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1、TheAmazonrainforestTheAmazonrainforest(inPortuguese,FlorestaAmazônicaorAmazônia;Spanish:SelvaAmazónicaorAmazonia),alsoknownasAmazoniaorAmazonjungle,isamoistbroadleafforestthatcoversmostoftheAmazonBasinofSouthAmerica.Thisbasinencompassessevenmillionsquarekilome
2、ters(1.7billionacres),ofwhichfiveandahalfmillionsquarekilometers(1.4billionacres)arecoveredbytherainforest.Thisregionincludesterritorybelongingtoninenations.ThemajorityoftheforestiscontainedwithinBrazil,with60%oftherainforest,followedbyPeruwith13%,andwithminor
3、amountsinColombia,Venezuela,Ecuador,Bolivia,Guyana,SurinameandFrenchGuiana.StatesordepartmentsinfournationsbearthenameAmazonasafterit.TheAmazonrepresentsoverhalfoftheplanet'sremainingrainforests,anditcomprisesthelargestandmostspecies-richtractoftropicalrainfor
4、estintheworld.TheAmazonrainforestwasshort-listedin2008asacandidatetooneoftheNew7WondersofNaturebytheNewSevenWondersoftheWorldFoundation.AsofFebruary2009theAmazonwasrankingfirstinGroupE,thecategoryforforests,nationalparksandnaturereservesHistoryTherainforestlik
5、elyformedduringtheEoceneera,followingtheevolutionaryappearanceofangiospermplants.ItappearedfollowingaglobalreductionoftropicaltemperatureswhentheAtlanticOceanhadwidenedsufficientlytoprovideawarm,moistclimatetotheAmazonbasin.Therainforesthasbeeninexistenceforat
6、least55millionyears,andmostoftheregionremainedfreeofsavanna-typebiomesduringthattimeperiod.FollowingtheCretaceous–Tertiaryextinctionevent,theextinctionofthedinosaursandthewetterclimatemayhaveallowedthetropicalrainforesttospreadoutacrossthecontinent.From65–34 M
7、ya,therainforestextendedasfarsouthas45°.Climatefluctuationsduringthelast34millionyearshaveallowedsavannaregionstoexpandintothetropics.DuringtheOligocene,forexample,therainforestspannedarelativelynarrowbandthatlaymostlyabovelatitude15°N.Itexpandedagainduringthe
8、MiddleMiocene,thenretractedtoamostlyinlandformationatthelastglacialmaximum.However,therainforeststillmanagedtothriveduringtheseglacialperiods,allowingforthesurvivalandevolutionofab
