Bài giảng Environmental Sciences - Chapter 3 Ecosystems How they work

EcosystemsHow they workChapter 3Biosphere IIPurpose: recreate conditions of Earth (Biosphere I) * to understand our world better * space travel5 acres in Arizona, 4000 species, 10 humans * problem: 02 + CO2 were absorbed by concrete * ants and cockroaches took over Recycle or DieThis means that we have a limited supply of raw materials (formation of the earth)All matter is recycled through the lithosphere, hydrosphere, and atmosphere.Nothing is created nothing is destroyedAll stable ecosystems recycle matter and get energy from the sunPhysicsEnergy is measured in caloriesCalorie – amount of heat needed to raise 1 gram of water 1 degree Celsius.Kilocalorie = 1,000 calories 1st law of thermodynamicsEnergy cannot be created nor destroyed, only change forms (light to chemical)2nd law of thermodynamicsEnergy transformation increases disorder (entropy) of the universe. Heat is the lowest grade of energy.Chemistry Atoms – basic units of matterElectronProtonNeutronChemical bonds - how atoms are held togetherIonicCovalentMolecule/compound – two or more atoms bonded togetherpH scaleBase/alkalineAcidKnow these elementsTop 6 most abundant elements in living things (not in order) * NCHOPSTop 8 elements in the earths crust (in order) * O, Si, Al, Fe (iron), Ca, Na (sodium), P, MgOnly silly apes in college study past midnight.Organic CompoundsC-C bonds and/or C-H bondsThey can be natural or syntheticNatural: compounds that make up living systemsSynthetic: man-made compounds78% N221% O2<1% Argon0.04% CO2 Major gases in the troposphere:PhotosynthesisVery inefficient (Only 1% of the energy from the sun is used)Chlorophyll – absorbs light to drive photosynthesisPhotosynthesis Continued..Plants use glucose to:Construct other moleculesBuild their cell wallStore energySource of energyBuilding blocks of living thingsPhospholipidsSteroidsProteins Chains of amino acidsMusclesEnzymesNucleic acidsChain of nucleotidesDeoxyribonucleic acidRibonucleic acidNitrogen cycleMain reserve in the atmosphereLiving things must get N from ammonium (NH4) or nitrate (NO3)N from the atmo must be fixed Change N2 into ammonium or nitrateRhizobium (bacteria living in roots of legumes) fig 3-10IndustrialLightningBurning fossil fuelsPhosphorus cycleNo gas phase, only solid and liquidMan-made fertilizers contain organic phosphatesBecause P is a limiting factor in aquatic systems, it leads to eutrophicationThe rain forest is very good at recycling P, except when we cut it downCarbon cycleWe will play the carbon cycle gameBig hint = photosynthesis!elementMain nonliving reservoirMain living reservoirOther nonliving reservoirHuman-induced problemCarbonCAtmoCO2Carbohydrates (CH2O)nAnd all organic moleculesHydroCarbonate (CO3-2)Bicarbonate (HCO3-)Litho minerals Global warmingCarbon from fossil fuels underground are burned and released into the air as CO2NitrogenNAtmoN2Proteins and other N- containing organic moleculesHydroAmmoniumNH4+NitrateNO3-Nitrite NO2-EutrophicationFertilizers contain human-made nitrates that end up in the waterPhos-phorousPLithorocks as PO4-3*no gas phaseDNAATPphospholipidsHydroPhosphatePO4-3EutrophicationFertilizers contain human-made phosphates that end up in the waterCutting down rainforest stops recycling of P