Unit5Usinglanguagelistening&vocabularyWhatdoyouknowaboutbiodiversity?bio+diversitymeans“l(fā)ife”means“variety”speciesgeneecosystemcell細(xì)胞,bacteria細(xì)菌,germs病毒有機的免疫系統(tǒng)P71madeupofcellsbricksthatareusedtobuildhousesthirtytrillionthirty-ninetrillionhelpwithdigestionbreakdownJenny:Hello,andwelcometoScienceUndertheMicroscope,ascienceprogrammeforteens.I'mJenny.Josh:AndI'mJosh.Jenny:Thisweek,aspartofourseriesonbiodiversity,wearediscussingmicroorganisms.TheyaretheoldestformoflifeonEarth.Scientistsbelievetheyfirstemergedaroundthreeandahalfbillionyearsago!Josh:That'sincredible!Jenny:Butyoucanonlyseethemwithamicroscope,astheselivingthingsareveryverysmall.We'retalkingaboutlifeatthelevelofthecell.Doyouknowaboutcells,Josh?Josh:Erm...I'mafraidnot.Whatexactlyisacell?Jenny:Everylivingthingismadeupofcells.Theyarelikebricksthatareusedtobuildhouses.Bytheway,mostmicroorganismsaresingle-celled.Thismeansthattheyconsistofjustonecell.Josh:Howstrange!Jenny:Actually,we'retheoneswhoareunusual.Thevastmajorityoflifeonthisplanetismadeupofsingle-celledmicroorganisms.They'reeverywhere!Intheair,inwater,thereareevenmicroorganisms...insideyou.I'mtalkingaboutbacteria.Haveyouheardofbacteria,Josh?Josh:Ihave,Jenny.Butbacteria,insideme?Yuck!Jenny:[laughs]That'sright.Youhavelotsofthemlivinginyourbody.Infact,anaveragehumanbodycontainsaboutthirtytrillionhumancells,andaroundthirty-ninetrillionbacteriacells.Josh:Seriously?Oh,thisismakingmystomachturn.Jenny:Speakingofwhich,mostofthebacteriainyourbodyhelpwithdigestion.Andtheyhelpmakethefoodthatgoesintoyourstomach,too.Withoutbacteria,wewouldn'tbeabletomakecheese,yoghurt,vinegar...Josh:Really?Ididn'tknowthat!Jenny:Oh,andbacteriaarealsousefulattheotherendofthefoodproductionprocess.Theyhaveanimportantroledealingwithyourwasteandthatofotherorganisms.Josh:Euw!Youmeanwhatgoesdownthetoilet?Jenny:Yes.Bacteriabreakdownthiswasterandotherdead,organicmatter,likefallenleaves,intonutrients.Josh:Oh,Igetit.Andthesenutrientsgobackintothesoilwheretheycanbeusedbyplants!Jenny:That'sitexactly.Josh:Allright.Althoughsomeofthebacteriamaycausediseasesinhumans,plantsandanimals,theyaren'tallbad...Doyouknowabout…?Haveyouheardof…?Bytheway…Actually…Infact,…Speakingofwhich,…What

species

are

mentionedandwhatisspecialaboutthem?Species種類Features特征bacteria&virusesextremelysmallsizeblueWhalethelargestsizewaterbearextremetoughness

unknownspeciesvastnumberawaitingdiscoveredWhat

otherunusuallifeformsdoyouknowof?Whatarethey?gianttortoisemangrovesiguanacoastalplantscomb-likespinestheGalapagosislandsMatchthewordswiththeirdefinitionsancestorscientificbenativetoprimitivehabitatappearancebehometoecosystemEFDBAGHC源于…的原始的，低等的棲息地是…的家園生態(tài)系統(tǒng)ishometoarenativetoscientifichabitatsecosystemappearanceprimitiveancestorTalkaboutbiodiversityinChinausingthewordswe’velearnt.ThedesertecosysteminNorthwestChinaishometothehardydiversiform-leavedpoplar,whichhelpsprotectthehabitatfromsandstorms.胡楊水杉東北虎牦牛Scientificres