环境科学复习要点-师兄版.doc

环境科学复习要点-师兄版.doc

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CHAPTERONE：

EnvironmentalInterrelationships

Environment:

thesurroundingconditionsthataffectpeopleandotherorganism.Inabroaderdefinition,environmentiseverythingthataffectsanorganismduringitslifetime.

环境：

与某一中心事物有关的周围事物，就是这个中心事物的环境。

EnvironmentalScience:

isaninterdisciplinaryareaofstudythatincludesbothappliedandtheoreticalaspectsofhumanimpactontheworld.

Thefieldofenvironmentalscienceinvolvesanunderstandingofscientificprinciples,economicinfluences,andpoliticalaction.Environmentdecisionsofentinvolvecompromise.（fig.1.1）

InternationalOrganization

Inordertosolvethecommonenvironmentalissues,severalinternationalorganizationswerefounded,andseveralinternationalconventionswereestablished.

Theinternationaljointcommission（1909）

boundarywaterstreaty

Theunitednationsconferenceonenvironmentanddevelopment（1992,UNCED）

sustainabledevelopmentandbiodiversityAgenda21

TheKyotoconferenceonclimatechange（1997）

theKyotoprotocol

TheUnitedNationsEducational,Scientific,andCulturalOrganization（UNESCO）

supportedmanyenvironmentalprograms.

Anecosystem：

isaregioninwhichtheorganismsandthephysicalenvironmentforminteractingunit.

Forsolvingregionalenvironmentalissues,it’sveryusefultoadoptecosystemapproach.

Noregionisfreeofenvironmentalconcerns.

RegionalvignettesinAmerica

TheWidenessNorth

characteristic:

wilderness--areaswithminimalhumaninfluence.

Muchofthislandisownedbygovernments,notbyindividuals,sogovernmentpolicieshavealargeeffectonwhathappensintheseregions.

TheAgriculturalMiddle

characteristic:

intensiveagriculture.

Original,naturalecosystemshavebeenreplacedbymanagedagriculturalenterprise.

nonpointpollutionsources（pollutionthatdoesnothaveaneasilyidentifiedpointoforigin）.

TheDryWest

characteristic:

inadequaterainfall,landisofloweconomicvalue,mostofitisstillthepropertyofgovernment.

Populationdensityislow,muchofthelandhasawildernesscharacter.

TheForestedWest

characteristic:

sufficientrainfall,coniferousforestsarethedominantvegetation.

Sincemostoftheseareasarenotsuitableforfarmland,theyhavebeenmaintainedasforestswithsomegrazingactivityinthemoreopenforests.timbercutting.

Environmentalinterestsareconcernedabouttheconsequencesloggingwouldhaveonorganismsthatrequiremature,old-growthforestsfortheirsurvival.

TheGreatLakesandIndustrialNortheast

characteristic:

dominatedbylargemetropolitancomplexesthatgeneratesocialandresourceneedsthataredifficulttosatisfy.

Amajorconcernaboutthesepollutantsisthattheybioaccumulateinthefoodchain.

Theirmajorenvironmentalprioritiesarecleaningupcontaminatedsites,providingmoreparksandrecreationfacilities,reducingairandwaterpollution,andimprovingtransportation.

TheDiverseSouth

characteristic:

diverse.

TheSouthisamicrocosmofalltheregionspreviouslydiscussed.ThepetrochemicalindustrydominatestheeconomiesofTexasandLouisiana,andforestryandagriculturearesignificantelementsoftheeconomyinotherpartsoftheregion.Majormetropolitanareasthrive,andmuchoftheareaislinkedtothecoasteitherdirectlyorbytheMississippiRiveranditstributaries.TheenvironmentalissuesfacedintheSouthareasdiverseasthoseinalltheotherregions.

PovertyhasbeenaprobleminmanyareasoftheSouth.Thiscreatesaclimatethatencouragesstateandlocalgovernmentstoacceptindustrialdevelopmentattheexpenseofothervalues.Often,jobsaremoreimportantthantheenvironmentalconsequencesofthejobs;low-payingjobsarebetterthannojobs.

Environmentalproblemsarepeopleproblems.

Summary

Artificialpoliticalboundariescreatedifficultiesinmanagingenvironmentalproblemsbecausemostenvironmentalunits,ecosystems,donotcoincidewithpoliticalboundaries.Therefore,aregionalapproachtosolvingenvironmentalproblems,onethatincorporatesnaturalgeographicunits,isideal.Eachregionoftheworldhascertainenvironmentalissuesthatareofprimaryconcernbecauseofthemixofpopulation,resourceusepatterns,andculture.

Environmentalproblemsbecomeissueswhensomeonefindsasituationoffensive.Thisinevitablyleadstoaconfrontationbetweengroupsthathavedifferentviewsonwhatconstitutesanenvironmentalproblem.Manysocial,economic,ethical,andscientificinputsshapeaperson'sopinions.Theprocessofenvironmentaldecisionmakingmusttakealloftheseinputsintoaccountandarriveatanacceptablecompromise.Environmentalproblemsarepeopleproblems.Theyoccurbecausetheusesofnaturalresources,whichsomepeoplefeelarejustified,resultinadiminishedenvironmentforothersintheregion.Environmentalproblemsaredefinedbythepersonwhoperceivestheproblem.Whenperceptionsdiffer,conflictoccurs.Environmentaldecisionsinevitablyinvolveeconomicconsiderationsbecausesomeoneisreceivingvaluefromtheresourcesbeingusedorsomeoneperceivesaneconomiclossbecauseausehasbeenwithdrawn.

CompromiseistheonlywaytoresolvetheEnvironmentalconflicts

CHAPTERTHREE:

KindsofEcosystemsandCommunities

Succession

Thecommunitiesproceedthroughaseriesofrecognizable,predictablechangesinstructureovertimeiscalledsuccession.

Primarysuccessionisasuccessionalprogressionthatbeginswithatotallackoforganismsandbaremineralsurfacesorwater.TerrestrialPrimarySuccessionAquaticPrimarySuccession

SecondarySuccession

Anoriginalcommunityisdestroyedandreplacedbyannewcommunity,thisprogressiscalledsecondarysuccession.

Community:

isanassemblageofalltheinteractingpopulationsofdifferentspeciesoforganismsinanarea.

Climaxcommunity:

Therelativelystable,long-lastingcommunityiscalledclimaxcommunity

LichenApioneerorganism

Biomes:

MajorTypesofTerrestrialClimaxCommunities

Theeffectofelevationonclimateandvegetation

Deserts:

Alackofwateristheprimaryfactorthatdeterminesthatanareawillbedesert.Desertsareareasthatgenerallyreceivefewerthan25centimetersofprecipitationperyear.

Grassland:

Grasslands,alsoknownasprairiesorsteppes,arewidelydistributedovertemperatepartsoftheworld.Aswithdeserts,themajorfactorthatcontributestotheestablishmentofagrasslandistheamountofavailablemoisture.Grasslandsgenerallyreceivebetween25and75centimetersofprecipitationperyear.Theseareasarewindywithhotsummersandcoldtomildwinters.

Savanna:

TropicalpartsofAfrica,SouthAmerica,andAustraliahaveextensivegrasslandsspottedwithoccasionaltreesorpatchesoftrees.Thiskindofabiomeisoftencalledasavanna.Theseareasoftheworldaretypicallytropical,with50to150centimetersofrainperyear.Therainisnotdistributedevenlythrough-outtheyear.

TropicalDryRainforest:

Manyofthetropicaldryforestshaveamonsoonclimateinwhichseveralmonthsofheavyrainfallarefollowedbyextensivedryperiodsrangingfromafewtoasmanyaseightmonths.（Seefigure6.14）therainfallmaybeaslowas50centimetersorashighas200centimeters,butsincetherainfallishighlyseasonal,manyoftheplantshavespecialadaptationsforenduringdrought.

TropicalRainforest:

TropicalrainforestsarelocatedneartheequatorinCentralandSouthAmerica,Africa,SoutheastAsia,andsomeislandsintheCaribbeanSeaandPacificOcean.（Seefigure6.15.）Thetemperatureisnormallywarmandrelativelyconstant.Thereisnofrost,anditrainsnearlyeveryday.Mostareasreceiveinexcessof200centimetersofrainperyear.Somereceive500centimetersormore.Becauseofthewarmtemperaturesandabundantrainfall,mostplantsgrowveryrapidly;however,soilsareoftenpoorinnutrientsbecausewatertendstocarryawayanynutrientsnotimmediatelytakenupbyplants.

MarineEcosystems

ThoseAquaticEcosystemsthathaveahighsaltcontentarecalledmarineecosystems.

PelagicMarineEcosystems:

Intheopenocean,manykindsoforganismsfloatsorswimactively.Crustaceans,fish,andwhalesswimactivelyastheypursuefood.Organismsthatarenotattachedtothebottomarecalledpelagicorganisms,andtheecosystemtheyareapartofiscalledapelagicecosystem.

BenthicMarineEcosystems:

Organismsthatliveontheoceanbottom,whetherattachedornot,areknownasbenthicorganisms,andthekindofecosystemofwhichtheyareapartiscalledabenthicecosystem.

Estuaries:

Anestuariesisaspecialcategoryofmarineecosystem,thatconsistofshallow,partiallyenclosedareaswherefreshwaterenterstheocean.Thesaltinessofthewaterintheestuarychangeswithtidesandtheflowofwaterfromrivers.Theorganismsthatliveherearespeciallyadaptedtothissetofphysicalconditions,andthenumberofspeciesislessthanintheoceanorinfreshwater.

FreshwaterEcosystems

Thosethathavelittledissolvedsaltarecalledfreshwaterecosystems

Freshwaterecosystemsdifferfrommarineecosystemsinseveralways.Theamountofsaltpresentismuchless,thetemperatureofthewatercanchangegreatly,thewaterisintheprocessofmovingdownhill,oxygencanoftenbeinshortsupply,andtheorganismsthatinhabitfreshwatersystemsaredifferent.

LakesandPonds:

Largelakeshavemanyofthesamecharacteristicsastheocean.Ifthelakeisdeep,thereisaeuphoticzoneatthetop.

StreamsandRivers:

thewaterisshallow,lightcanpenetrateeasilytothebottom（exceptforlargeorextremelymuddyrivers）.Evenso,itisdifficultforphotosyntheticorganismstoaccumu