AsGilbertWhite,Darwin,andothersobservedlongago,allspeciesappeartohavetheinnatecapacitytoincreasetheirnumbersfromgenerationtogeneration.Thetaskforecologistsistountangletheenvironmentaandbiologicalfactorsthatholdthisintrinsiccapacityforpopulationgrowthincheckoverthelongrun.Thegreatvarietyofdynamicbehaviorsexhibitedbydifferentpopulationmakesthistaskmoredifficult:sompopulationsremainroughlyconstantfromyeartoyear;othersexhibitregularcyclesofabundanceandscarcity;stillothersvarywildly,withoutbreaksandcrashesthatareinsomecasesplainlycorrelatedwiththeweather,andinothercasesnot.Toimposesomeorderonthiskaleidoscopeofpatterns,oneschoolofthoughtproposesdividingpopulationsintotwogroups.Theseecologistspositthattherelativelysteadypopulationshavedensity-dependentgrowthparameters;thatis,ratesofbirth,death,andmigrationwhichdependstronglyonpopulationdensity.Thehighlyvaryingpopulationshavedensity-independentgrowthparameters,withvitalratesbuffetedbyenvironmentalevents;theseratesfluctuateinawaythatiswhollyindependentofpopulationdensity.Thisdichotomyhasitsuses,butitcancauseproblemsiftakentooliterally.Foronething,nopopulationcanbedrivenentirelybydensity-independentfactorsallthetime.Nomatterhowseverelyorunpredictablybirth,death,andmigrationratesmaybefluctuatingaroundtheirlong-termaverages,iftherewerenodensity-dependenteffects,thepopulationwould,inthelongrun,eitherincreaseordecreasewithoutbound(barringamiraclebywhichgainsandlossescanceledexactly)。Putanotherway,itmaybethatonaverage99percentofalldeathsinapopulationarisefromdensity-independentcauses,andonlyonepercentfromfactorsvaryingwithdensity.Thefactorsmakinguptheonepercentmayseemunimportant,andtheircausemaybecorrespondinglyhardtodetermine.Yet,whetherrecognizedornot,theywillusuallydeterminethelong-termaveragepopulationdensity.Inordertounderstandthenatureoftheecologist’sinvestigation,wemaythinkofthedensity-dependenteffectsongrowthparametersasthesignalecologistsaretryingtoisolateandinterpret,onethattendstomakethepopulationincreasefromrelativelylowvaluesordecreasefromrelativelyhighones,whilethedensity-independenteffectsacttoproducenoiseinthepopulationdynamics.Forpopulationsthatremainrelativelyconstant,orthatoscillatearoundrepeatedcycles,thesignalcanbefairlyeasilycharacterizedanditseffectsdescribed,eventhoughthecausativebiologicalmechanismmayremainunknown.Forirregularlyfluctuatingpopulations,wearelikelytohavetoofewobservationstohaveanyhopeofextractingthesignalfromtheoverwhelmingnoise.Butitnowseemsclearthatallpopulationsareregulatedbyamixtureofdensity-dependentanddensity-independenteffectsinvaryingproportions.
1.Theauthorofthetextisprimarilyconcernedwith
[A]Discussingtwocategoriesoffactorsthatcontrolpopulationgrowthandassessingtheirrelativeimportance.
[B]Describinghowgrowthratesinnaturalpopulationsfluctuateovertimeandexplainingwhythesechangesoccur.
[C]Proposingahypothesisconcerningpopulationsizeandsuggestingwaystotestit.
[D]Posingafundamentalquestionaboutenvironmentalfactorsinpopulationgrowthandpresentingsomecurrentlyacceptedanswer.
2.Itcanbeinferredfromthetextthattheauthorconsidersthedichotomydiscussedtobe
[A]Applicableonlytoerraticallyfluctuatingpopulations.
[B]instrumental,butonlyifitslimitationsarerecognized.
[C]Dangerouslymisleadinginmostcircumstances.
[D]Acompleteandsufficientwaytoaccountforobservedphenomena.
3.tothetext,allofthefollowingbehaviorshavebeenexhibitedbydifferentpopulationsEXCEPT
[A]Roughlyconstantpopulationlevelsfromyeartoyear.
[B]Regularcyclesofincreasesanddecreasesinnumbers.
[C]Erraticincreasesinnumberscorrelatedwiththeweather.
[D]Uncheckedincreasesinnumbersovermanygenerations.
4.Thediscussionconcerningpopulationinthethirdparagraphservesprimarilyto
[A]Demonstratethedifficultiesecologistsfaceinstudyingdensity-dependentfactorslimitingpopulationgrowth.
[B]Advocatemorerigorousstudyofdensity-dependentfactorsinpopulationgrowth.
[C]Provethatthedeathratesofanypopulationareneverentirelydensity-independent.
[D]underlinetheimportanceofevensmalldensity-dependentfactorsinregulatinglong-termpopulationdensities.
5.Inthetext,theauthordoesallofthefollowingEXCEPT
[A]Citetheviewsofotherbiologists.
[B]Defineabasicproblemthatthetextaddresses.
[C]Presentconceptualcategoriesusedbyotherbiologists.
[D]Describetheresultsofaparticularstudy.
Insomecountrieswhereracialprejudiceisacute,violencehassocometobetakenforgrantedasameansofsolvingdifferences,thatitisnotevenquestioned.Therearecountrieswherethewhitemanimposeshisrulebybruteforce;therearecountrieswheretheblackmanprotestsbysettingfiretocitiesandbylootingandpillaging.Importantpeopleonbothsides,whowouldinotherrespectsappeartobereasonablemen,getupandcalmlyargueinfavorofviolence–asifitwerealegitimatesolution,likeanyother.Whatisreallyfrightening,whatreallyfillsyouwithdespair,istherealizationthatwhenitcomestothecrunch,wehavemadenoactualprogressatall.Wemaywearcollarsandtiesinsteadofwar-paint,butourinstinctsremainbasicallyunchanged.Thewholeoftherecordedhistoryofthehumanrace,thattediousdocumentationofviolence,hastaughtusabsolutelynothing.Wehavestillnotlearntthatviolenceneversolvesaproblembutmakesitmoreacute.Thesheerhorror,thebloodshed,thesufferingmeannothing.Nosolutionevercomestolightthemorningafterwhenwedismallycontemplatethesmokingruinsandwonderwhathitus.Thetrulyreasonablemenwhoknowwherethesolutionsliearefindingitharderandherdertogetahearing.Theyaredespised,mistrustedandevenpersecutedbytheirownkindbecausetheyadvocatesuchapparentlyoutrageousthingsaslawenforcement.Ifhalftheenergythatgoesintoviolentactswereputtogooduse,ifoureffortsweredirectedatcleaninguptheslumsandghettos,atimprovingliving-standardsandprovidingeducationandemploymentforall,wewouldhavegonealongwaytoarrivingatasolution.Ourstrengthissappedbyhavingtomopupthemessthatviolenceleavesinitswake.Inawell-directedeffort,itwouldnotbeimpossibletofulfilltheidealsofastablesocialprogramme.Thebenefitsthatcanbederivedfromconstructivesolutionsareeverywhereapparentintheworldaroundus.Genuineandlastingsolutionsarealwayspossible,providingweworkwithintheframeworkofthelaw.Beforewecanevenbegintocontemplatepeacefulco-existencebetweentheraces,wemustappreciateeachother'sproblems.Andtodothis,wemustlearnaboutthem:itisasimpleexerciseincommunication,inexchanginginformation."Talk,talk,talk,"theadvocatesofviolencesay,"allyoueverdoistalk,andwearenonethewiser."It'sratherlikethestoryofthefamousbarristerwhopainstakinglyexplainedhiscasetothejudge.Afterlisteningtoalengthyargumentthejudgecomplainedthatafterallthistalk,hewasnonethewiser."Possible,mylord,"thebarristerreplied,"nonethewiser,butsurelyfarbetterinformed."Knowledgeisthenecessaryprerequisitetowisdom:theknowledgethatviolencecreatestheevilsitpretendstosolve.
1.Whatisthebesttitleforthispassage?
[A]AdvocatingViolence.
[B]ViolenceCanDoNothingtoDiminishRacePrejudice.
[C]ImportantPeopleonBothSidesSeeViolenceAsaLegitimateSolution.
[D]TheInstinctsofHumanRaceAreThirstyforViolence.
2.Recordedhistoryhastaughtus
[A]violenceneversolvesanything.[B]nothing.[C]thebloodshedmeansnothing.[D]everything.
3.Itcanbeinferredthattrulyreasonablemen
[A]can'tgetahearing.
[B]arelookeddownupon.
[C]arepersecuted.
[D]Havedifficultyin
advocatinglawenforcement.
4."Hewasnonethewiser"means
[A]hewasnotatallwiseinlistening.
[B]Hewasnotatallwiserthannothingbefore.
[C]Hegainsnothingafterlistening.
[D]Hemakesnosenseoftheargument.
5.Accordingtheauthorthebestwaytosolveraceprejudiceis
[A]lawenforcement.[B]knowledge.[C]nonviolence.[D]Moppinguptheviolentmess.
WhenthepoliceofficerswhotookpartintheKingbeatingwerefirstbroughtto___________,theirlawyersusedthevideotapeasevidenceagainsttheprosecution.
Theteachers’union_________alawsuitagainstthedistrictcallingforrepairing“deplorable”schoolconditions.
___willMr.Forbesbeabletoregaincontrolofthecompany.