Ecosystems
Studying organisms in their environment organism population community ecosystem biosphere
Essential questions! What limits the production in ecosystems?! How do nutrients move through the ecosystem?! How are humans disrupting the biosphere?
Ecosystem! All the organisms in a community plus abiotic factors " ecosystems are transformers of energy & processors of matter! Ecosystems are self-sustaining " what is needed?! capture energy! transfer energy! cycle nutrients
Ecosystem inputs nutrients cycle constant energy flows input of through energy Matter Don t cannot forget be the created laws of or destroyed Physics! nutrients can only cycle biosphere inputs! energy! nutrients
Nutrient cycling consumers consumers producers decomposers nutrients made available to producers Decomposition connects all trophic levels abiotic reservoir geologic processes
Carbon cycle CO 2 in atmosphere Diffusion Respiration Photosynthesis Combustion of fuels Industry and home Plants Animals Dissolved CO 2 Bicarbonates Photosynthesis Animals Plants and algae Deposition of dead material Carbonates in sediment Deposition of dead material Fossil fuels (oil, gas, coal)
Nitrogen cycle Carnivores Atmospheric nitrogen Herbivores Birds Plankton with nitrogen-fixing bacteria Fish loss to deep sediments excretion Death, excretion, feces Decomposing bacteria amino acids Ammonifying bacteria Nitrifying bacteria soil nitrates Plants Nitrogen-fixing bacteria (plant roots) Nitrogen-fixing bacteria (soil) Denitrifying bacteria
Phosphorus cycle Loss in drainage Plants Decomposers (bacteria & fungi) Phosphates in solution Land animals Soluble soil phosphate Urine Rocks and minerals Animal tissue and feces Decomposers (bacteria and fungi) Animal tissue and feces Aquatic animals Plants and algae Precipitates Loss to deep sediment
Water cycle Water vapor Transpiration Precipitation Evaporation Solar energy Oceans Lakes Runoff Percolation in soil Groundwater Aquifer
Breaking the water cycle! Deforestation breaks the water cycle " groundwater is not transpired to the atmosphere, so precipitation is not created forest desert
Repairing the damage! The Greenbelt Movement " planting trees in Kenya " restoring a sustainable ecosystem " establishing democracy " empowering women Wangari Maathai Nobel Peace prize 2004
Effects of deforestation 40% increase in runoff " loss of water 80! 60x loss in nitrogen! 10x loss in calcium nitrate levels Concentration of nitrate (mg/l ) 40 4 2 Deforestation loss into surface water 0 1965 1966 Year 1967 1968
Energy flows through ecosystems sun secondary consumers (carnivores) loss of energy primary consumers (herbivores) loss of energy producers (plants)
Food chains! Feeding relationships " start with energy from the sun " 1 st level of all food chains is plants " most food chains usually go up only 4 or 5 levels " all levels connect to decomposers Level 4 Level 3 Level 2 Level 1 Tertiary consumer Secondary consumer Primary consumer Producer Decomposers top carnivore carnivore herbivore Bacteria Sun Fungi
Food webs! Food chains are linked together into food webs! Who eats whom? " a species may weave into web at more than one level! bears! humans # eating meat? # eating plants?
Trophic structure! Food chains " feeding relationships sun " food chain usually 4 or 5 links! trophic levels " length of food chain limited by inefficiency of energy transfer! how much energy lost from one level to next Primary producer Primary consumer Secondary consumer Tertiary consumer
Energy transfer! Loss of energy between levels of food chain " To where is the energy lost? The cost of living! sun 17% growth only this energy moves on to the next level in the food chain 33% cellular respiration 50% waste (feces) energy lost to daily living
Ecological pyramid! Loss of energy between levels of food chain " can feed fewer animals in each level sun Numbers 1 100 100,000 1,000,000,000
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?
Nutrients & trophic levels! Energy flows through but nutrients cycle " must be recycled to be available for the next generation " decomposers return nutrients to the soil after creatures die! fungi! bacteria n u t r i e n t s decomposers