BIOL 103 Lecture Notes - Lecture 12: Trophic Cascade, Primary Production, Persistent Organic Pollutant
27 Nov 2016
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Document Summary
Primary producer conduit where energy enters ecosystem. Ex: autotroph synthesizes its own food from inorganic sources. Primary producers are basis of ecosystem because they transform energy from sunlight or inorganic compounds into the chemical energy stored in sugars. Npp is critically important because it represents amount energy available to other components of ecosystem consumers and decomposers. Decomposers obtain energy by feeding on remains of other organisms or waste products. Four components of a system are linked by movement of energy and nutrients. Gross primary productivity: total amount of photosynthesis in a given area and time period. Gross photosynthetic efficiency: ratio of gross primary productivity to the total incoming solar radiation. Of gross primary production, only 45% went to npp, other 55% used for maintenance activities. Biomass represents chemical energy, biologists have identified feeding levels in ecosystems. Organisms obtaining energy from same type of source occupy the same trophic feeding level. Food chains and food webs: connects trophic levels.
