Ecosystems Studying organisms in their environment organism population

Ecosystems

Studying organisms in their environment organism population community ecosystem biosphere

Essential questions § What limits the production in ecosystems? § How do nutrients move in the ecosystem? § How does energy move through the ecosystem?

Ecosystem § All the organisms in a community plus abiotic factors u ecosystems are transformers of energy & processors of matter § Ecosystems are self-sustaining u what is needed? § capture energy § transfer energy § cycle nutrients

Ecosystem inputs constant energy flows input of through energy nutrients cycle Matter cannot Don’t forget laws of or bethe created Physics! destroyed nutrients can only cycle biosphere inputs § energy § nutrients

Generalized Nutrient cycling consumers producers consumers decomposers nutrients ENTER FOOD CHAIN made available = made available to producers Decomposition connects all trophic levels abiotic reservoir geologic processes return to abiotic reservoir

Carbon cycle CO 2 in atmosphere Diffusion Respiration abiotic reservoir: § CO 2 in atmosphere enter food chain: Combustion of fuels = § photosynthesis carbon fixation in Industry and home Calvin cycle Photosynthesis recycle: § return to abiotic: § respiration Plants § combustion Animals Dissolved CO 2 Bicarbonates Photosynthesis Animals Plants and algae Carbonates in sediment Deposition of dead material Fossil fuels (oil, gas, coal)

Nitrogen cycle Carnivores abiotic reservoir: § N in atmosphere enter food chain: § nitrogen fixation by soil & aquatic bacteria recycle: Herbivores § decomposing & nitrifying bacteria return to abiotic: § denitrifying bacteria Birds Plankton with nitrogen-fixing bacteria Atmospheric nitrogen Plants Death, excretion, feces Fish excretion Decomposing bacteria amino acids Ammonifying bacteria loss to deep sediments Nitrifying bacteria soil nitrates Nitrogen-fixing bacteria (plant roots) Nitrogen-fixing bacteria (soil) Denitrifying bacteria

Phosphorus cycle Plants Land animals Soluble soil phosphate Loss in drainage abiotic reservoir: § rocks, minerals, soil enter food chain: § erosion releases soluble phosphate § uptake by plants recycle: § decomposing bacteria Animal tissue & fungi Urine and feces return to abiotic: § loss to. Decomposers ocean (bacteria and sediment fungi) Rocks and minerals Decomposers Phosphates (bacteria & fungi) in solution Animal tissue and feces Aquatic animals Plants and algae Precipitates Loss to deep sediment

abiotic reservoir: § surface & atmospheric water enter food chain: § precipitation & plant uptake Solar energy recycle: § transpiration return to abiotic: Evaporation§ evaporation & runoff Water cycle Transpiration Water vapor Precipitation Oceans Runoff Lakes AP Biology Percolation in soil Groundwater Aquifer

Transpiration Remember transpiration?

Breaking the water cycle § Deforestation breaks the water cycle u groundwater is not transpired to the atmosphere, so precipitation is not created forest desertification

Repairing the damage § The Greenbelt Movement u u planting trees in Kenya restoring a sustainable ecosystem establishing democracy empowering women Wangari Maathai Nobel Peace prize 2004

Studying ecosystems Hubbard Brook Experimental Forest 7800 acres 38 acre deforestation

Effects of deforestation 40% increase in runoff u loss of water § 60 x loss in nitrogen § 10 x loss in calcium loss into surface water Concentration of nitrate (mg/l ) 80 nitrate levels in runoff AP Biology 40 loss out of ecosystem! 4 2 Why is 0 nitrogen 1965 so important? Deforestation 1966 1967 Year 1968

Ecosystem inputs energy flows through nutrients cycle biosphere inputs § energy § nutrients

Energy flows through ecosystems sun secondary consumers (carnivores) primary consumers (herbivores) producers (plants) loss of energy

Food chains § Trophic levels feeding relationships u start with energy from the sun u captured by plants u Level 4 Tertiary consumer top carnivore Level 3 Secondary consumer carnivore Level 2 Primary consumer § 1 st level of all food chains usually go Level 1 Producer up only 4 or 5 levels § inefficiency of energy transfer u all levels connect to decomposers sun heterotrophs herbivore autotrophs Decomposers Bacteria Fungi

sun Inefficiency of energy transfer § Loss of energy between levels of food chain u To where is the energy lost? The cost of living!� 17% growth only this energy moves on to the next level in the food chain energy lost to daily living 33% cellular respiration 50% waste (feces)

Ecological pyramid sun § Loss of energy between levels of food chain u can feed fewer animals in each level 1 100, 000 1, 000, 000

Humans in food chains § Dynamics of energy through ecosystems have important implications for human populations u how much energy does it take to feed a human? § if we are meat eaters? § if we are vegetarian? What is your ecological footprint? !

Food webs § Food chains are § linked together into food webs Who eats whom? u a species may weave into web at more than one level § bears § humans w eating meat? w eating plants?

Any Questions? ? We’re working on a lot of them! AP Biology 2006 -2007