阅读理解。ArecentstudyofancientandmodernelephantshascomeupwiththeunexpectedconclusionthattheAfricanelephantisdividedintotwodistinct(不同的)species.ThediscoverywasmadebyresearchersatYorkandHarvardUniversitieswhentheywereexaminingthegeneticrelationshipbetweentheancientwoollymammothandmastodontomodernelephants—theAsianelephant,Africanforestelephant,andAfricansavannaelephant.OncetheyobtainedDNAsequences(序列)fromtwofossils(化石),mammothsandmastodons,theteamcomparedthemwithDNAfrommodernelephants.TheyfoundtotheiramazementthatmodernforestandsavannaelephantsareasdistinctfromeachotherasAsianelephantsandmammoths.ThescientistsuseddetailedgeneticanalysistoprovethattheAfricansavannaelephantandtheAfricanforestelephanthavebeendistinctspeciesforseveralmillionyears.ThedivergenceofthetwospeciestookplacearoundthetimeofthedivergenceofAsianelephantsandwoollymammoths.Thisresultamazedallthescientists.Therehaslongbeendebateinthescientificcommunitythatthetwomightbeseparatespecies,butthisisthemostconvincingscientificevidencesofarthattheyareindeeddifferentspecies.Previously,manynaturalistsbelievedthatAfricansavannaelephantsandAfricanforestelephantsweretwopopulationsofthesamespecies,despitetheelephants'significantsizedifferences.Thesavannaelephanthasanaverageshoulderheightof3.5metreswhiletheforestelephanthasanaverageshoulderheightof2.5metres.Thesavannaelephantweighsbetweensixandseventons,roughlydoubletheweightoftheforestelephant.Butthefactthattheylooksodifferentdoesnotnecessarilymeantheyaredifferentspecies.HowevertheprooflayintheanalysisoftheDNA.AlfredRoca,assistantprofessorintheDepartmentofAnimalSciencesattheUniversityofIllinois,said,“Wenowhavetotreattheforestandsavannaelephantsastwodifferentunitsforconservationpurposes.Since1950,allAfricanelephantshavebeenconservedasonespecies.Nowthatweknowtheforestandsavannaelephantsaretwoverydistinctiveanimals,theforestelephantshouldbecomeabiggerpriority(优先)forconservationpurposes.”本文讲述了一项新的科学发现：通过对非洲森林大象和非洲草原大象DNA的鉴定，科学家们得出结论：它们是两种不同的物种。我们要保护这些珍稀动物。1．Oneoft