高中英语必修三第四单元ppt课件

.,Unit4,Astronomy:thescienceofthestars,Howmuchdoyouknowabouttheuniverse?,Whatarethenamesoftheeightplanetsthatcircleoursun?Whatistheirorderfromthesun?,地球_木星_火星_水星_,海王星_土星_天王星_金星_,Earth,Jupiter,Mars,Mercury,Neptune,Saturn,Uranus,Venus,1.Howoldistheuniverse?2.Howoldistheearth?3.Whichwerethefirstcreatureorplantsonearth?4.Doyouknowwhattheorderforthedevelopmentofplantsandanimalsis?,Severalbillionyearsago.,Between4.5and3.8billionyearsago.,Verysmallair-breathingcreatures.,FreeTalk,.,Ideasabouthowlifebegan,.,reading,HowLifeBeganontheEarth,Fastreading,Readthepassagequicklyandfindthemainidea.,Abriefintroductiononhowtheuniversedevelopedandhowlifebeganontheearth.,Carefulreading,Para1:,Para2:Para3:Para4:,Para5:,Awidelyacceptedtheoryabouttheformationoftheuniverse.,Theformationoftheearth.,Theimportanceofwaterforlife.,Thedevelopmentofplantsandanimalsontheearth.,Thearrivalofhumansandtheirimpactontheearth.,Readthepassagecarefullyandanalyseitsstructure.,earth,atmosphereandwater,lifedevelopment,humanbeings,1.Whatistheoriginalearthsatmospheremadeupof?2.Whydidscientistsbelievewaterisfundamentaltothedevelopmentoflife?3.Howdidwatercomeintobeingontheearth?4.Whichkindoflife-beingfirstappearedontheearth,plantsoranimals?Why?5.Whyweremammalsdifferentfromalllifeformsinthepast?,Answerthefollowingquestions.,Carbon,nitrogen,watervapour,andothergases.,2.Whydidscientistbelievewaterisfundamentaltothedevelopmentoflife?,Becausewaterallowedtheearthtodissolveharmfulgasesandacidsintotheoceansandseastoensureafollowingchainreaction,whichmadeitpossibleforlifetodevelop.,Whatistheoriginalearthsatmospheremadeupof?,3.Howdidwatercomeintobeingontheearth?,Theexplosionoftheearthproducedwatervapor,whichturnedintowaterwhentheearthcooleddown.,4.Whichkindoflife-beingfirstappearedontheearth,plantsoranimals?Why?,Atfirst,smallplantsbegantoappearonthesurfaceofthewater,theyproduceoxygen,whichencouragedthelaterdevelopmentofearlyshellfishandallsortsoffish.,5.Whyweremammalsdifferentfromalllifeformsinthepast?,Theyweredifferentbecausetheyproducedtheiryoungfromwithintheirbodiesandproducemilktofeedthem.,（）1Insectsandamphibiansappeared.（）2Dinosaursappeared.（）3Theearthbecameasolidball.（）4Smallplantsgrewonthewater.（）5Reptilesappeared.（）6Plantsbegantogrowondryland.（）7Theearthwasacloudofdust.（）8Waterappearedontheearth.（9Shellfishandotherfishappeared.（）10Theuniversebeganwitha“BigBang”.（）11Cleveranimalswithhandsandfeetappeared.（）12Mammalsappeared.,8,7,5）,6,4,1,10,3,9,2,Puttheorderofdevelopmentoflife.,12,11,Letreviewtheevolutionoflifeontheearth.,Afterthe“BigBang”,theearthwasfullofwater.,Originalcellsappearedintheocean.,Thecellsinthewaterbegantoseparate.Smallplantscameintobeing.,.,Earlyshellfishandallsortsoffish,Someanimals(amphibian&insects)cametoland.,Reptileappeared.,dinosaurs,mammals,Manhadevolvedfromapes.,.,Wearemakingtheworldbetter.,Wearemakingtheworldworse.,Discussion,.,Becausetheyareputtingtoomuchcarbondioxideintotheatmosphere.,Theearthmaybecometoohottoliveon.,.,Theearthisbecominghotterandhotter!,solarenergy,planttrees,recyclerubbish,preventdesertification,savewater,purifyair,Whatcanwedototakecareoftheearth?,.,Whetherlifewillcontinueontheearthdependsonhumanbeings.,.,精讲点拨,Theearthbecamesoviolentthatitwasnotclearwhethertheshapewouldlastornot.Whatmanyscientistsbelieveisthatthecontinuedpresenceofwaterallowedtheearthtodisso