生态学英文版

EcologyP.19Ecology（生!W擘）IntroductionEcology--Conceptoftheecosystem-Thebiosphereandbiomes?Bioshpere生物圈oThepartoftheEarthanditsatmosphereinhabitedbylifeiscalledbiosphereoThus,theoceans,landsurfaceandlowerpartsoftheatmosphereallformpartsofthebiosphere.?Biome生物群落oThebiospherecanbedividedintobiomeswhicharelinkedbyacommontypeofvegetation.oForests,desertsandgrasslandsaretheexamplesofbiomes.Eachbiomeconsistsofmanyecosystemsinwhichcommunitieshaveadaptedtodifferencesinclimate,soil,andotherenvironmentalfactorsthroughoutthebiome.A.TheEcosystem生Ii系统Anecosystemisdefinedasacomplexformedbythelivingcommunityofdifferentspeciesinteractingwithoneanotherandwiththeirnon-livingenvironmentofmatterandenergytoresultinastableandself-sustainablesystem.Componentsofanecosystem:livingcommunityandnon-livingcomponent?Apopulation槿群consistsofallmembersofthesamespeciesoccupyingagivenareaatthesametime.?Acommunity群落consistsofPopulationsofallthedifferentspeciesinteractingwithoneanother?Ahabitat生境isasmallspecificplacewhereanorganismlives.-typesofhabitats:terrestrialhabitat----forest,aquatichabitat——freshwater:pond,lake,reservoir,?marine:sandyshore,muddyshore,Ahabitatcandivideintonumerousmicrohabitats/」、生境,eachwith\nEcologyP.19?Theniche生魅位ofaspeciesdescribestheroleofspecificspeciesinitscommunity.Nichesaresometimesdistinguishedfromhabitatsbysayingthahehabitatofanorganismisitsaddress,whileitsnicheisitsroleinthecommunity.e.g.onatree:caterpillars(feedonleaves),beetles(burrowintotrunk)theyliveonsameplacebutfunctionallytheyoccupydifferentniches.?Thebiotic(living)factors生物的arecomprisedbyalllivingorganismswithintheecosystem.?Theabiotic(non-living)非生物的factorsaremainlydividedintosoil,waterandclimate.oWaterisessentialforalllivingorganismsinthesoilandenterslivingcellsbyosmosis.oSoilsvaryintheircontentofclay,silt,sandandgravel.Thecompositionofsoildeterminesthesoiltexture,porosity,water-retainingcapacityandoxygencontent.Soilcontainsamixtureoforganicandinorganicnutrients(humusandminerals).oClimateincludesenvironmentalvariablessuchaslight,temperature,moisture,salinityandwind.ThesefactorsareimportantindeterminingthetypesoflivingorganismsintheecosystemA.EnergyflowandnutrientcyclingintheecosystemI)Transferofenergy(manyapproaches,accordingtofunctionsinecosystem)FoodchainAlinearsequenceoforganismsshowingapathwayoffoodconsumptionfromproducersthroughaseriesofconsumers.Inthisseries,anorganismfeedsontheonebeforeitandformsthefoodoftheorganismafterit.Foodchainsareshort(4-5levels)becauseonly10-20%ofenergyistransferredtothenextstage.Eachstageinfoodchain=Trophiclevels?Thenumberofstepsbywhichtheorganismsobtaintheirenergyfromplantsinafoodchain.---theproducersalwaysatthefirsttrophiclevel.Producersconsumersconsumersconsumers►decomposers►a)Producers:autotrophs自U--photosynthetice.g.greenplant,photosyntheticbacteria,chemosyntheticbacteriae.g.nitrifyingbacteria,\nEcologyP.19baseoffoodchainandfoodweb.N.B.:Phytoplanktons,whicharemicroorganisms,areimportantproducersfloatingontheupperlayersoflakesorocean.Theyareunicellularorganismswhichalsocontainchloroplaststocarryoutphotosynthesisjustliketheterrestrialplants.a)Primaryconsumers:herbivoreswhichfeedonplantse.g.pondsnails,insectlarvae.b)Secondaryconsumers:carnivoreswhichfeedonprimaryconsumerse.g.smallfish.c)Tertiaryconsumers:largercarnivoreswhichfeedonsecondaryconsumerse.g.largefishd)Decomposers:mainly,分解者decomposedeadbodiesofplantsandanimalsintosimplercompoundswhichcanthenbeabsorbedbygreenplantsagain,importantinrecyclingofnutrientsandclearingupdeadbodiesandexcretoryremains.e)Detritivores:consumethelossesfromthefoodchain,ordeadorganicmatterdetached食腐®CS&物fromdeadbodiesorexcreta(detritus),movementofenergyandmatterinacontinuousmanner,thereforehardtodefinetrophiclevel,mainlybacteria,fungi,protozoans,insects,mitesandsomesmallvertebrates,detritusddetritivoresccarnivoresandherbivoresImportances:detritivoresbreakdowncomplexcompoundstosimplermolecules,thereforespeedingupdecompositionofdeadbodiesandexcretoryremainsbybreakingupdetritusintosmallpiecesthusincreasingthesurfaceareaavailableformicrobialaction,addingproteinsandmicroorganismsontothesoilbytheirfaecesf)otherdefinitionsystem:Producei—hherbivoresccarnivores—topcarnivores(prey)(prey/predator)(predator)Someanimalsmayactasbothherbivoreandcarnivore:omnivore\nEcologyP.19AUTOTROPHHERBIWREPRIMfiRVPRIMARYPRODUCERCONSUMERPRIMARVCARNIMORESECONDflRVCONSUMERSECONDARYCARNIUORETERTIRRVCONSUrtERFoodweb-2ormoreinterconnectingfoodchains,eachorganismmayhavedifferenttrophicleve管看屈indifferentfoodchainwithinafoodweb.-examplesofwoodlandandfreshwaterhabitat(refertoanytextbook)Exampleoffoodweb:MarshKillerUJhaleMarshUegetation(includesmianyspeciesofsedges,grasses,bullrushes,algaeTetcjII)LeveloforganizationArrangethefollowingecologicaltermsinorder:biosphere,community,population,organ,organism,biome,cellSpecies:III)EcologicalenergeticsProduction:amountofmaterialswhichaccumulateoverafixedamountoftime.Topcarnivores\nEcologyP.19CarnivoresdecomposersHerbivoresGreenplantsN.B.Muchofthesolarenergyreachingtheplantislostbyreflectionandphotosyntheticinefficiency.Usefulterms:?Biologicalproductivity生物生力istherateatwhichbiomassisproducedbyanecosystem.Ithastwocomponents:oPrimaryproductivity初级生力,theproductionofneworganicmatterbygreenplants(autotrophs).oSecondaryproductivity次级生力,theproductionofneworganicmatterbyconsumers(heterotrophs).?Bothofthesecanbedividedintogrossprimaryproductivityandnetprimaryproductivity.?Grossprimaryproductivity(GPP)余恩初级生力oThetotalamountoforgaincmatterproducedbygreenplantsinunitareaandperunittime.GPPdoesnotrepresenttheactualamountoffoodpotentiallyavailabletoheterotrophsbecausesomeoftheorganicmattersareusedtomeetplant'srespirationandmetabolism.?Netprimaryproductivity(NPP)浮初级生力oThetotalamountoforganicmatteroftheorganismafterrespirationandmetabolismhavebeenfueled.Thereforeitrepresentsthepotentialfoodenergyavailabletoheterotrophs.Netsecondaryproductivity:N.B.:Usually,planthas10%averageefficiencyofenergytransferwhileanimalhas20%,explainwhy?II)Pyramids1)Pyramidofnumber(abundance)数目塔-adiagramrepresentingtheprogressivedropinnumbersofindividualsateachsuccessivetrophiclevel,usuallyuprighte.g.\nEcologyP.19-sometimesmaybeinvertede.g.-Notagoodrepresentation:1)Pyramidofbiomass(unit:g/m2)生物量塔-Biomass?-betterideaaboutthequantityofmaterialsineachtrophiclevelrequiredtosupportthoselevelaboveit,totalamountoforganicmatterislargestatthebaseofafoodchain,-normalshape:upright,rarecase:inverted,why?Reason----producerlevelhasrapidturnoverratee.g.phytoplanktonsmayhavesmallerbiomassthantruebuthavehigherproductivity,thereforeinthiscase,harvestanimalisbetterthanharvestproducer,2)Pyramidofenergy能量塔(productivity)(Unit:g/m2/day,month,year)-thebestbecause:a)ittakesintoaccounttherateofproduction,thatistheimefactor.b)noinvertedpyramid---alwaysupright,c)importanceofsolarenergycanbestressed.Criticismofallpyramids:-inafoodweb,manyorganismscannotbeplacedinONEsuitabletrophiclevel.-somestillinverted,why??\nEcologyP.19CyclingofNutrientsinEcosystemsA.CarbonCycle?Carbonisanessentialbuildingelementforallorganiccompounds.ThecyclicflowofcarboninNatureisknownasthecarboncycle.oInNature,themostabundantsourceofcarbonexistsasarbondioxidefreeintheatmosphereanddissolveinoceans.oDuringphotosynthesisproducersmakeuseoflightenergytoconvertcarbondioxideintoorganiccarboncompoundsintheirbodiesoWhenproducersareeaten,theorganiccarboncompoundsintheirbodiesarepassedontotheconsumers.oInthebodiesofbothproducersandconsumers,partoftheorganiccarboncompoundsisbrokendownintocarbondioxideduringrespirationandbringbacktotheatmosphereandoceans.oWhentheorganismsdie,acertainamountoforganiccarboncompoundsislockedupinthedeadbodies.oGenerallythedeadbodiesundergodecomposition.Theorganiccarboncompoundsareconvertedtocarbondioxideandliberatedduringthrespirationofdecomposers.oSometimes,thedeadbodiesmaybecomfossilfuels.Insuchacase,thecarbondioxidecanonlybereleasedwhenthefuelsareburnt.Theprocessiscalledcombustion.CarbonCycleDecomposition/jntheatmosphere*anddifisoh/edCoiTibusticnDeathExcretion/deathRespirationDeath：butdecayispreventedDeath,butdecayisPlants\nEcologyP.19B.NitrogenCycle?Nitrogenisanessentialelementinthesynthesisofproteins.ThecyclicflowofnitrogeninNatureisknownasthenitrogen.oDuringaprocesscallednitrogenfixation,atmosphericnitrogenischangedtonitratesinthesoil.Thisprocessiscarriedoutbyagroupofbacteriacallednitrogen-fixingbacteria.固氮余田菌oDuringlightening,atmosphericnitrogencanalsobechangedtonitrates.oThenitrogeninthesoilisabsorbedbyproducersinionicformsandconvertedtoorganicnitrogenouscompoundsintheirbody.oWhenproducersareeaten,theorganicnitrogenouscompoundsintheirbodiesarepassedontotheconsumers.oSomeofthenitrogenintheconsumers'bodiesarelostaesxcretoryproducts.oWhentheorganismsdie,acertainamountoforganicnitrogenislockedupinthedeadbodies.oTheorganicnitrogenintheexcretoryproductsanddeadbodiesisbrokendownintoammoniumcompoundsbyagroupofbacteriacalledputrefyingbacteria.Theprocessiscalledputrefaction.腐败作用oTheammoniumcompoundsarechangedstepwisetonitratesbnyitrifyingbacteria.Theprocessiscallednitrification.oAprocesscalleddenitrificationchangessomeoftheinorganicnitrogencompoundsinthesoilchangedtonitrogengasbytheso-calleddenitrifyingbacteria.Thenitrogengasisreturnedtotheatmosphere.\nEcologyP.19Nitrites(NOJhtitri^ringbadenae.g.NdrobacterAb5ooption口『rocia"怕的巾■SpiianUNidifyngbaclerlaQ.g.N市gGEcnasNlirogan/fixingb£cteiiaDenilrlfyingbacteriae.g.Pseifdcgn醺5:君忘Phizobdin(symbiallcjJF启电dingd&nitriticans:Azotoi^ct6r(hee-hving);and-/:dtgest^nUghtnngXJ3.Ammaniunionmp&unds(HI］：」AtmosphericnitrogenPretflinih$animalsChorrtolGom^inalior)Industrial(Haber)piocessPulrefyngbacteriaDeathF.irefyingbnctenatxcrtilionReference:ChineseversionofCarbonandNitrogencycleCarbonCycle:NitrogencycleEcologyP.19EcologyP.19NitrogenCycle:\nEcologyP.19硝化iffl菌，例InterdependenceoforganismsBasicinteractiontypes0noreaction+positiveinfluence:benefit-negativea)+0:b)++:c)+-:d)+-:e)--:A)Positiveinteractions1)Commensalism片行共生Differentspeciesoforganismslivingtogether,withonlyonegettingbenefitswhiletheothergetnoharm,e.g.thebarnacles藤1ftattachthemselvestotheshellsofhermitcrabs.Theyobtainnourishmentfromthefoodleftbythecrabafterithaseaten,andthecrabcanhelpthemescapefromdanger.\nEcologyP.191)Mutualism(symbiosis)互利共生Differentspecieslivingtogetherthatarebeneficialtoboth,e.gl.ichenswhicharetheassociationoffungiandalgae.Thealgaisprotectedfromhighlightintensityanddesiccationbythefungi.Moreover,thefungiareconstantlysuppliedwithorganicfoodsubstancesbythealgaefromphotosynthesis.Otherexample:symbioticbacteriaandrabbits.A)Negativeinteraction1)Predation(+-):twoindividualsinwhichonepreysontheotherwhiletheotherisbeingeatene.g.foxesandrabbits.N.B.predatorsregulatingthepreypopulation,i.e.Biologicalcontrol,thereforebenefically.2)Parasitism(+-):Theparasiteobtainsfoodorshelterfromthehost.Itcanbefurtherdividedintoectoparasites,whichliveontheoutersurfaceofahost,andendoparasites,whichlivewithinahost.e.g.tapewormfoundinhumandigestivesystemobtainnourishmentfromthehumanhost.N.B.theparasitemustnotkillthehostorelseitdestroysitself.3)Competition(--):a)Interspecificorintraspecific:whichoneismoreserious?e.g.barnaclesandoysterscompeteforspaceandfoodb)Twotypes:(Scramble孚U):(Contest):c)Effects-onplant:changesingrowthrate(competitionfornutrientsorlight),extinctionoflesssuccessfulspecies,-onanimal:i)aggression,ii)territory,iii)emigration,iv)increaseindeathrate,v)predation.d)Evolutionarysignificance:\nEcologyP.191)eliminatelesswell-adaptedindividuals,thereforegradualimprovementofspecies,2)givesrisetoadaptiveradiation1.e.fillingofmorediverseecologicalnichesbyanoriginalspecies,thereforecompetitioninfield--3)successincompetitiondependsonenvironmentalconditions,conditionsmayfavouronespeciesatonetime,andadifferentoneatsomeothertime,thereforedifferentspeciesmayfluctuateinnumber.\nEcologyP.19Succession演替Successionisdefinedasaseriesofchangesinthestructureandcompositionofacommunityfromthepioneercommunitytotheclimaxcommunityoveraperiodoftime.Primarysuccession:Invasionandcolonizationofbarerock,onlyalgaeandlichenscaninvadeandcolonizethearea(insufficientsoilandnutrientsfortreesandshrubs)--firstcolonizers.AccumulationofdeadanddecomposingorganismsandtheerosionofrockbyweatheringColonizationbylargerplantspeciessuchasmossesorferns\zThedeathanddecompositionoftheseplantsfurtherenrichthesoil\7Colonizationbyseed-bearingplants,includinggrasses,shrubsandtrees.Secondarysuccession:Whenthecompletelycolonizedsurfacehasbeeninfluencedbylivingorganismsipman)orenvironmentalfactorsfire),secondarysuccessionoccurs--resultinmesophytesdominantcausesofsuccession:changesinenvironmentofapondIexistingcommunitiesnolongeradaptedInewspeciestakeoverClimaxcommunity:IB趣群落Thefinalstableandself-perpetuatingcommunitydevelopedafternumberofsuccessionalcommunities,canresistenvironmentalchangesandcompetition,anditisthemostproductivecommunitythattheenvironmentcansustain.Characteristics1)determinedbyhabitatfactors,2)interactionresultsinastablebalancedunit,3)anaturalcommunity:selfsufficientandself-maintaining,4)speciescompositionofanaturalcommunityistheresultofnaturalselection.Adaptationsoforganismstotheenvironmenta)Definition:characteristicofanorganismwithdefinitevalueinallowingittoexistunderconditionofits\nEcologyP.19habitatsinordertoensureitscontinuity,allowtheorganismtomakeuseofenvironmentalresourcesorprotectitagainstadverseconditions.a)Typesofadaptation:a)morphological,b)physiological,c)behaviouralb)Significanceofadaptation:-naturalselectioneliminatestheonenotadapted,thereforetheadaptedarefavouredi.e.'survivaloffittest',-abilityofspeciestoremaininexistencedependson:i)ii)ExamplesofadaptationsReproductiona)Viviparous胎生droppersofKandelia水肇仔:-dominantinmangrovesinH.K.,-seedlings(fruits)exhibitvivipary--theydevelopwhilestillattachedtotheparentplants,forming'droppers'whichfallintothewaterandfloataway,comingtorestinanuprightpositionasthetiderecedes,-thereforeadapttoi)unstablesubstratum,11)anaerobicmud,iii)salinecondition.Survivala)HoldfastofSargassum(brownalgae),-liveontheintertidalzoneofmarinehabitat,-developapowerfulholdfastwhichisaflatteneddisccapableofadheringstronglytoalmostanysolidsubstratum.b)ShapedleavesoPinus:-developsuccessfullyasanevergreenplantinrelativelypoor,drysoil,-darkgreen'needle'leafwithsunkenstomata,-eachhastheshinylookassociatedwithathickcuticleandisgroovedalongitslength,-smallbrownscaleleavesforprotectionofbudsanddwarfedshoot.NotesonfieldstudiesEnvironment-thesurroundings\nEcologyP.19-i.e.thesumtotalofexternalinfluencesactingonanorganismorcommunity.A)Abiotic(physical):-----climaticsoil(edaphic)topographica)ClimaticTemperature:-biochemicalprocesses:mostlifeexistwithin0—600C-physiologicaleffects(breeding),-adaptations:i)behavioral—ii)structural——Rainfall:-needformanyfunctions(germination,locomotion,transport,metabolism,osmoregulation),-presenceorabsenceofwatercausesmanyadaptations:inplants:inanimals:-governsdistributionoftropicalrainforest,temperateforest,-Light:-threefactors:-photosynthesis:foodproduction,flowering(photoperiodism),transpiration,behaviour;breedingcycles,tropismsandnasticresponse,controlzonationHumidity-isrelatedtowind,rainfallandtemperature,-transpirationrate,-behaviourofanimalse.g.rockyshoreanimalsseekdampplacewhenexposed,Wind\nEcologyP.19-transpiration,-affectsmodeofgrowthofvegetation:e.g.mechanicaldamage:stuntingandshearing,defoliation,distortion-dispersalofseeds,fruitsandspores,pollinationb)Soil(Edaphic)factors-soilfactori.e.factorswhichdescribetheconditionsofthesoilorsubstratum,-refertonotesofsoil.c)Topographicfactors-positionofanareainrelationtothesurroundingcountry:i)altitude,ii)contour,iii)direction.B)BioticfactorsEffects1)Plant:sourceoffood---primaryproducer2)Interaction:refertonotestaughtbefore3)Pollinationanddispersalofseedandfoodbyanimals4)Protectiveadaptation:a):protectivecoloration,b):manyanimalsresembleplantsinshapee.g.stickinsectsorresembleotherharmfulanimalspecies,thereforeobtainbenefitsfromthisresemblance.5)Man'seffectonenvironment:farming,pollution-importanttopic,discusslaterMethodsofsamplingonarea:StudythedistributionandabundanceoforganismsA)Transects协察Definition:alinecuttingthroughanarea,usedtosurveyvegetationorfaunaofthearea.Typesoftransects\nEcologyP.191)LinetransectW®:-linearsurveyofplantsandanimalsthroughanarea,changeinlevelisnotrecorded.一selectatypicalstretchofareasofinterestinthehabitat,一laidaropeonground,e.g.10meter(fixedatthe2end),一checkplantsandanimalstouchingthelineevery0.5-1meter,一recordabundanceanddistributionofspeciestouchingtherope,一datagraphed(histograms/kitediagrams/etc.)andanalysed.2)Profiletransects剖面Sfe®:-adiagramshowstheprofile,i.e.changeinlevel,alongagivendirection,-vegetationandanimalsarealsoindicatedalongit,showpossiblechangesinvegetabletype,-howtomeasurethelevel?3)Belttransect檬带:-surveyofastripthroughanarea,usually2parallellinesonemetreapart,-usuallyrecordwithquadrat.Presentationofdata1)2)3)B)Quadrat檬方Definition:ansquareofknowndimension,usedtosamplevegetationoranimals,recordtheabundanceanddistributionofspeciesrecorded.Thetoolused:quadratframe一randomoralongatransectbelttransect),一countthenumberofeachspeciesoccurringinthequadrat/estimatethepercentagecoverageofeachspeciesinthequadrat,一forrandomsampling:repeatanumberoftimestogettheaverage,\nEcologyP.19一forsystematicsampling:belttransect---repeatalongthetransect,一Presentthedata(1)Maybeusedtomeasure1)seasonalchange2)zonation3)populationnumberPointquadrat:amethodbywhichfinepointedwiresareloweredontothevegetationinsidethequadrattomeasurerelativeabundance.e.g.frequencyofplantAZonation成带壬同象-characteristicdistributionoforganismsintozonesorstrata(verticalzonatione.g.forest).Discussion:Whatarethelimitationsofusingtransectandquadrat?Exampleofhabitat---Rockyshore岩岸Generallayout:\nEcologyP.19Factorsonrockyshore1)tidalflow,2)waveaction,3)substratum基/W,4)sunlight(illumination),5)rainfall,humidity,6)wind,7)salinity(rockpool)Problemsfaced1)2)3)4)LowershoreexcretionbydiffusionandexcreteammoniaGeneraladaptationonrockyshoreUppershore1)lungbreathers2)complexexcretoryorgansandexcreteuricacidsEcologyP.19EcologyP.193)mobile,cryptic,thickshellssedimentary,non-cryptic,thinEcologyP.19EcologyP.19Typicaldistributionoffloraandfauna