TPO阅读44文本答案翻译.docx

TPO阅读44文本答案翻译.docx

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TPO阅读44文本答案翻译

TPO-44

FromFishtoTerrestrialVertebrates

OneofthemostsignificantevolutionaryeventsthatoccurredonEarthwasthetransitionofwater-dwellingfishtoterrestrialtetrapods（four-limbedorganismswithbackbones）.Fishprobablyoriginatedintheoceans,andourfirstrecordsofthemareinmarinerocks.However,bytheDevonianPeriod（408millionto362millionyearsago）,theyhadradiatedintoalmostallavailableaquatichabitats,includingfreshwatersettings.Oneofthegroupswhosefossilsareespeciallycommoninrocksdepositedinfreshwateristhelobe-finnedfish.

ThefreshwaterDevonianlobe-finnedfishrhipidistiancrossopterygianisofparticularinteresttobiologistsstudyingtetrapodevolution.Thesefishlivedinriverchannelsandlakesonlargedeltas.Thedeltarocksinwhichthesefossilsarefoundarecommonlyredduetooxidizedironminerals,indicatingthatthedeltasformedinaclimatethathadalternatewetanddryperiods.Iftherewereperiodsofdrought,anyadaptationsallowingthefishtosurvivethedryconditionswouldhavebeenadvantageous.Intheserhipidistians，severalsuchadaptationsexisted.Itisknownthattheyhadlungsaswellasgillsforbreathing.Crosssectionscutthroughsomeofthefossilsrevealthatthemudfillingtheinteriorofthecarcassdifferedinconsistencyandtexturedependingonitslocationinsidethefish.Thesedifferencessuggestasadlikecavitybelowthefrontendofthegutthatcanonlybeinterpretedasalung.Gillswereundoubtedlythemainsourceofoxygenforthesefish,butthelungsservedasanauxiliarybreathingdeviceforgulpingairwhenthewaterbecameoxygendepleted,suchasduringextendedperiodsofdrought.So,thesefishhadalreadyevolvedoneoftheprimerequisitesforlivingonland:

theabilitytouseairasasourceofoxygen.

Asecondadaptationofthesefishwasinthestructureofthelobefins.Thefinswerethick,fleshy,andquitesturdy,withamedianaxisofbonedownthecenter.Theycouldhavebeenusedasfeeblelocomotordevicesonland,perhapsgoodenoughtoallowafishtoflopitswayfromonepoolofwaterthatwasalmostdrytoanadjacentpondthathadenoughwaterandoxygenforsurvival.Thesefinseventuallychangedintoshort,stubbylegs.ThebonesofthefinsofaDevonianrhipidistianexactlymatchinnumberandpositionthelimbbonesoftheearliestknowntetrapods,theamphibians.Itshouldbeemphasizedthattheevolutionoflungsandlimbswasinnosenseananticipationoffuturelifeonland.Theseadaptationsdevelopedbecausetheyhelpedfishtosurviveintheirexistingaquaticenvironment.

Whatecologicalpressuresmighthavecausedfishestograduallyabandontheirwateryhabitatandbecomeincreasinglyland-dwellingcreatures?

ChangesinclimateduringtheDevonianmayhavehadsomethingtodowiththisiffreshwaterareasbecameprogressivelymorerestricted.Anotherimpetusmayhavebeennewsourcesoffood.Theedgesofpondsandstreamssurelyhadscattereddeadfishandotherwater-dwellingcreatures.■Inaddition,plantshademergedintoterrestrialhabitatsinareasnearstreamsandponds,andcrabsandotherarthropodswerealsomembersofthisearliestterrestrialcommunity.■Thus,bytheDevonianthelandhabitatmarginaltofreshwaterwasprobablyarichsourceofproteinthatcouldbeexploitedbyananimalthatcouldeasilyclimboutofwater.■Evidencefromteethsuggeststhattheseearliesttetrapodsdidnotutilizelandplantsasfood;theywerepresumablycarnivorousandhadnotdevelopedtheabilitytofeedonplants.■

Howdidthefirsttetrapodsmakethetransitiontoaterrestrialhabitat?

Likeearlylandplantssuchasrhyniophytes,theymadeonlyapartialtransition;theywerestillquitetiedtowater.However,manyproblemsthatfacedearlylandplantswerenotapplicabletothefirsttetrapods.Theancestorsoftheseanimalsalreadyhadacirculationsystem,andtheyweremobile,sothattheycouldmovetowatertodrink.Furthermore,theyalreadyhadlungs,whichrhipidistianspresumablyusedforauxiliarybreathing.Theprincipalchangesfortheearliesttetrapodswereintheskeletalsystem—changesinthebonesofthefins,thevertebralcolumn,pelvicgirdle,andpectoralgirdle.

P1：

OneofthemostsignificantevolutionaryeventsthatoccurredonEarthwasthetransitionofwater-dwellingfishtoterrestrialtetrapods（four-limbedorganismswithbackbones）.Fishprobablyoriginatedintheoceans,andourfirstrecordsofthemareinmarinerocks.However,bytheDevonianPeriod（408millionto362millionyearsago）,theyhadradiatedintoalmostallavailableaquatichabitats,includingfreshwatersettings.Oneofthegroupswhosefossilsareespeciallycommoninrocksdepositedinfreshwateristhelobe-finnedfish.

1.Paragraph1supportswhichofthefollowingstatementsaboutfishevolution?

A.Lobe-finnedfishwereamongtheearliesttypesoffishtoappear.

B.Fishbeganlivinginfreshwaterhabitatsonlyafteroriginatingelsewhere.

C.Lobe-finnedfishradiatedintoalmostallavailableaquatichabitats.

D.DuringtheDevonian,lobe-finnedfishweremorecommoninmarinethaninfreshwaterhabitats.

P2：

ThefreshwaterDevonianlobe-finnedfishrhipidistiancrossopterygianisofparticularinteresttobiologistsstudyingtetrapodevolution.Thesefishlivedinriverchannelsandlakesonlargedeltas.Thedeltarocksinwhichthesefossilsarefoundarecommonlyredduetooxidizedironminerals,indicatingthatthedeltasformedinaclimatethathadalternatewetanddryperiods.Iftherewereperiodsofdrought,anyadaptationsallowingthefishtosurvivethedryconditionswouldhavebeenadvantageous.Intheserhipidistians，severalsuchadaptationsexisted.Itisknownthattheyhadlungsaswellasgillsforbreathing.Crosssectionscutthroughsomeofthefossilsrevealthatthemudfillingtheinteriorofthecarcassdifferedinconsistencyandtexturedependingonitslocationinsidethefish.Thesedifferencessuggestasadlikecavitybelowthefrontendofthegutthatcanonlybeinterpretedasalung.Gillswereundoubtedlythemainsourceofoxygenforthesefish,butthelungsservedasanauxiliarybreathingdeviceforgulpingairwhenthewaterbecameoxygendepleted,suchasduringextendedperiodsofdrought.So,thesefishhadalreadyevolvedoneoftheprimerequisitesforlivingonland:

theabilitytouseairasasourceofoxygen.

2.Accordingtoparagraph2,whatdothemineralsinthedeltarockscontainingrhipidistiancrossopterygianfossilsreveal?

A.Thesedeltasformedindryperiodsbutgraduallybecamewetter.

B.Thesedeltascontaindifferenttypesofironmineralsthandothesurroundingareas.

C.Mostrhipidistiancrossopterygianfishdiedwhentheclimatebecamedry.

D.Rhipidistiancrossopterygianfishlivedinareasthatexperiencedalternatedryandwetperiods.

3.Theword"advantageous"inthepassageisclosestinmeaningto

A.beneficial

B.necessary

C.remarkable

D.common

4.Inparagraph2,whydoestheauthorincludetheinformationthatmudinsiderhipidistiancrossopterygianfossilsdifferedinconsistencyandtexturedependingonwherethemudwaslocated?

A.Toprovideevidencethatrhipidistiancrossopterygianlivedinriverchannelsandlakesonlargedeltas.

B.Toidentifyaneffectoftheoxidationofironmineralsontheevolutionofrhipidistiancrossopterygian.

C.Tohelpexplainwhyscientistshaveconcludedthatrhipidistiancrossopterygianprobablyhadlungs.

D.Toexplainwhyscientistsdecidedtocutcrosssectionsthroughsomefossilsofrhipidistiancrossopterygian.

5.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage?

Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.

A.Becausethelungsofthesefishwereabletoprovideonlyasmallamountofoxygen,thesefishobtainedmostoftheiroxygenthroughtheirgillsduringperiodsofdrought.

B.Duringperiodsofextendeddrought,thesefishusedtheirlungstoincreasetheirintakeofoxygenbeyondthelevelsabsorbedbythegillsinnormaltimes.

C.Althoughthesefishprimarilyusedtheirgillstoobtainoxygen,theyusedtheirlungstoobtainoxygenfromtheairwhentherewasnotenoughinthewater.

D.Duringperiodsofextendeddrought,thegillsbecameanauxiliarybreathingdeviceandthelungsbecamethemainsourceofoxygenforthesefish.

6.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage?

Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.

A.Becausethelungsofthesefishwereabletoprovideonlyasmallamountofoxygen,thesefishobtainedmostoftheiroxygenthroughtheirgillsduringperiodsofdrought.

B.Duringperiodsofextendeddrought,thesefishusedtheirlungstoincreasetheirintakeofoxygenbeyondthelevelsabsorbedbythegillsinnormaltimes.

C.Althoughthesefishprimarilyusedtheirgillstoobtainoxygen,theyusedtheirlungstoobtainoxygenfromtheairwhentherewasnotenoughinthewater.

D.Duringperiodsofextendeddrought,thegillsbecameanauxiliarybreathingdeviceandthelungsbecamethemainsourceofoxygenforthesefish.

P3：

Asecondadaptationofthesefishwasinthestructureofthelobefins.Thefinswerethick,fleshy,andquitesturdy,withamedianaxisofbonedownthecenter.Theycouldhavebeenusedasfeeblelocomotordevicesonland,perhapsgoodenoughtoallowafishtoflopitswayfromonepoolofwaterthatwasalmostdrytoanadjacentpondthathadenoughwaterandoxygenforsurvival.Thesefinseventuallychangedintoshort,stubbylegs.ThebonesofthefinsofaDevoni