BIL 160 Lecture Notes - Lecture 19: Genetic Drift, Phytoplankton, Bioremediation
28 Apr 2016
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Document Summary
Secondary production = amount chemical energy in food converted to new biomass. Production efficiency is fraction of energy stored in food not used for respiration: net 2ndary production / assimilation of primary production, insects 40% or more, fishes around 10, birds and mammals around 1-3% Pyramid of biomass: dry and weigh all mass of all organisms, sometimes upside down in some aquatic environments. Phytoplankton make enough nutrients to have more of them. Biogeochemical cycles: life depends on recycling chemical elements, carbon, sulfur, nitrogen and oxygen all in gaseous form, solid elements like calcium, potassium and phosphorous. Hubbard brook forest experiment: clear cut a big area, measured water runoff and nitrate in deforested area. Carbon cycle: sink in atmosphere, fixed by plants. Phosphorous cycle: in rocks or marine origin. Decomposition and rates: play key role in patterns of chemical cycling, controlled by temp, moisture. Disturbances: biological communities can recover from many types.
