第三次课强化1生物-fiona听力讲义

第一次课生物 第二次课艺 第三次课天 第四次课考古 第五次课环境科 ..........................................................................................................................9 文 四级+场景词汇+456Paragraphs->分层：段落中心改变①①转折③举例④对比⑤强调（⑥否定⑦并列⑧提问Lateralecho-tactilefollicleWhat’sthemainpurposeofthe【主旨】KW：MToexploreapossiblesimilaritybetweenmanateesandToexplorerecentresearchonanimalhairtypesandtheirToshowhowmarinemammalshaveadaptedtovariousoceanTopresentatheoryaboutthevariousfunctionsofanimals’lateralWhatarethreefactorsmentionedbytheprofessorthataffectmanateesabilitytonavigate?[细节]Clickon3TheirlargebodyTheirpoorTheirinabilitytoTherateofwaterflowintheirThelevelofvisibilityintheirHowdotactilehairsdifferfromotherTheyaresoftertotheTheystimulatemorenerveswhentheyTheycansensechangesinTheygrowinstraight-lineWhatdoestheprofessorimplyaboutmanatees’tactile{柯基TheymightservethesamefunctionasalateralTheyprobablyevolvetohelpmanateeshearTheyareusefulonlyduringalimitedperiodofamanatee’sTheyarelocatedonlyonthemanatees’Whatcanbeinferredabouttherecentresearchintomanatees’hairfollicleTheresearchexplainswhymanateescansurviveonlandaswellasunderTheresearchreturnedcontradictoryTheresearchhasledscientiststosearchforhairfolliclesinusesonothermarineTheresearchconfirmedwhatonescientisthadalreadyAccordingtotheprofessor,whatisaquestionthattheresearchersareHowmanatees’navigationalabilitiescomparetothoseofwhalesandHowchangesinwatervisibilitycanaffectmanatees’abilitytoWhethermanateescandetectmotionlessobjectsinWhethermanateescanrememberspecificroutestofoodTPO找一个生物学【步骤第二次课OttavianoPetrucciPierreAttaingnantParisianchansonWhatisthemainpurposeoftheToexplainOttavianoPetrucci’smotivationforprintingTodescribeeffectthatadvancementsinprintinghadonToexamineelementsogscomposedduringtheTocomparethetypesofmusicprintedbyPierreAttaingnantandOttavianoWhydoestheprofessormentionvolumesofTopointoutanadvantageoftheprintingToemphasizetheamountofprintingPetrucciToexplainhowPetrucci’sprintswerepackagedandTomakeapointaboutthecostofPetrucci’sWhatistheprofessor’spointwhenhementionsthatPierreAttangrantattainedanassurancefromthekingofFrance？AttaingnantshouldhaverequestedtheassuranceThekingdidnotsufficientlyconsidertherisksTheassurancemadeitlikelythatAttaingnant’sbusinesswouldPetrucciwouldhavebeenwisetoobtainasimilarWhatdoestheprofessorsayaboutAttaingnant’sClickon2TheycostlessthanPetrucci’sprintsTheywerecompiledintolargeboundTheywereusedmainlybyamateurTheycontainedfewererrorsthanPetrucci’sWhydoestheprofessormentionanToillustrateapotentialchallengeforsingersusingprintedToexplaintheoriginsofParisianToidentifyanadditionalgeneofmusicthatAttaingnantTohelpexplainAttaingnant’smusicalWhatdoestheprofessorsayaboutParisianClickon2ThesongscontainedmorevocalpartsthanothergenresofmusicThesongsrequiredoneperformertoserveastheconductoroftheThesongshadallthesingersstartatthesameThesongsbeginwitheachvocalpartsingingthesame第三次课WhatisthemainpurposeoftheToexplorethepossibilitythatlifemayhaveonceexistedonToshowhowevidenceofwateronTitanwasTodiscussrecentfindingsaboutprecipitationonToexplainhowthemoonsofEarthandSaturnhaveevolvedWhydoestheprofessormentionthediscoveryofalargedarkspotonthesurfaceofTitan?ToidentifyonereasonscientistsnowthinkthatitrainsonTopointoutthedifficultyindistinguishingsurfaceandatmosphericfeaturesonToemphasizethatsurfacewindshavechangedtheToshowhowlakesaredetectedonAccordingtotheprofessor,howdoesTitan’sITCZdifferfromthatofTitan’sITCZdoesnotresultfromtheconvergenceofsurfaceTitan’sITCZremainsatthenorthpolemostoftheThepositionofTitan’sITCZensuresthattropicalprecipitationoccursallyearThepositionofTitan’sITCZshiftsfromonepolarregiontotheAccordingtotheprofessor,whyaretheatmosphericcirculationpatternsonTitansimplerthanthosefoundonEarth?Titan’sITCZkeepsthesepatternsfromTitanrotatemoreslowlythanEarthTitanisamoonratherthanaTitan’shydrologiccycleinvolvesmethaneratherthanWhatdoestheprofessorsayarelikelyresultsoftheverylowtemperaturesonClickon2LakesofliquidmethanecanexistThereisnopossibilityoflifePrecipitationevaporatesquicklyTheITCZmigrateswidelyWhatistheprofessor’sopinionregardingfutureresearchonAstronomersshouldconcentratefornowoninterpretingthedatatheyhavealreadygatheredFutureresear ayprovideadifferentinterpretationofTitan’satmosphericItwillprobablybedifficulttoobtainfundingforadditionalresearissionstoFutureresearchwilladdtoourunderstandingofconditionsonEarthbeforelifeWhatisthemainpurposeoftheToillustratehowphytolithsarebeneficialtoTodemonstratehowphytolithsareusedinscientificTocomparemethodsofysisusedinarchaeologicalToexplainhowmaizewasWhatisonewaythatphytoliths epbetweenminerallayersinGroundwatercausessomeoftheplanttissuetoMineralsfromgroundwatercollectinthecellsofLeavesofplantsphotosynthesizesunlightintoWhatpointdoestheprofessormakeaboutcloselyrelatedplantssuchaswheatandItwasimpossibletoseethedifferencesinthesh oftheirphytolithsuntilTheirseedscanbeidentifiedusingelectronItwasunknownuntilrecentlythattheirphytolithsdecayatdifferentTheirphytolithsaretypicallyfounditinvesselsusedforWhydoestheprofessordiscussTopointoutthatphytolith ysishasprovenhowwidespreaditscultivationactuallywasToprovideanexampleofaplantwhosephytolithsareToemphasizethesurprisingnumberofsubspeciesthatweresuitableforToshowthat ysiscanrevealthetimingofaplant’sWhydoestheprofessordiscussthefunctionofTodescribethereproductiveprocessinsomeToshowwhypollendoesnotdecayasrapidlyasotherpartsofToexplainwhypollencanbeanunreliablesourceforToillustratewhyarchaeologistsfindmorepollenthanphytolithsinWhydoestheprofessorsayToprovideanexplanationforthestatementshejustTofindoutthestudents’opinionsaboutaresearToreviewinformationaboutplanteatersfromlastTosuggestthatplanteatershaveadifficultchoicetoWhatisthelecturemainlyReasonsthatthereintroductionofanativeAustraliangrassspeciesisbeingReasonsthatnonnativecropspecieshavealwaysbeenpreferredinAustralianPlanstointroducemorenonnativegrassspeciesintoTheadvantagesofmixingnativeandnonnativespeciesinAustralianWhydidearlyexpertshaveapooropinionofnativeAustralianTheynoticedthatnativegrassestendedtocrowdoutnonnativeTheyfoundthatnativegrasseshadlittlenutritionalvaluefrazingThenativegrassestheyobservedhadbeendamagedbygrazingThenativegrassestheystudiedhadbeenweakenedbyunusuallydryWhatdoestheprofessorimplyisacharacteristicofnonnativegrassesthatlimitedtheirsuccessinTheyrequireamoreacidicsoilthanmostnativeTheyarepoorlyadaptedtoperiodsofdryTheyareslowtorecoverafterperiodsofTheyarethepreferredfoodofmostgrazingWhatdifferencebetweenweegrassandmorefamiliarplantsdoestheprofessor grassrequireslessspaceto grasstogrowmuoreGrainsof grasstendtobemuchGrainsof grassarehigherinWhatattitudedoestheprofessorhavetowardacerealSheisexcitedbythecommercialsuccessofexportingSheishopefulthatweegrasswillmakeanimportantagriculturalSheisworriedthatfoodsmadefromweegrassmaytastestrangetoSheisconcernedthatthecostofweegrasswillmakeitunprofitableexportWhataretwostrengthsofweeClickon2ItproducesmoreseedsthanmostothergrasslandItgrowsbackquicklyafterbeinggrazedItcangrowinacidicIthasdeepWhatistheconversationmainlyProceduresthestudentshouldusetorequesttimeofherAnevaluationofthestudent’sperformanceatherlibraryAdditionaltasksthestudentwillbeexpectedtocarryThestudent’sinterestinswitchingjobsattheWhatnewjobresponsibilitieswillthestudentClickon2KeetrackofoverdueCheckingbooksinandoutoftheHelstudentsfindReturningbookstotheWhatdoesthestudentimplyabouthercurrentworkatthecirculationShealreadykeepstrackofthe kssheSheoccasionallyhasnothingtoSheistoobusytolearnnewSheappreciatesbeingabletostudyatWhydoesthemanmentionjobToexplainwhyemployeeswillneedtokeepamoredetailedrecordofherToclarifywhythestudentwillbetransformedanotherToaskthestudentwhatpartsofhercurrentjobshelivesToclarifywhythestudent’sdutiesatthecirculationdeskwillWhatisthereasonthatthespeakersdiscussoftheThestudentwillneedmoretimeofffromworktodevotetoherThetrackingofspecificinformationwillberequiredforonlyaThestudentdoesnotplantoworkatthelibrarymuchThetrainingthestudentneedswillnottakeplaceuntilthenextWhatarethespeakersmainlyHowThomtonWilder’searlyexperiencesinfluencedhisHowliterarycriticismcanchangewriter’spartofWhyTheBridgeofSanLuisPayisnolongerapopularWhyThomtonWilderpreformedtowriteinaparticularWhatdoesthemansayaboutthecharactersinTheyarebasedonpeopletheauthormetTheyarebasedontheauthorandhisTheydonotresearchrealTheyallhave WhatdothespeakersimplyaboutthesettingoftheBridgeofSanLuisItenabledWildertoaddresscontemporaryItgaveWilderthefreedomtoconveyhisItlimitedthescopeofWilder’sItencouragedWildertorelyonhisWhatdoesthewomansuggestthemanshoulddoforhispClickon2ExaminethedebatesaboutWilder’sCompareWilder’snovelstohisReadanotheroneofWilder’sChecktheaccuracyofWilder’sdescriptionsofWhydoesthewomansayTofindoutwhetherthemanremembersspecificdetailsfromtheTopointoutthatthesettingofthenovelisignoredbymostToencouragethemantoconsiderthemotivatorsbehindWilder’sapproachtoTosuggestthatthephilosophyexpressedinTheBridgeofSanLuisPayisoftenWhydoesthestudentgotothefacilitiesmanagementToseeifthecomputersneedtobeToconfirmaroomreservationhemadeToseeifhecanaddanadditionalroomtoanexistingTowarntheemployeesaboutnewproblemswiththeirWhichstatementbestdescribestheemployee’sreactiontothestudent’sSheissurprisedthatthevisitedinratherthansendinganSheisgratefulthathehasconfirmedhisroomSheisannoyedthatheisdisturbingherwhilesheSheisrelievedthatheistheretofixthecomputerWhatdoestheemployeesayaretwopossiblecausesofthestudent’sClickon2HisroomrequestformmayhavebeenMultipleroomrequestsunderthesamenamemayhavebeentreatedasSomeoneintheofficemayhaveassignedthesameroomtomorethan.Thecampus-widecomputerproblemshavesignificantlyaffectedtheroomreservationsystem.WhydoesthestudentwanttohavetheeventonFridayItisnotpossibletochangetheroomTheroomheneedsisonlyavailableatthatThespeakerattheeventisleavingonFridayThestudent’sprofessorcannotchangehisWhatdoesthestudentoffertodo oftheSearchtheemployee’scomputerrecordstofinderrorsinroomResubmittheroomrequestthroughanonlinereservationReporttheemployee’scomputerproblemstothetechnologyhelpReturntotheemployee’sofficetohelpherwithhercomputerWhydoestheprofessorwanttoseetheA.Tosuggestthatthestudentreviewhisselectionof Toinformthestudentaboutnewrequirementsforan TosuggestthatthestudentchangethetopicofhispD.ToprovidehelpwithunderstandingsomecomplexscientificpWhydoestheprofessorwarnthestudentaboutaWebsiteheintendedtoA.ItcontradictsfactsfondonauniversityWeb Itsownermaybemotivatedbyfinancial ItexaggeratesthebenefitsofusingtidalD.IthasoutdatedinformationonsolarWhydoesthestudentmentiontidalA.Tomakeacomparisonbetweenthemandsolar Topointouttheenvironmentalbenefitsofusing TodeterminewhetherhisideasabouthowtheyfunctionareD.ToemphasizetheefficiencyoftechnologiesthatuseoceanWhatistheprofessor’sopinionabouttheenvironmentalimpactoftidalA.Theycancausesignificantharmtomarine Theycanprovideenoughenergytooffsetanynegativeeffectonthe Theyhavealmostnoeffectonmarinelife,duetorecenttechnologicalD.Theyhavesomeeffectontheenvironment,butthateffectisstillWhydoestheprofessormentionA.Tosuggestawaythestudentmightharrowthefocusofhisp Toindicatewheretidalturbinesare Topointoutanareathathasfast-movingoceanD.Tonamealocationwheretidalturbineshavehadlittleenvironmental文Iwanttoelaboratealittlebitonsomethingwetalkedaboutlastweekwhenwetalkedabouthowfishnavigate.Wehadbrieflydiscussedthatfishareabletosensechangesinwaterpressureandwatercurrentsbecauseoftheirlateralline.Thelateralline,ifyou’llremember,isalineofsmallholesthatrunshorizontallyalongafish’sbody.Eachoftheseholesisconnectedtoacthatsitsjustunderthefish’sskinandwithinthectherearethesesmallsensoryhairsthatmovebackandforthwhenthey’restimulatedbychangesinwaterpressurefromwaterenteringthec.Thissensitivitytowaterpressureallowsthefishtodetectchangesincurrents,whichhelpsthemtonavigate,tomaketheirwaythroughtheenvironmentandIbringthisupbecauseyouneedtounderstanditfortoday’sdiscussion,whichisactuallyabouthowthemanateenavigates.Youshouldbefamiliarwithmanatees.They’relargemarinemammalsthatarefoundinwarmwater,costalandriverecosystems;placeswheresaltwaterandfreshwatermeet.InNorthAmerica,theycanbefoundinFloridaandtheCaribbean.Themanatee’shabitatisoftencharacterizedbydark,murkywater.Asaresult,it’sverydifficultformanatee’stoseeinthisenvironment.It’sdifficulttoseeanydistance.It’sdifficulttoseeanyobjects.Manateesdon’thaveverygoodvisionanywayandunlikeothermarinemammals,suchaswhalesanddolphins,manateesdon’tuseEcholocation’swhenanimalsproducereallyhigh-frequencyclicksandthendetecttheechoesofthoseclicksthatbounceoffobjectsinthewater.Itallowsanimalslikewhalesanddolphinstosensehowfarawayobjectsareandtonavigate.So,manateescannotecholocateandtheirhabitatmakesvisualorientationlessthanideal.So,howdotheynavigate?Well,manateeshaveanunusualcharacteristic.Theyhavetheseverytoughhairsthatarespacedmoreorlessevenlyallovertheirbodiesandaboutahundredyearsago,onescientist,wellhisinstinctwasanddon’taskmehowhecameupwiththis,wasthatthismighthavesomethingtodowithmanateenavigation.Hisopinionwasthattheseweretactilehairs.Tactilehastodowiththesenseoftouchandtactilehairsaresocalledbecausetheyallowanimalstofeelwhat’sgoingonintheirenvironment.They’redifferentfromotherhairsbecauseofthehairfolliclesinustheysitin.Thehairfolliclesinusisjustlikeasmallsackwithinwhichasinglehairsitsintheskinoftheanimalandimportantly,thesinusisattachedtolotsofnerves;morenervesthanotherkindsofhairfollicles.Sowhenthehairstouchsomethingormove,thenervessensethemovementandsendasignaltothebrain.Now,here’swhatwasalittlepeculiaraboutthescientist’sproposal.Othermammalshavetactilehairs,butthey’reusuallyrestrictedtothefacialregion.Anexampleofthisisthewhiskersoncatsanddogs,sowhatthisscientistwasproposing,justbasedonaninstinct,waskindofunusual,butifhisinstinctwascorrect,thattheseweretactilehairs,thenit’spossiblethesehairsdoconstituteasystemthatenablesnavigation,somethingsimilarinfunctiontowhatfishhave.Anyway,thatwasahundredyearsago,butallofthiscametolightagainrecentlywhenaresearcheryzedsomemagnifiedimagesofmanateehairfollicles.Hefoundoutthatindeedthesearesinusfolliclesandthehairsinthemareindeedtactilehairs,sotogetherthesehairsformasensorysystemformanatees.Whathealsofoundisthatonmanatees,thesehairsarespacedfarenoughapartthattheydon’ttoucheachother,sothattheydon’toverlapandinterferewitheachother.Inotherwords,sothemanateesenseSothisresearchisallveryinteresting,butthebigquestionishowsimilarmanateetactilehairsandfishlaterallinesare.Whatinformationisthemanateereceivingfromthetactilehairs?Like,cantactilehairsallowmanateestodetectstationaryobjectssuchasrockformationsorriverbanks?See,there’spatternsofflowinthewaterandstationaryobjectsdisruptthatflow.Fishperceivethesekindsofdisruptionsbecauseoftheirlaterallinesandtheresearchisongoing,butpreliminaryfindingsseemtosaythatyes,manateeshavethisability.Letstakealooknowatoneparticularexperiment.P:InourdiscussionsofRenaissancemusicuptillnow,we’veestablishedthatwhenmusicwascopiedanddistributedtoothers,itwasallwrittenbyhand.Youcanimaginethetediousnatureofthatwork,right?Todaythough,Iwanttoturnourattentiontoprintedmusic;musicthatwaspublishedthroughtheuseofaprintingpressandwewillseethattheprintingofmusicactuallychangedtheaudienceforitandthereforechangedmusicitself.LetsstartwithamannamedOttavianoPetrucci.MusicprinterOttavianoPetrucciprintedhispublicationsaroundtheyear1500.Theseweregeouspublicationsandtheywereveryexpensivetoproduce,mainlybecausetheyrequiredalotoftimeandagreatdealofprecision.Printedmusicbecame,inshort,aluxuryobjectfortheupperclass.WeknowfromexistingrecordsthatforthepriceofonePetrucciprintofmusic,youcouldpurchaseseveral,yesseveral,volumesofliterature.Therevolutioninmusicprintingcamearound1520withaFrenchprinternamedPierreAttaingnant.ThethingPierreAttaingnantdidwastogetanassurancefromthekingthathewouldbetheonlyonewhocouldsetupamusicprintingshopinallofFrance.Thisisunderstandablesinceitwassuchariskyenterprise,butImean,letsberealistic,withnocompetition,howcouldhehavefailed?Anyway,Attaingnantusedanew,lessexpensivewayofprintingmusicthanPetruccidid.Admittedly,theprintsweren’tasattractiveasPetrucci’sprints,buttheyweremuch,muchcherandtherefore,theyactuallygotused.Theyweren’tjustforcollectorstodisplayonashelfandsincetheygotused,thepritselfdegradedandsowedon’thavenearlyasmanyAttaingnantprintsaswehavePetrucciprints.S1:HowisthemusicAttaingnantprintedP:Well,Attaingnantprintedlotsogsandpeopleweresingingthemfortheirownentertainmentintheirownhomesandthisuse,thisamateursortofdomesticperformancemeantthatthemusicalarrangementsneededtobelesscomplexthanthearrangementsprofessionalmusicianswoulduse.ThisgaverisetoanewgenrecalledParisianchanson.ChansonisaFrenchwordfor‘song.’AlthoughthegenrewaspopularthroughoutEurope,itcametobeknownasParisianchansonbecausesomanyofthesongswereprintedinAttaingnant’sshopinParisandhereisakeyfeatureofParisianchanson.Imagineyou’restandingaroundadinnertablewiththreefriendsgettingreadytosingasongthathasfourdifferentvocalparts.Well,intheprintedmusicbookyouhave,youseeonlyyourlineofmusic,onlythepartthat allybesinginginfrontofyou.S1:Oh,thatmakessense.Thenyouwon’tbedistractedorconfusedbyeveryoneelse’sparts,right?P:True,butactuallyhavingonlyyourpartcouldmakeitabitmorechallengingbecauseyoumightnotknowwhateverybodyelseisabouttosingorevenwho’ssupposedtosing.Like,thinkofanorchestrawithdifferentinstruments.Notallofthestartplayingrightatthebeginningofthesong.Maybejusttheviolinsstartandthenthetrumpetscomeinlaterandsoon,butanorchestrahasaconductortolthemusicianswhentostart,butthere’snoconductorinyourdiningroom,sothecomposersofParisianchansonworkedaroundthisbyhavingallfourvoicepartsstartatthesametimeandinthesamerhythm.Now,asthesongprogressed,therhythms,melodies,andharmoniesdidgetmoredifficult,morevaried,butthesesongsalwayshadeveryonesingingthesamepatternatthebeginning.So,thisisaveryinterestingmomentinmusichistorywhereit’sveryclearthatthebusineseofmusic,thatistosaythesellingofprintedmusicbyPierreAttaingnantandthosewhofollowed,thebusinessendofmusicshdtheartisticend.ThetechnologythatallowedAttaingnanttoproduceinexpensiveprintsaffectedmusicitselfbyleadingtothecreationofanentirelynewgenreofmusic.P:So,we’vetalkedabouttheflatdiskofrockymaterialthatformstherings,orbittheplanet,buttherearealsoover16moonsorbitingSaturn,eachoneuniqueinitsownright.Letsstarttodaybydiscussingonethat’sparticularlyunusual;Titan.Ok,whocanlmewhyTitan’ssounusual?Yes,Lauren?S1:Well,it’sSaturn’slargestmoon.Actuallyit’slargerthantheplanetMercury.P:True,true.Anyoneelse?Robert?S2:It’stheonlyotherworldweknowof,asidefromEarth,thathassomethinglikeahydrologiccycle.P:Ok,goodandwhatdoesthatmeanexactly,hydrologicS2:It’sacyclewhere,wherewaterismovedbetweenliquidandgaseousstatessothere’sevaporation,condensation,andprecipitation.P:Correct.OfcourseonTitan,it’snotwaterthat’sinvolvedinthecycle.It’sactuallymethaneandethane.Iknowwe’reusedtothinkingofmethaneasagas,butonTitanmethanecantaketheformofaliquidandcanbefoundinlakesandpuddles.That’sbecausemethane esaliquidataboutminus108degreesCelsius.OnTitan,that’snothing.Titanissocold,itcanreachtemperaturesaslowasminus183degreesNow,forthepastfewyearswe’vebeenobservingTitananditsatmospherefromaspacecraftcalledCassinithat’sinorbitaroundSaturnandonethingwe’venoticedaboutTitan’ssurfaceisthatitonlyhaslakesatthepoles.Theequatorontheotherhandisunusuallydryandcoveredwithsanddunes,butthere’salsowhatappeartobedried-upchannelsandriverspointingtothepossibilityofrainfallatsomepointinthepast,whiaywellbethecasebecauserecentlywethinkwe’veseenevidenceofrainfallnearTitan’sequator.Ofcourse,wecan’tactuallyseeitrainingfromCassinibecauseitwouldbeobscuredbytheclouds,butwedidseeimagesofalargedarkspotnearTitan’sequatorjustafterthecloudsthatpassedoverthatarea.S1:Oh,Igetit.It’slikewhenitrainsonEarthandthewetsidewalkturnsP:Exactly.Also,thedarkspotstartedfadingveryfast,likewhenevaporating.Now,thisevidenceofrainisprettysignificantbecause,likeIsaid,it’stheexampleofextraterrestrialrainwe’veeverobservedandwhatmaybeevenmoresignificantisthetimingofthisrain.See,there’samodelofTitan’sprecipitationthatpredictsthatequatorialrainwouldonlyoccurduringspringorautumnanditwasspringonTitanwhenCassinitooktheseimages.ThismodelisbasedonsomethingwecalltheInter-TropicalConvergenceZoneorITCZ.Cananyonelmewhatthatis?S1:Yea,isn’ttheITCZtheareaofaplanetwhere,likethesurfacewindsfromthenorthernandsouthernhemispheresmeetorconverge?It’sanareaofprecipitation.P:That’sexactlyright.Now,onEarththiszonestayswithinthetropicsbecausetheweathersystemsonboththenorthandthesouthsidesoftheequatorblocktheITCZinanddon’tallowittomovemuch.That’swhythere’srainfallonourequatoryearround,butonTitan,wethinktheITCZmigratesalmostfrompoletopoleeveryhalfyear,soitbasicallyneverremainsovertheequatorforalongtime.Thatmaybewhywehadn’tseenscienceofequatorialprecipitationuntilnowwhenTitan’sITCZwaspassineritsequatoratthesametimeCassiniwasintheS2:But,Imean,whydoesTitan’sITCZmigratesoP:Well,mostlikelybecauseofTitan’sslowrotationperiod.See,wethinkthatslowrotationscausesimpleratmosphericcirculationpatternsandsimplercirculationpatternsmeanthattherearen’tlargeweathersystemssurroundingtheITCZthatwouldkeepitfromshifting,frommovingfromonepoletotheother.NotlikeonEarthandTitantakesnearly16Earthdaystorotatejustonce.Atanyrate,Titan,withit’squasi-hydrologiccycle,isdefiniyaworldthatweshouldbengresearchon.Yousee,eventhoughit’stoocoldtosustainlife,Titan,withitsmethaneclouds,itsmethaneandethanelakes,Titanmaygiveussomecluesastowhatourplanetwaslikebeforethedevelopmentoflife,soit’simperativethatwestudyTitantobetterunderstandhowEarthmayhavestartedout.Archaeologistshavemanyreasonstobeinterestedinstudyingtheremainsofplants.Historically,humanshavereliedonplantsasasourceofeverythingfrombuildingmaterialtofoodandmedicine.So,identifyingplantremainsatancienthumansiteswouldhelpusgaininsightintothewayoflifeofacultureatagivenpointintime,butplantsdecayquickly,soit’sraretofindintactspecimenstoexamine.Evensuchseeminglysturdystuffasseedsdon’tholdupovertime,sowhatdowedo? y,someplantsleavebehindmicroscopictracesofthemselvesthatdon’tdecay.Pollenandstarchgrains,forexample,havebeenusedinarchaeologicalstudies,ashavewhatarecalledphytoliths.Phytolithsareverytiny,mineraldeposits,almostlikepiecesofhardglass,thatforminthecellsorbetweencellsofmanykindsofplants.Themineralsoriginateinthegroundwaterthattheplantabsorbsthroughitsroots.Whenthewaterrunsthroughtheplant’scells,themineralsaredeposited.So,aphytolithisessentiallyacast;a3-Dimpressionofaplant’scellor,dependingonthespecies,ofthespacebetweencellsandwhentheplantdies,itsphytolithsarereleasedintothesoil.Now,theplantsuffersnoilleffectsfromthephytoliths.Infact,plantscanbenefitfromthem.Forexample,leavesdensewithphytolithsareridgedandbetterabletoabsorbthesunsraysforphotosynthesisandtheseleavescanalsodeterhungryherbivores.Thinkaboutit.Ifyouwereanherbivore,aplanteater,wouldyouprefertochewonanice,softleaforonefullofhardmineraldeposits?Now,researchershavebeenactively yzingphytolithsforaboutfourdecadesandthey’veprovedtobeextremelyimportant.Yousee,inadditiontothefactphytolithsdon’tdecay,theshofaspecies’phytolithsisasuniqueasyourfingerprintsaretoyou,sowecanlwhatspeciesleftbehindthephytolithswehappentobestudyingandwithadvancesintechnology,likecomputerimagingandtheelectronmicroscope,wecanevendistinguishbetweencloselyrelatedplantslikewheatandbarley.Thatincidentallyissomethingwecouldn’tdountilrecentlybecausetheonlytoolwehadwasthestandardlightmicroscope.Theelectronmicroscope,whichuseselectronbeams,allowsustoseedetailswe’dne