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ID:31282840
大小:105.50 KB
页数:4页
时间:2019-01-08
《巨嘴鸟:森林演变的关键所在》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、巨嘴鸟:森林演变的关键所在 WalkingthroughtheAtlanticcoastalforestsofBrazilinthemorningislikeeavesdropping[偷听]onatoucan[巨嘴鸟]symphony[交响曲].Eachproducesitsownuniquesoundtocutthroughtheauditory[听觉的]clutter[混乱].Butoverthepastcentury,thetoucanshavebeendisappearing.Hunting,far
2、ming,logging[伐木]―it’salltakenabigtoll[产生负面影响]ontoucans. Withfewerandfewerbirds,thetoucansymphonyisdowntoamurmur[低语].They’rejustaboutgonefrommanypartsoftheforest.Anditappearsthattheirdisappearancekickstarted[(比喻)强劲推动]awholeevolutionary[进化的]changeintheforesti
3、tself,particularlyinitspalmtrees. AccordingtoresearchinthejournalScience,thisiswhathappened.Thedominant[占优势的]palmtreedependsonbirdstoeatitsfruitandthendefecate[通便]theseedssomewhere,soitwillgerminate[发芽]andgrowanewtree. MauroGalettiisabiologistattheEstadual
4、PaulistaUniversityinBrazil.Hesaystoucansplayabigpartinthisreproductive[生殖的]process[过程]. MauroGaletti:Theselargebirds,theyhaveanextremely4importantroleintheforestnotonlybecausetheydisperse[散播]seeds,butbecausetheydisperselargeseeds. Thelargestpalmseeds,somet
5、hesizeofmarbles[弹球],aretoobigformostbirdstoeatexceptforthosebig-mouthedtoucans.Soasthetoucansdisappeared,thepalmsthatmadebigseedswereoutofluck―noseeddispersers[分散器].Meanwhile,thepalmsthatwere genetically[从遗传学角度]disposed[处理]tomakesmallseedsdidjustfine;infact
6、,theythrived[茁壮成长]andstartedtodominate[占优势]theforest.Galetti:Theextinction[灭绝]oflargebirdschangedtheevolutionofthispalm. Now,humanshavealwaysbeenmessingwith[干扰]nature.Whenwecutdownforestsorprairie[大草原],orwhenweover-hunt,wechangethemixofplantsandanimals.Buti
7、nthiscase,humansactuallyaltered[改变]thegeneticmakeup[组成]ofawildpalmtreepopulation,injustacentury,byaccident. Sowhathappensifthesesmall-seedpalmseventually[最后]takeover?Well,itturnsoutthatsmallerseedsaren’tsogood.Theydryupanddiefasterinhot,dryweather.Andscient
8、istspredict[预言]thatclimatechangewillmakepartsofBrazilhotteranddrier,somuchsothatthesepalmscouldbeintrouble. Galetti:Theimpacts[冲击]ontheforestcanbequite4dramatic[戏剧性的]becauseseveralanimalspecies
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