BIO 262 Lecture Notes - Lecture 5: Primary Production, Lightdark, Herbivore
28 Apr 2019
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Document Summary
Energy flows from one group of organisms to the next in chains or webs. 1st law of thermodynamics energy not created or destroyed. Usually expressed as a rate (per year) Starts with primary producers within ecosystem since they set the limit for all trophic levels above. Can express amount of carbon fixed by primary producers within an ecosystem = primary productivity. The process whereby plants, algae, and cyanobacteria (primary producers) capture light energy & transform it to chemical energy in bonds of carbohydrate: This rate is referred to as primary productivity. 6co2 + 6h2o c6h12o6 + 6o2. For each g of c assimilated, 39 kj energy stored. Gross primary production = total energy assimilated by primary producers. Net primary production = energy accumulated (stored) by primary producers. Gross - net = respiration, the energy consumed by producers for maintenance and biosynthesis. A number of methods are used for measuring productivity: Light/dark cycles of plants (net production - respiration )
