Greenampnbspworld教案

　　greenworld教案
　　thefourthperiod
　　teachingaims：
　　1。getthestudentstograspthemainideaofthetextsoastoimprovetheirreadingability。
　　2。getthestudentstolearnthescientificwayforthescientiststodotheirresearchworkthewaytothinkandobserve。
　　3。getthestudentstowriteadescriptionofplants。
　　teachingimportantpoints：
　　1。howtoanalyseanarticlesoastograspitsmainidea。
　　2。howtowriteadescriptionaccordingtotheinformationgiven。
　　teachingdifficultpoint：
　　howtoimprovethestudents’readingabilityhowtoanalyseanarticle。
　　teachingmethods：
　　1。pairworkorgroupworktomakeeverystudenttakeanactivepartintheclass。
　　2。discussiontogetthestudentstounderstandwhattheyarelearningbetter。
　　teachingaids：
　　1。acomputer
　　2。acourseware
　　3。ataperecorder
　　teachingprocedures：
　　stepgreetingsandrevision
　　greetthewholeclassasusual。
　　t：inthelastperiod，youweretoldtomakesentenceswiththeusefulwordsandexpressionsinthetext。haveyougotprepared？（ss：yes。）nowreadthesentencestous。volunteer！onestudent，onesentence。
　　sa：makeattempttodosth。
　　theymadenoattempttoescape。（atescaping）
　　sb：classify
　　thebooksinourschoollibraryareclassifiedaccordingtosubject。
　　sc：group
　　grouptogetherintwo！
　　sd：identification
　　hecarriesidentificationwithhimatalltimeswhenheisout。
　　se：promote
　　heworkstopromotethefriendshipbetweenthetwocountries。
　　sf：privilege
　　theyfightagainstprivilegeinordertocreateafairersociety。
　　sg：cosy
　　helivesinanicecosylittlehouse。
　　sh：haveanappetitefor
　　theenemyhadnoappetiteforthefight。
　　si：appoint
　　hewasappointedministertoaforeigncountry。
　　sj：calculate
　　thescientistscalculatedwhenthespaceshipwouldreachthemoonwithacalculator。
　　sk：onalargescale
　　theworkofreformingindustrycarriedoutinallprovincesonalargescale。
　　sl：involve
　　thecaseinvolvedseveralleaders。
　　sm：accumulate
　　heaccumulatedafortunebyinvestingwisely。
　　sn：abandon
　　hefoundababyabandonedbyhisparents。
　　steppreparationforreading
　　t：somuchforhomework。nowopenyourbooksandturntopage169。let’sreadthenewwordsandexpressionsofthisperiod。whowillreadthemtous？
　　sa：i’lltry。。。。
　　（teacheraskssomestudentstoreadthenewwordsandexpressions。whilereading，letotherstudentscorrectthemistakesmadebythestudents。thenplaythetapetogetthestudentstofollow。teachermaygivebriefexplanationabouttheirusageswhennecessary。）
　　stepfastreading
　　t：you’velearntsomethingaboutcarllinnaeus，danielsolanderandjosephbanksinthetextwe’vejuststudied。andyou’vereadaboutmichurinanddarwin。today，we’lllearnaboutanothertwoscientistsgregormendelandgoteturesson。whatdidtheydo？whatcontributiondidtheymake？afterwe’velearntthepassage，i’llsureyou’llhaveaclearidea。（showthefollowingonthescreen。）nowreadthetextfastandtrytograspthemainideaofthetextasmuchaspossible。thenfindanswerstothequestionsonthescreen。
　　answerthefollowingquestions：
　　1。whatwascharlesdarwin’shobbywhenhewasyoung？
　　2。whatleddarwintowritehisfamousbookontheoriginofspecies？
　　3。whofoundedthescienceofgenetics？
　　4。whomadecontributiontotheimprovementoftheoutputofcropsaccordingtothetext？
　　（studentsbegintoreadthetext。afterafewminutes，teachersaysthefollowing。）
　　t：haveyoufinished？
　　ss：yes，wehave。
　　t：nowgiveustheanswers，please。onestudent，onequestion。
　　sb：1。whenhewasyoung，darwinenjoyeddoingallkindsofexperimentsandstudyingphysics，chemistryandlaterbotanywashishobby。
　　sc：2。whenhewastwentytwoyearsold，hewasinvitedtotakepartinthescientificexpeditiononthebeagle。hisobservationonthefiveyearvoyageledhimtowritehisfamousbook。ontheoriginofspecies。
　　sd：itwastheresearchworkofmendelthatgavebirthtothescienceofgenetics。
　　se：mendel’sgeneticsandturesson’sfindingsarebothimportanttotheoutputofcrops。
　　t：whatyousaidisright。thankyouforgivingussuchgoodanswers。
　　stepreadingandcomprehension
　　t：（showthefollowingonthescreen。）nowlet’sreadthetextagainanddiscussthequestionsonthescreen。pairworkorgroupwork。
　　1。theresearchofcharlesdarwin，gregormendelandgoteturessonislikepiecesinapuzzlethatshowacompletepicturewhenputtogether。
　　（1）whatdiddarwindiscoveraboutbirdspeciesingalapagos？
　　（2）whatdidmendelobserveinhisexperimentswithpeas？
　　（3）lookingatwildplantspeciesinsweden，whatdidturessondiscover？
　　2。completethefollowingsentence。
　　darwin’sdiscoveriesingalapagoswerebasedondifferenceswildspecies，whileturesson’sobservationsshowedthattherearestablevarietieswildspecies。
　　3。thatsoilconditionsareimportanttotheoutputofcropswasknownmorethanXXyearsago。whyareturesson’sdiscoveriesstillimportanttoagriculturethen？
　　（teachergoesamongthestudentsandjoinsthestudentsintheirdiscussion。）
　　t：（aftersomeminutes’discussion。）nowgiveusyouranswers，please。whowillanswerthefirstquestion？
　　sf：hefound13kindsoffindes，relatedtoeachotherinthestructureoftheirbeaks，tails，shapeofbodyandcolouroftheirfeathers。themostcuriousfactwasthedifferencesinthesizeofthebeaks。thiscouldonlybeexplainedfromthedifferencesinhabitatandsourceoffood。thebirdswithbroadbeakswouldeathardseeds，whilethebirdswithsmallerbeakswouldeatsoftseedsorinsects。
　　t：pleasegiveustheanswerstothesecondquestion。
　　sg：hefoundthatmanycharacteristicswerepassedonfromonegenerationtothenext，withoutinfluencebytheenvironment。
　　sh：i’llanswerthelastquestionofpart1。hefoundevidencefortheexistenceofstablevarietieswithinspeciesinnature。heshowedthatdifferencesbetweenplantsofonespeciesoccurredasaresultoftheenvironmentalconditionsintheirhabitat。
　　si：ithink，inpart2，forthefirstblank，weshouldfillinthewordsofdifferentandthesecond，ofthesame。amiright？
　　t：whatdoyouthink，sj？
　　sj：ithinkheisright。
　　t：forthelastquestion，whatareyouropinions？
　　sk：soilconditionsareimportanttotheoutputofcrops。butthatisonesideofthequestion。theresearchbydarwin，mendalandturessonshowsthatbothgeneticsandtheenvironmentareimportanttoplants。ifwedon’thavegoodseeds，goodsoilconditionsarenotenoughforustoimprovetheoutputofthecrops。amiright？
　　ss：weagreewithyou。
　　（teacherplaysthetapeafterthestudents’discussion。thenteacherasksstudentstoreadthetextaloudandfindquestionsinthetext。teachergivesbriefexplanationtothem。）
　　stepsummaryandhomework
　　t：nowlet’sthinkaboutaquestion：whatcanwelearnfromthetext？（writeitontheblackboard。）discussitwithyourpartner。（afterawhile。）whocantelluswhatyouthink？
　　s1：weshouldobserveeverythingcarefullyandthinkdeeply，thenwecandrawagoodconclusion。
　　。。。
　　t：verygood。nowlet’sseehowthescientistsobserveandthink。
　　（teacherwritesobservation，thinking，conclusion。。。onthebb。）
　　t：somuchforthetext。nowtoday’shomework：
　　1。makesentenceswiththewordsandphrases：
　　leadsb。todosth。；nowhere，inview
　　2。dowritingonpage35。
　　samplewriting：
　　dandelions
　　innature，therearevarietiesofenvironmentalconditionsfortheplantstogrowin。someplacesarehotanddryandthereislittlerainwhileinotherplacesitiscoolandwet。sothesameplantsthatgrowindifferentplacesarequitedifferent。
　　let’stakedandelionsasanexample。theyarewidespreadandcanbefoundalmosteverywhere。theiryellowflowersarebeautifulandtheirleaveslookliketheteethonasaw。thewindspreadtheirflowersandseedseverywhere，sowhentheygrowinhotanddryplaces，theyarelowandthin。theirflowersandleavesareshortandlightincolour，510centimetreslong。theygrowclosetothegroundandtheirrootsaredeepinit。theirheartsarealittlesunkenintotheearth，sothattherainwatercanflowfromtheleavestotheheartwheretherootsare。
　　butinplacesitiscoolandwet，thingsaredifferent。theybecomehigherandstrongerandcangrowaslongas1520centimetres。theirleavesarebroaderandtheirflowersarelarger。thecolouroftheflowersandleavesbecomesdarkergreen。ifsomeweedsaretakenhere，therewillbemanyofthemafewweekslater。
　　agreatswedishscientistgoteturessonsaidthatdifferencesbetweenplantsofonespeciesoccuredasaresultoftheenvironmentalconditionsintheirhabitat。fromdandelionswecanseethisclearly。
　　stepthedesignofthewritingon
　　theblackboard
　　unit4greenworlds
　　thefouthperiod
　　whatcanwelearnfromthetext？
　　steprecordafterteaching