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Ecosystem Dynamics
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Essential questions What limits the production in ecosystems?
How do nutrients move in the ecosystem? How does energy move through the ecosystem?
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Ecosystem All the organisms in a community plus abiotic factors
ecosystems are ______________________& __________________________ Ecosystems are self-sustaining what is needed? capture energy transfer energy cycle nutrients
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Ecosystem inputs nutrients cycle inputs energy nutrients
biosphere Matter cannot be created or destroyed energy flows through constant input of energy nutrients cycle nutrients can only cycle inputs energy nutrients
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Generalized Nutrient cycling
consumers consumers consumers producers decomposers decomposers nutrients ENTER FOOD CHAIN = made available to producers nutrients made available to producers return to abiotic reservoir Decomposition connects all trophic levels abiotic reservoir abiotic reservoir geologic processes geologic processes
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Carbon cycle ___________________: CO2 in atmosphere
photosynthesis = carbon fixation in Calvin cycle decomposition respiration combustion Carbon cycle CO2 in atmosphere Diffusion Respiration Photosynthesis Plants and algae Plants Animals Industry and home Combustion of fuels Carbonates in sediment Bicarbonates Deposition of dead material Deposition of dead material Fossil fuels (oil, gas, coal) Dissolved CO2
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Nitrogen cycle Atmospheric nitrogen Carnivores Herbivores Birds Plants
_____________________: N in atmosphere _____________________: nitrogen fixation by soil & aquatic bacteria decomposing & nitrifying bacteria animal wastes _____________________: denitrifying bacteria Atmospheric nitrogen Carnivores Herbivores Birds Plankton with nitrogen-fixing bacteria Plants Death, excretion, feces Fish Nitrogen-fixing bacteria (plant roots) Decomposing bacteria amino acids excretion Ammonifying bacteria Nitrogen-fixing bacteria (soil) loss to deep sediments Nitrifying bacteria Denitrifying bacteria soil nitrates
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Phosphorus cycle _____________________: rocks, minerals, soil
erosion releases soluble phosphate uptake by plants decomposing bacteria & fungi _____________________: loss to ocean sediment Phosphorus cycle Land animals Plants Animal tissue and feces Urine Soluble soil phosphate Decomposers (bacteria and fungi) Loss in drainage Rocks and minerals Phosphates in solution Decomposers (bacteria & fungi) Animal tissue and feces Aquatic animals Plants and algae Precipitates Loss to deep sediment
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Water cycle Solar energy Transpiration Evaporation Precipitation
_____________________: surface & atmospheric water _____________________: precipitation & plant uptake _____________________: transpiration _____________________: evaporation & runoff Water cycle Solar energy Transpiration Water vapor Evaporation Precipitation Oceans Runoff Lakes Percolation in soil Aquifer Groundwater
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Remember transpiration?
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Breaking the water cycle
Deforestation breaks the __________________ groundwater is not transpired to the atmosphere, so precipitation is not created forest desert desertification
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Repairing the damage The Greenbelt Movement planting trees in Kenya
restoring a _______________ecosystem establishing democracy empowering women Wangari Maathai Nobel Peace prize 2004
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Studying ecosystems Hubbard Brook Experimental Forest 7800 acres
38 acre deforestation Hubbard Brook Experimental Forest 7800 acres
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Effects of deforestation
Why is nitrogen so important? Effects of deforestation 40% increase in runoff loss of water 60x loss in nitrogen 10x loss in calcium loss into surface water 80 nitrate levels in runoff 40 loss out of ecosystem! of nitrate (mg/l ) Concentration 4 Deforestation 2 1965 1966 1967 1968 Year
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Energy flows through ecosystems
sun secondary consumers (carnivores) loss of energy loss of energy primary consumers (herbivores) producers (plants)
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Food chains Trophic levels sun feeding relationships
Tertiary consumer Trophic levels feeding relationships start with ____________________ captured by __________ 1st level of all food chains food chains usually go up only 4 or 5 levels inefficiency of energy transfer all levels connect to ____________________ top carnivore Level 3 Secondary consumer carnivore Level 2 Primary consumer heterotrophs herbivore Level 1 Producer autotrophs Fungi Decomposers Bacteria
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Inefficiency of energy transfer
sun Inefficiency of energy transfer Loss of energy between levels of food chain To where is the energy lost? _______________________ 17% growth energy lost to daily living only this energy moves on to the next level in the food chain 33% cellular respiration 50% waste (feces)
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Ecological pyramid sun Loss of energy between levels of food chain
can feed fewer animals in each level 1 100 100,000 1,000,000,000
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Humans in food chains Dynamics of energy through ecosystems have important implications for human populations how much energy does it take to feed a human? if we are meat eaters? if we are vegetarian?
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Food webs Food chains are linked together into __________________
Who eats whom? a species may weave into web at more than one level bears humans eating meat? eating plants?
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