高中英语必修三第四单元课件.ppt

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 Whatistheoriginalearth satmospheremadeupof 2 Whydidscientistsbelievewaterisfundamentaltothedevelopmentoflife 3 Howdidwatercomeintobeingontheearth 4 Whichkindoflife beingfirstappearedontheearth plantsoranimals Why 5 Whyweremammalsdifferentfromalllifeformsinthepast Answerthefollowingquestions Carbon nitrogen watervapour andothergases 2 Whydidscientistbelievewaterisfundamentaltothedevelopmentoflife Becausewaterallowedtheearthtodissolveharmfulgasesandacidsintotheoceansandseastoensureafollowingchainreaction whichmadeitpossibleforlifetodevelop Whatistheoriginalearth satmospheremadeupof 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 Whatmanyscientistsbelieveisthatthecontinuedpresenceofwaterallowedtheearthtodissolv