高中英语外研版2019选择性必修第二册课件：Unit 5 A delicate world (2)-Using language

选择性必修二Unit5Adelicateworld(2)

高二年级英语UsinglanguageEcosystems

ListeningandspeakingObjectives

Attheendoftheclass,youwillbeableto:1.acquirewordsandexpressionsrelatedtoecosystems2.obtaintherelationshipsbetweenthelivingthings3.getthespecificinformationandchoosethetruestatements4.takedownsomeinformationandexpressionsexpressingdoubtandrespondingtodoubt

5.actoutaconversationabouttheecosystem,usingthewordsandexpressionsyouhavelearntObjectives

WarmingupLookatthediagramonPage54andanswerthequestions.Q1:Whatdoesthediagramshow?Q2:Whataretherelationshipsbetweenthelivingthings?Checkingtheanswers1.Whatdoesthediagramshow?The

diagramshowsafoodchain—

theconnectionbetweenthelivingthings.Checkingtheanswers2.Whataretherelationshipsbetweenthelivingthings?Thelivingthingsarecloselyconnectedwitheachotherbythefood

they

eat.Secondaryconsumerspreyonprimaryconsumers.Primaryconsumersfeedonproducers.Producersabsorblightfromthesun,wateranddissolovednutrientsfromthesoil,whichareprovidedbydecomposers.Inthewoodlandecosystem,treesandotherplantsareproducers.Theywaterandtakeinnutrientsfromthesoilandenergyfromthesun.CompletethepassagewiththecorrectformofthewordsandexpressionsinActivity5.absorbInsectsareanexampleofaprimaryconsumer.Theytheproducerstoprovidefoodforthem,andarebysecondaryconsumers:smallmammalsandbirds.relyonfedonTheytheprimaryconsumers.Worms,fungiandbacteriaaredecomposers.Theyanimalwasteandtheremainsoflivingthings.Thechemicalsthesedecomposersfertilisethesoilandgivetheplantsthenutrientstheyneedtogrow.preyonbreakdownreleaseReadaboutbeesonPage55.

Whatdoyouknowaboutbees?1.Theyhavebeeninexistenceformillionsofyears.2.Theycanfly24kilometresperhour.Thewingscanbeat200timespersecond.3.Onebeecanpollinate50—100flowers.Listeningformainidea

Whatwillbetalkedabout?ListentotheconversationinActicity7onPage55,andchoosethetruestatements.1.Beesareveryimportanttoourfoodsupplybecausetheyprovidehoney.2.Thebeepopulationisdeclining.3.Withoutbees,humanswoulddieout.4.Allhumancropsdependonbeesforpollination.5.Ifbeesbecameextinct,otherinsectscouldpollinateenoughcrops.6.Humansareresponsibleforthedeclineinthebeepopulation.Checkingtheanswers1.Beesareveryimportanttoourfoodsupplybecausetheyprovidehoney.2.Thebeepopulationisdeclining.3.Withoutbees,humanswoulddieout.4.Allhumancropsdependonbeesforpollination.5.Ifbeesbecameextinct,otherinsectscouldpollinateenoughcrops.6.Humansareresponsibleforthedeclineinthebeepopulation.ListeningfordetailedinformationTask1:Listenagainandcompletetheflowchart.CheckingtheanswersAcombinationofthingsdamagesbeehabitats,mainly1.Thebeepopulationis2.Accordingtostatistics,beenumbersintheUS3injustoneyear.pesticidesandclimatechangedecliningveryquicklyhavefallenby70%CheckingtheanswersWithoutbees,cropswould4.5wouldnotbeabletocompensateforthelossofbees,because6ofthespeciesofcrops.Animalsthatliveonthecrops7.

beunabletoreproduceOtherinsectsbeesareresponsibleforpollinatingabout70%woulddieoutListeningfordetailedinformationTask2.Discussandtalkabouttheimportanceofbees.

SampleBeesareveryimportant.Withoutbees,cropswouldbeunabletoreproduce.Meanwhile,otherinsectswouldnotbeabletocompensateforthelossofbees,becausebeesareresponsibleforpollinatingabout70%ofthespeciesofcrops.

SampleWithoutbees,numerousplantsspecieswoulddieout.Asaresult,animalsthatliveonthecropswoulddisappear,andhumanswouldhavenothingtoeat.ListeningforspeakingCompletetheboxinActivity9withtheusefulexpressionsfromtheconversation.CheckingtheanswersExpressingdoubtYoumustbekidding!Idon’tbelieveit!Areyousureabout...?CheckingtheanswersRespondingtodoubtIt’safact!Don’tforgetthat...Checkitoutforyourself...Accordingtostatistics...SpeakingActoutaconversationaboutwhatwouldhappentotheecosystemifanotherspeciesdiedout.Usethewordsandexpressionsinthissection.

Criteriaforspeakingcontentlanuage(usefulexpressions)Pronunciation&intonationSpeakingStudentA:Hey,Mark,whatdoyouthinkwouldhappentotheecosystemifwolvesdiedout?StudentB:Idon’tthinkithasabigimpactontheecosystem.StudentA:Ifwolvesdiedout,itwouldthreatentheplanet’sbalance.StudentB:What?!Youmustbekidding!Idon’tbelieveit!SpeakingStudentA:It’safact!Iwatchedanaturearticleaboutit.StudentB:Howcanthatbepossible?StudentA:Wolvesfeedonsheep.Peoplecaptureandkillthemtogetmorebenefitsfromsheep,whichcausesthewolfpopulationdecliningquickly.Withoutwolves,sheepwouldstartbreeding,andthenumberofsheepwouldbelargerandlarger.StudentB:Somoremilk,meat,andfurwouldbeprovidedtopeople.SpeakingStudentA:Itsoundsreasonable.Don’tforgetthatthewildrabbitsandcowscompeteforthegrasswithsheep.Yearslater,thenumberofgrasswouldbegreatlyreduced.Inturn,numeroussheepwoulddieofstarvation.Evenworse,muchofthegrasslandwouldbecomedesert.StudentB:That’sscary.SpeakingStudentA:Rememberthatweareapartofthefoodchain,sowewouldbeindangertoo!StudentB:Obviously,humanactivityisthemaincause.StudentA:That’