primary production. Net primary production (npp) = stored energy that is available to next level. Npp = gpp - ra (respiration, plant"s need) At each trophic level, there is less energy available than at the previous level. Net secondary production = the amount of chemical energy in food converted to new body (biomass)
