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1、Todays Focus:1) Nutrient cycling in ecosystems2) Human impact on ecosystems,Nutrient Cycling: Background (Pg. 1208)1) Inorganic nutrients must be recycled 2) Both biological and geological processes are involved in recycling inorganic nutrients3) Decomposition rates determine rate of recycling4),4)
2、Nutrients are in two forms, each with two states:a) Inorganici) availableii) unavailableb) Organici) availableii) unavailable ex.,Organic Compartments,Inorganic Compartments,Where materials are,KNOW Pg.1209,Biological ProcessesGeological Processes,Biological ProcessesGeological Processes,Can geologi
3、cal Processes Convert inorganic To organic?,Biological ProcessesGeological Processes,Name 1 Biological And 1 Geological Process that Converts Organic to inorganic,The water cycle: (Pg. 1210),Evaporation the movement of water from the surface into the atmosphere Transpiration the evaporative loss of
4、water by a plant Evapotranspiration the loss of surface water on land from the combined effects of evaporation and transpiration,Pg. 1210,Important components,The Carbon Cycle (Pg. 1211),Carbon Cycle: Background The movement of CARBON through an ecosystem parallels that of energy more closely than a
5、ny other chemicalOnly one method of conversion from inorganic to organic nutrientsPHOTOSYNTHESIS!,Factory,CO2,Atmosphere Boundary,Energyinput,Factory,CO2,Atmosphere Boundary,Energyinput,Whats the problem?,Factory,CO2,Energyinput,C02 acts as an insulator that traps heat, Result Global Warming!,The Ni
6、trogen Cycle (Pg. 1210-1211),Nitrogen cycle: Key concepts Nitrogen is critical for life as it is found in all amino acids (which make up proteins of organisms) Atmospheric Nitrogen is in the form of Nitrogen Gas (N2) Earths Atmosphere is 80% Nitrogen, but in the form of N2 Plants can only use two fo
7、rms of Nitrogena) NH4 (ammonium)b) NO3 (nitrate),Usable Nitrogen gets into ecosystems through one of two pathways: Atmospheric deposition NH4 and NO3 are added to soil by being dissolved in rain or by settling as a fine dustNitrogen fixation the conversion of atmospheric N2 to NH3,Soil,N2,bacteria,N
8、H3,Acid soil,NH4,Conversion of Atmospheric Nitrogen to usage nitrogen,Nitrogen Cycle: Three Important Processes: Nitrification The oxidation of NH4 to NO2 to NO3 Denitrification NO3 is converted back to N2 Ammonification NO3 is converted back to NH4,The Phosphorus Cycle: Pg. 1212,Phosphorus - Backgr
9、ound: major component of nucleic acids, phospholipids, and ATP This cycle does not involve movement through the atmospherePO4 is the only usable form,Pg. 1213,Generalized scheme for biogeochemical cycles,Some Impacts on ecosystems by Humans (Pg. 1214),1) Global Warming CO2 emission and Greenhouse ga
10、ses,Factory,CO2,Energyinput,C02 acts as an insulator that traps heat, Result Global Warming!,Greenhouse Effect The warming of Earth due to the atmospheric accumulation of CO2, which absorbs infrared radiation and slows its escape from the irradiated Earth,Global Warming CO2 emission and Greenhouse g
11、asesBiological Magnification of toxins- the increase in toxin concentration through successive trophic levels,Human use of Pesticides,Soluble in water, Collects in fatty tissue,DDT interfered with Calcium deposition,Time magazine in 1947,Global Warming CO2 emission and Greenhouse gasesBiological Mag
12、nification of toxins- the increase in toxin concentration through successive trophic levels3) Deforestation lose of nutrients and altered nutrient cycles,Large scale experiment testing the effects of clear cutting,Loss of nutrients in the absence of plants,Global Warming CO2 emission and Greenhouse
13、gasesBiological Magnification of toxins- the increase in toxin concentration through successive trophic levels3) Deforestation lose of nutrients and altered nutrient cycles4) Warfare can alter landscapes, change nutrient cycles and drastically influence an ecosystem,Use of a defoliant, agent orange,
14、 during Vietnam War,Before,After,Global Warming CO2 emission and Greenhouse gasesBiological Magnification of toxins- the increase in toxin concentration through successive trophic levels3) Deforestation lose of nutrients and altered nutrient cycles4) Warfare can alter landscapes, change nutrient cycles and drastically influence an ecosystem5) Depletion of the ozone layer : ClX + O3 O2 + XO + Cl,Free to reduce more O3,Hole in the Ozone layer over Antarctica,Consequences?,Next Time: Chapter 55 Conservation Biology,
