2 Assessment Statements: 2.5.1 Explain the role of producers, consumers and decomposers in the ecosystem.2.5.2 Describe photosynthesis and respiration in terms of inputs, outputs, and energy transformations2.5.3 Describe and explain the transfer and transformation of energy as it flows through the ecosystem2.5.4 Describe and explain the transfer and transformation of materials as the cycle within an ecosystem.
3 Transfers vs Transformations Transfers – flows through a system, often involve changes in locationBiomass moves from producers through food chainWater moves from a river to the oceanEnergy moves from the sun to a plant leafTransformations – interactions within a system and formation of new products or changes of stateLight energy is converted to chemical energyGlucose is broken down into water and carbon dioxide
4 What is a system?System: a collection of matter, parts, or components which work together usually to perform a specific function.Systems often have inputs and outputs.For dynamic systems, by definition, one or more aspects of the system change with time.Example of a simple dynamic system: bathtub or your ‘bank’ account.
5 How is an ecosystem a system? What are the primary parts that make up the storages in this system?What is the flows in this system?Why is it important to an ecosystem to have all of these parts?What would happen if these parts were missing or broken?What inputs & outputs do each of these components contribute to the system?
6 2.5.1 Explain the role of producers, consumers and decomposers in the ecosystem. Energy flows through ecosystems as organisms capture and store energy, then transfer it to organisms that eat them.These organisms are grouped into trophic levels...ProducersConsumersDecomposersRelease nutrients back into the soilConvert light energy into chemical energyProvide food for the base of the food chain/webRelease oxygen into the atmospherePass energy from one organism to anotherRelease nutrients back into the soil
8 Trophic Levels: Route of energy flow food web - pyramid of numbers Tertiaryconsumers10 JSecondaryconsumers100 Jfood chainPrimaryconsumers1,000 Jfood webPrimaryproducers10,000 J1,000,000 J of sunlight- pyramid of numbers
9 Where does the energy go? Plant materialeaten by caterpillar200 JFigure An idealized pyramid of net production67 JCellularrespiration100 JFeces33 JGrowth (new biomass)
10 PRODUCERSWhat organisms are capable of trapping the energy of sunlight for conversion into the chemical energy or organic food?PlantsAlgaeSome BacteriaThese organisms are collectively referred to as producers. They provide food for themselves and for virtually all other organisms.
11 Chloroplasts (containing chlorophyll) – this is needed for photosynthesis Cell wall – made of cellulose which strengthens the cellCytoplasm – Chemical reactions happen hereCell membrane – controls what comes in and outLarge vacuole – stores water, supports cellNucleus – controls what the cell does and stores information
12 SUNLIGHT CHLOROPHYLL WATER CARBON DIOXIDE Four things are needed for photosynthesis:SUNLIGHTSpecific wavelengths of light gives the plant energyCHLOROPHYLLThe green stuff where the chemical reactions happenWATERTravels up from the rootsCARBON DIOXIDEEnters the leaf through small holes on the underneath
15 CELLULAR RESPIRATIONTransformation of chemical energy in food into chemical energy cells can use: ATPThese reactions proceed the same way in plants and animals. Process is called cellular respirationOccurs in the mitochondria of plant or animal cellsOverall Reaction:C6H12O6 + 6O2 → 6CO2 + 6H2O
18 Biogeochemical Cycles Nutrients exist in stores of chemical elementsFOUR main reservoirs where these nutrients exist are:1) Atmosphere – carbon (C) in carbon dioxide (CO2), nitrogen (N) in atmospheric nitrogen (N2)2) Lithosphere - the rocks – phosphates (PO4), calcium in calcium carbonate, potassium in feldspar3) Hydrosphere - the water (H2O) of oceans, lakes, streams and soil - nitrogen (N) in dissolved nitrate, (NO3) carbon (C) in carbonic acid (H2CO3)
19 Living Organisms and Nutrient Cycles Living organisms are a reservoir (stores) in which carbon exists in carbohydrates (mainly cellulose) and fats, nitrogen in protein, and phosphorus in ATP
20 In studying cycling of water, carbon, nitrogen, and other chemicals, ecologists focus on four factors:Biological importance of each chemicalMajor reservoirs (stores) for each chemicalForms in which each chemical is available or used by organismsKey processes driving movement of each chemical through its cycle
21 The Water Cycle Water (H2O) is essential to all organisms 97% of the biosphere’s water is stored in the oceans, 2% is in glaciers and polar ice caps, and 1% is in lakes, rivers, and groundwaterWater moves by the processes of evaporation, transpiration, condensation, precipitation, and movement through surface and groundwater (transfers)
22 The Carbon CycleCarbon-based organic molecules are essential to all organismsCarbon stores include fossil fuels, soils and sediments, solutes in oceans, plant and animal biomass, and the atmosphereCO2 is taken up via photosynthesis and released via respirationVolcanoes and the burning of fossil fuels contribute CO2 to the atmosphere
23 Carbon Cycle1. Stores – atmosphere (as CO2), fossil fuels (oil, coal), durable organic materials (for example: cellulose).2. Inputs – plants use CO2 in photosynthesis; animals consume plants.3. Outputs – plants and animals release CO2 through respiration and decomposition; CO2 is released as wood and fossil fuels are burned.
25 The Nitrogen CycleNitrogen is a component of amino acids, proteins, and nucleic acidsThe main store of nitrogen is the atmosphere (N2) 78%N2 is converted to NH3 via nitrogen-fixing bacteriaN2 is converted to NO3− via lighteningOrganic nitrogen is decomposed to (ammonium) NH4+ by ammonification, and NH4+ is decomposed to (nitrate) NO3– by nitrifying bacteria; NH4+ and NO3– assimilated by plantsDenitrifying bacteria convert NO3– back to N2NOTE: N2, NO, N20, and NO2 are not usable by plants (all but N2 contribute to smog.)NO3- (nitrate) and NH4+ (ammonium) forms of nitrogen are biologically usable
26 Nitrogen Cycle: Key Points Nitrogen is in the atmosphere as N2 (78%)N2 is an inert gas and cannot be used by plants or animalsN2 can be converted to a usable form viaLighteningN-fixing plants and cyanobacteriaIndustrial process (energy intensive)Nitrogen limits plant growthNitrogen is easily lost from biological systems
27 List Some Examples of Transformations Carbon cycle: Organic compounds to CO2 (processes: respiration, decomposition, or fire)Carbon cycle: CO2 to organic compounds (process: photosynthesis)Nitrogen cycle: N2 to NO3 (atmospheric nitrogen to plant utilizable nitrate) (process: N-fixation)Nitrogen cycle: N2 to NH3 (plant utilizable ammonia) (process: Haber-Bosch Industrial N-fixation)Water cycle: Liquid water to water vapor (process: evaporation and evapo-transpiration)Water cycle: Water vapor to liquid water (process: condensation)