TPO 10 综合写作范文.doc

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1、TPO10Thelectureandreadingpassagebothtalkedabouttwoofthepossiblehypothesesfortheextinctionofseaotters.Whilethearticlewasinfavorofthepollutiontheory,thelecturerdoubteditsvalidityforthefollowingreasons.Tobeginwith,thefirstpieceofevidencethatseaottersdiminishedduetoenvironmentalpollu

2、tionwasitsknownsourcesalongtheAlaskacoast.Ifthatwasthecasethendeadseaottersoughttobefoundalongthecoast.However,asthelecturerepointedout,investigationsdiscoverednoseaottercorpsesalongtheshore.Thisfactcouldperfectlybeexplainedbythepredationtheorybecauseifseaotterswerehuntedbypredat

3、orsandeatenimmediatelyitwouldnotbesuprisingwhennocorpseswerefound.Moreover,thereadingmentionedthatsincethenumberofotherseamammalslikesealionesweredecreasingaswell,thecausecouldnotbepredationastheonlycandidate,orcas,usuallyfeedonlargemammals.Nevertheless,thelecturestatedthatgivent

4、heabsenceoflargerprayitwaslikelyfororcastochangetheirdietfromwhalestosmallseamammalsincludingseaotters.Lastly,regardingtheinconsistentpatternofseaotterdecline,whereinsomeareasthenumberofseaottersremainedconstantwhlieinothersthatwasnotthecase,theauthorofthepassagearguedthatpolluti

5、onhypothesiscouldexplainthisphenomenonwhereasitcouldbebetterexplainedbythepredationhypothesisaccordingtothelecture.Statisticsshowedthatinlocationswithprevalentorcasactivitesseaotterssufferedgreatlossinpopulation.Incontrast,inshallowareaswhereorcascouldnotacesstheseaotterpopulatio

6、ndidnotdecline.