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投顶网___.touding.com像玩游戏一样开心学习、开心背单词,一起PK吧投顶网___.touding.comhttp://___.touding.com/\t_blank
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3.免费、不用下载、不用__您也可以加入投顶网的__群58435079或者69620265一起讨论投顶网最近推出了每天登陆开心背单词送宝物还推出了自己闯关的玩法!!感觉内容好,请转发给身边的同学和朋友!01TheLanguageofMusicApainterhangshisorherfinishedpicturesonawallandeveryonecanseeit.Acomposerwritesaworkbutnoonecanhearituntilitisperformed.Professionalsingersandplayersh__egreatresponsibilitiesforthecomposerisutterlydependentonthem.Astudentofmusicneedsaslongandasarduousatrainingtobecomeaperformerasamedicalstudentneedstobecomeadoctor.Mosttrainingiscon__rnedwithtechniqueformusiciansh__etoh__ethemuscularproficiencyofanathleteoraballetdan__r.Singerspracti__breathingeverydayastheirvocalchordswouldbeinadequatewithoutcontrolledmuscularsupport.Stringplayerspracti__movingthefingersofthelefthandupanddownwhiledrawingthebowtoandfrowiththerightarm-twoentirelydifferentmovements.Singersandinstrumentsh__etobeabletogeteverynoteperfectlyintune.Pianistsaresparedthisparticularanxietyforthenotesarealreadytherewaitingforthemanditisthepianotuner’sresponsibilitytotunetheinstrumentforthem.Buttheyh__etheirowndifficulties;thehammersthathitthestringh__etobecoaxednottosoundlikepercussionandeachoverlappingtonehastosoundclear.Thisproblemofgettingcleartextureisonethatconfrontsstudentconductors:theyh__etolearntoknoweverynoteofthemusicandhowitshouldsoundandtheyh__etoaimatcontrollingthesesoundswithfanaticalbutselflessauthority.Techniqueisofnouseunlessitiscombinedwithmusicalknowledgeandunderstanding.Greatartistsarethosewhoaresothoroughlyathomeinthelanguageofmusicthattheycanenjoyperformingworkswritteninany__ntury.02SchoolingandEducationItiscommonlybelievedinUnitedStatesthatschooliswherepeoplegotogetaneducation.Neverthelessithasbeensaidthattodaychildreninterrupttheireducationtogotoschool.Thedistinctionbetweenschoolingandeducationimpliedbythisre__rkisimportant.Educationismuchmoreopen-endedandall-inclusivethanschooling.Educationknowsnobounds.Itcantakepla__anywherewhetherintheshowerorinthejobwhetherinakitchenoronatractor.Itincludesboththefor__llearningthattakespla__inschoolsandthewholeuniverseofinfor__llearning.Theagentsofeducationcanrangefromareveredgrandparenttothepeopledebatingpoliticsontheradiofromachildtoadistinguishedscientist.Whereasschoolinghasa__rtainpredictabilityeducationquiteoftenprodu__ssurprises.Achan__conversationwithastranger__yleadapersontodiscoverhowlittleisknownofotherreligions.Peopleareengagedineducationfrominfancyon.Educationthenisaverybroadinclusiveterm.Itisalifelongpro__ssapro__ssthatstartslongbeforethestartofschoolandonethatshouldbeanintegralpartofone’sentirelife.Schoolingontheotherhandisaspecificfor__lizedpro__sswhosegeneralpatternvarieslittlefromonesettingtothenext.Throughoutacountrychildrenarriveatschoolatapproxi__telythesametimetakeassignedseatsaretaughtbyan_____usesimilartextbooksdohomeworktakeexamsandsoon.Thesli__sofrealitythataretobelearnedwhethertheyarethealphabetoranunderstandingoftheworkingofgover__enth__eusuallybeenlimitedbytheboundariesofthesu__ectbeingtaught.Forexamplehighschoolstudentsknowthattherenotlikelytofindoutintheirclassesthetruthaboutpoliticalproblemsintheircommunitiesorwhatthenewestfilm__kersareexperimentingwith.Therearedefiniteconditionssurroundingthefor__lizedpro__ssofschooling.03TheDefinitionof“Pri__”Pri__sdeterminehowresour__saretobeused.Theyarealsothemeansbywhichproductsandservi__sthatareinlimitedsupplyarerationedamongbuyers.Thepri__systemoftheUnitedStatesisacomplexnetworkcomposedofthepri__sofalltheproductsboughtandsoldintheeconomyaswellasthoseofamyriadofservi__sincludinglaborprofessionaltransportationandpublic-utilityservi__s.Theinterrelationshipsofallthesepri__s__keupthe“system”ofpri__s.Thepri__ofanyparticularproductorservi__islinkedtoabroadcomplicatedsystemofpri__sinwhicheverythingseemstodependmoreorlessuponeverythingelse.Ifoneweretoaskagroupofrandomlyselectedindividualstodefine“pri__”__nywouldreplythatpri__isanamountofmoneypaidbythebuyertothesellerofaproductorservi__orinotherwordsthatpri__isthemoneyvaluesofaproductorservi__asagreeduponina__rkettransaction.Thisdefinitionisofcoursevalidasfarasitgoes.Foracompleteunderstandingofapri__inanyparticulartransactionmuchmorethantheamountofmoneyinvolvedmustbeknown.Boththebuyerandthesellershouldbefamiliarwithnotonlythemoneyamountbutwiththeamountandqualityoftheproductorservi__tobeexchangedthetimeandpla__atwhichtheexchangewilltakepla__andpaymentwillbe__detheformofmoneytobeusedthecredittermsanddiscountsthatapplytothetransactionguaranteesontheproductorservi__deliverytermsreturnprivilegesandotherfactors.Inotherwordsbothbuyerandsellershouldbefullyawareofallthefactorsthatcomprisethetotal“package”beingexchangedfortheasked-foramountofmoneyinorderthatthey__yevaluateagivenpri__.04ElectricityThemodernageisanageofelectricity.Peoplearesousedtoelectriclightsradiotelevisionsandtelephonesthatitishardtoi__ginewhatlifewouldbelikewithoutthem.Whenthereisapowerfailurepeoplegropeaboutinflickeringcandlelightcarshesitateinthestreetsbecausetherearenotrafficlightstoguidethemandfoodspoilsinsilentrefrigerators.Yetpeoplebegantounderstandhowelectricityworksonlyalittlemorethantwo__nturiesago.Naturehasapparentlybeenexperimentinginthisfieldformillionofyears.Scientistsarediscoveringmoreandmorethatthelivingworld__yhold__nyinterestingsecretsofelectricitythatcouldbenefithu__nity.Allliving__llsendouttinypulsesofelectricity.Astheheartbeatsitsendsoutpulsesofrecord;theyformanelectrocardiogramwhichadoctorcanstudytodeterminehowwelltheheartisworking.Thebraintoosendsoutbrainw__esofelectricitywhichcanberecordedinanelectroen__phalogram.Theelectriccurrentsgeneratedbymostliving__llsareextremely__all-oftenso__allthatsensitiveinstrumentsareneededtorecordthem.Butinsomeani__ls__rtainmuscle__llsh__ebecomesospecializedaselectricalgeneratorsthattheydonotworkasmuscle__llsatall.Whenlargenumbersofthese__llarelinkedtogethertheeffectscanbeastonishing.Theelectriceelisana__zingstoragebattery.Itcanseedajoltofasmuchaseighthundredvoltsofelectricitythroughthewaterinwhichitlive.Anelectrichousecurrentisonlyonehundredtwentyvolts.As__nyasfour-fifthsofallthe__llsintheelectriceel’sbodyarespecializedforgeneratingelectricityandthestrengthoftheshockitcandelivercorrespondsroughlytolengthofitsbody.05TheBeginningofDra__Thereare__nytheoriesaboutthebeginningofdra__inancientGreece.Theonmostwidelyac__ptedtodayisbasedontheassumptionthatdra__evolvedfromritual.Theargumentforthisviewgoesasfollows.Inthebeginninghu__nbeingsviewedthenaturalfor__softheworld-eventheseasonalchanges-asunpredictableandtheysoughtthroughvariousmeanstocontroltheseunknownandfearedpowers.Thosemeasureswhichappearedtobringthedesiredresultswerethenretainedandrepeateduntiltheyhardenedintofixedrituals.Eventuallystoriesarosewhichexplainedorveiledthemysteriesoftherites.Astimepassedsomeritualswereabandonedbutthestorieslatercalledmythspersistedandprovided__terialforartanddra__.Thosewhobelievethatdra__evolvedoutofritualalsoarguethatthoseritescontainedtheseedoftheaterbecausemusicdan____sksandcostumeswerealmostalwaysusedfurthermoreasuitablesitehadtobeprovidedforperfor__n__sandwhentheentirecommunitydidnotparticipateacleardivisionwasusually__debetweentheactingareaandtheauditorium.Inadditiontherewereperformersandsin__considerableimportan__wasattachedto__oidingmistakesintheenactmentofritesreligiousleadersusuallyassumedthattask.Wearing__sksandcostumestheyoftenimpersonatedotherpeopleani__lsorsupernaturalbeingsandmimedthedesiredeffect-suc__ssinhuntorbattlethecomingraintherevivaloftheSun-asanactormight.Eventuallysuchdra__ticrepresentationswereseparatedfromreligiousactivities.Anothertheorytra__sthetheater’soriginfromthehu__ninterestinstory____ing.Accordingtothisviestalesaboutthehuntwarorotherfeatsaregraduallyelaboratedatfirstthroughtheuseofimpersonationactionanddialoguebyanarratorandthenthroughtheassumptionofeachoftherolesbyadifferentperson.Acloselyrelatedtheorytra__stheatertothosedan__sthatarepri__rilyrhythmicalandgymnasticorthatareimitationsofani__lmovementsandsounds.06TelevisionsTelevision-----themostpervasiveandpersuasiveofmoderntechnologies__rkedbyrapidchangeandgrowth-ismovingintoaneweraaneraofextraordinarysophisticationandversatilitywhichpromisestoreshapeourlivesandourworld.Itisanelectronicrevolutionofsorts__depossiblebythe__rriageoftelevisionandcomputertechnologies.ThewordtelevisionderivedfromitsGreektele:distantandLatinvisio:sightrootscanliterallybeinterpretedassightfromadistan__.Verysimplyputitworksinthisway:throughasophisticatedsystemofelectronicstelevisionprovidesthecapabilityofconvertingani__gefocusedonaspecialphotoconductiveplatewithinacameraintoelectronicimpulseswhichcanbesentthroughawireorcable.Theseimpulseswhenfedintoare__ivertelevisionsetcanthenbeelectronicallyreconstitutedintothatsamei__ge.Televisionismorethanjustanelectronicsystemhowever.Itisameansofexpressionaswellasavehicleforcommunicationandassuchbecomesapowerfultoolforreachingotherhu__nbeings.Thefieldoftelevisioncanbedividedintotwocategoriesdeterminedbyitsmeansoftran__ission.Firstthereisbroadcasttelevisionwhichreachesthe__ssesthroughbroad-basedairw__etran__issionoftelevisionsignals.Secondthereisnonbroadcasttelevisionwhichprovidesfortheneedsofindividualsorspecificinterestgroupsthroughcontrolledtran__issiontechniques.Traditionallytelevisionhasbeenamediumofthe__sses.Wearemostfamiliarwithbroadcasttelevisionbecauseithasbeenwithusforaboutthirty-sevenyearsinaformsimilartowhatexiststoday.DuringthoseyearsithasbeencontrolledforthemostpartbythebroadcastnetworksABCNBCandCBSwhoh__ebeenthe__jorpurveyorsofnewsinfor__tionandentertai__ent.Thesegiantsofbroadcastingh__eactuallyshapednotonlytelevisionbutourper__ptionofitaswell.Weh__ecometolookuponthepicturetubeasasour__ofentertai__entplacingourroleinthisdynamicmediumasthepassiveviewer.07AndrewCarnegieAndrewCarnegieknownastheKingofSteelbuiltthesteelindustryintheUnitedStatesandinthepro__ssbecameoneofthewealthiestmeninAmerica.Hissuc__ssresultedinpartfromhisabilitytoselltheproductandinpartfromhispolicyofexpandingduringperiodsofeconomicdeclinewhenmostofhiscompe_____swerereducingtheirinvestments.Carnegiebelievedthatindividualsshouldprogressthroughhardworkbuthealsofeltstronglythatthewealthyshouldusetheirfortunesforthebenefitofsociety.Heopposedcharitypreferringinsteadtoprovideeducationalopportunitiesthatwouldallowotherstohelpthemselves.Hewho___srich___sdisgra__dheoftensaid.AmonghismorenoteworthycontributionstosocietyarethosethatbearhisnameincludingtheCarnegieInstituteofPitt__urghwhichhasalibraryamuseumoffineartsandamuseumofnationalhistory.HealsofoundedaschooloftechnologythatisnowpartofCarnegie-MellonUniversity.OtherphilanthropicgiftsaretheCarnegieEndowmentforInternationalPea__topromoteunderstandingbetweennationstheCarnegieInstituteofWashingtontofundscientificresearchandCarnegieHalltoprovidea__nterforthearts.FewAmericansh__ebeenleftuntouchedbyAndrewCarnegie’sgenerosity.Hiscontributionsofmorethanfivemilliondollarsestablished2500librariesin__allcommunitiesthroughoutthecountryandformedthenucleusofthepubliclibrarysystemthatweallenjoytoday.08AmericanRevolutionTheAmericanRevolutionwasnotasuddenandviolentoverturningofthepoliticalandsocialframeworksuchaslateroccurredinFranceandRussiawhenbothwerealreadyindependentnations.Significantchangeswereusheredinbuttheywerenotbreathtaking.Whathappenedwasac__leratedevolutionratherthanoutrightrevolution.Duringtheconflictitselfpeoplewentonworkingandpraying__rryingandplaying.Mostofthemwerenotseriouslydisturbedbytheactualfightingand__nyofthemoreisolatedcommunitiesscar__lyknewthatawarwason.America’sWarofIndependen__heraldedthebirthofthreemodernnations.OnewasCanadawhichre__iveditsfirstlargeinfluxofEnglish-speakingpopulationfromthethousandsofloyalistswhofledtherefromtheUnitedStates.AnotherwasAustraliawhichbecameapenalcolonynowthatAmericawasnolonger__ailableforprisonersanddebtors.Thethirdnewcomer-theUnitedStates-baseditselfsquarelyonrepublicanprinciples.Yeteventhepoliticaloverturnwasnotsorevolutionaryasonemightsuppose.InsomestatesnotablyConnecticutandRhodeIslandthewarlargelyratifiedacolonialself-rulealreadyexisting.Britishofficialseverywhereoustedwererepla__dbyahome-growngoverningclasswhichpromptlysoughtalocalsubstituteforkingandParliament.09SuburbanizationIfbysuburbismeantanurban__rginthatgrowsmorerapidlythanitsalreadydevelopedinteriorthepro__ssofsuburbanizationbeganduringtheemergen__oftheindustrialcityinthesecondquarterofthenineteenth__ntury.Beforethatperiodthecitywasa__allhighlycompactclusterinwhichpeoplemovedaboutonfootandgoodswereconveyedbyhorseandcart.Buttheearlyfactoriesbuiltinthe1840’swerelocatedalongwaterwaysandnearrailheadsattheedgesofcitiesandhousingwasneededforthethousandsofpeopledrawnbytheprospectofemployment.Intimethefactoriesweresurroundedbyproliferatingmilltownsofapartmentsandrowhousesthatabuttedtheolder__incities.Asadefenseagainstthisencroachmentandtoenlargetheirtaxbasesthecitiesappropriatedtheirindustrialnei___ors.In1854forexamplethecityofPhiladelphiaannexedmostofPhiladelphiaCounty.Similarmunicipal__neuverstookpla__inChicagoandinNewYork.IndeedmostgreatcitiesoftheUnitedStatesachievedsuchstatusonlybyincorporatingthecommunitiesalongtheirborders.Withtheac__lerationofindustrialgrowthcameacuteurbancrowdingandaccompanyingsocialstress-conditionsthatbegantoapproachdisastrousproportionswhenin1888thefirstcommerciallysuc__ssfulelectrictractionlinewasdeveloped.Withinafewyearsthehorse-drawntrolleyswereretiredandelectricstreetcarnetworkscrisscrossedandconnectedevery__jorurbanareafosteringaw__eofsuburbanizationthattransformedthecompactindustrialcityintoadispersedmetropolis.Thisfirstphaseof__ss-scalesuburbanizationwasreinfor__dbythesimultaneousemergen__oftheurbanMiddleClasswhosedesiresforhomeownershipinnei___orhoodsfarfromtheaginginnercityweresatisfiedbythedevelopersofsingle-familyhousingtracts.10TypesofSpeechStandardusageincludesthosewordsandexpressionsunderstoodusedandac__ptedbya__jorityofthespeakersofalanguageinanysituationregardlessoftheleveloffor__lity.Assuchthesewordsandexpressionsarewelldefinedandlistedinstandarddictionaries.Colloquiali__sontheotherhandarefamiliarwordsandidiomsthatareunderstoodbyalmostallspeakersofalanguageandusedininfor__lspeechorwritingbutnotconsideredappropriateformorefor__lsituations.Almostallidio__ticexpressionsarecolloquiallanguage.Slanghoweverreferstowordsandexpressionsunderstoodbyalargenumberofspeakersbutnotac__ptedasgoodfor__lusagebythe__jority.Colloquialexpressionsandevenslang__ybefoundinstandarddictionariesbutwillbesoidentified.Bothcolloquialusageandslangaremorecommoninspeechthaninwriting.Colloquialspeechoftenpassesintostandardspeech.Someslangalsopassesintostandardspeechbutotherslangexpressionsenjoymomentarypopularityfollowedbyobscurity.Insomecasesthe__jorityneverac__pts__rtainslangphrasesbutneverthelessretainsthemintheircollectivememories.Everygenerationseemstorequireitsownsetofwordstodescribefamiliaro__ectsandevents.Ithasbeenpointedoutbyanumberoflinguiststhatthreeculturalconditionsarene__ssaryforthecreationofalargebodyofslangexpressions.Firsttheintroductionandac__ptan__ofnewo__ectsandsituationsinthesociety;secondadiversepopulationwithalargenumberofsubgroups;thirdassociationamongthesubgroupsandthe__joritypopulation.Finallyitisworthnotingthatthetermsstandardcolloquialandslangexistonlyasabstractlabelsforscholarswhostudylanguage.Onlyatinynumberofthespeakersofanylanguagewillbeawarethattheyareusingcolloquialorslangexpressions.MostspeakersofEnglishwillduringappropriatesituationsselectanduseallthreetypesofexpressions.11ArchaeologyArchaeologyisasour__ofhistorynotjustabumbleauxiliarydiscipline.ArchaeologicaldataarehistoricaldocumentsintheirownrightnotmereillustrationstowrittentextsJustasmuchasanyotherhistoriananarchaeologiststu___sandtriestoreconstitutethepro__ssthathascreatedthehu__nworldinwhichwelive-andusourselvesinsofarasweareeachcreaturesofourageandsocialenviro__ent.Archaeologicaldataareallchangesinthe__terialworldresultingfromhu__nactionormoresuccinctlythefossilizedresultsofhu__nbeh__ior.Thesumtotaloftheseconstituteswhat__ybecalledthearchaeologicalrecord.Thisrecordexhibits__rtainpeculiaritiesanddeficienciestheconsequen__sofwhichprodu__arathersuperficialcontrastbetweenarchaeologicalhistoryandthemorefamiliarkindbaseduponwrittenrecords.Notallhu__nbeh__iorfossilizes.ThewordsIutterandyouhearasvibrationsintheairare__rtainlyhu__nchangesinthe__terialworldand__ybeofgreathistoricalsignifican__.Yettheyle__enosortoftra__inthearchaeologicalrecordsunlesstheyarecapturedbyaDictaphoneorwrittendownbyaclerk.Themovementoftroopsonthebattlefield__ychangethecourseofhistorybutthisisequallyephemeralfromthearchaeologist’sstandpoint.Whatareperhapsworsemostorganic__terialsareperishable.Everything__deofwoodhidewoollinengrasshairandsimilar__terialswilldecayandvanishindustinafewyearsor__nturiess__eunderveryex__ptionalconditions.Inarelativelybriefperiodthearchaeologicalrecordisredu__tomerescrapsofstoneboneglassmetalandearthenware.Stillmodernarchaeologybyapplyingappropriatetechniquesandcomparativemethodsaidedbyafewluckyfindsfrompeat-bogsdesertsandfrozensoilsisabletofillupagooddealofthegap.12MuseumsFromBostontoLosAngelesfromNewYorkCitytoChicagotoDallasmuseumsareeitherplanningbuildingorwrappingupwholesaleexpansionprograms.Theseprogramsalreadyh__eradicallyalteredfacadesandfloorplansorareexpectedtodosointhenot-too-distantfuture.InNewYorkCityalonesix__jorinstitutionsh__espreadupandoutintotheairspa__andnei___orhoodsaroundthemorarepreparingtodoso.Thereasonsforthisconfluen__ofactivityarecomplexbutonefactorisaconsiderationeverywhere-spa__.Withcollectionsexpandingwiththeneedsandfunctionsofmuseumschangingemptyspa__hasbecomeaverypreciouscommodity.ProbablynowhereinthecountryisthismoretruethanatthePhiladelphiaMuseumofArtwhichhasneededadditionalspa__fordecadesandwhichre__iveditslastsignificantfa__lifttenyearsago.Becauseofthespa__crunchtheArtMuseumhasbecomeincreasinglycautiousinconsideringacquisitionsanddonationsofartinsomecasespassingupopportunitiestostrengthenitscollections.Deac__ssing-orsellingoff-worksofarthastakenonnewimportan__becauseofthemuseum’sspa__problems.Andincreasinglycuratorsh__ebeenfor__dtojugglegalleryspa__rotatingone__sterpie__intopublicviewwhileanotherissenttostorage.Despitetheclearneedforadditionalgalleryandstoragespa__howeverthemuseumhasnoplannoplantobreakoutofitsenvelopeinthenextfifteenyearsaccordingtoPhiladelphiaMuseumofArt’spresident.13SkyscrapersandEnviro__entInthelate1960’s__nypeopleinNorthAmericaturnedtheirattentiontoenviro__entalproblemsandnewsteel-and-glassskyscraperswerewidelycriticized.Ecologistspointedoutthataclusteroftallbuildingsinacityoftenoverburdenspublictransportationandparkinglotcapacities.Skyscrapersarealsol__ishconsumersandwastersofelectricpower.Inonere__ntyeartheadditionof17millionsquarefeetofskyscraperoffi__spa__inNewYorkCityraisedthepeakdailyde__ndforelectricityby120000kilowatts-enoughtosupplytheentirecityofAlbanyNewYorkforaday.Glass-walledskyscraperscanbeespeciallywasteful.Theheatlossorgainthroughawallofhalf-inchplateglassismorethantentimesthatthroughatypical__sonrywallfilledwithinsulationboard.Tolessenthestrainonheatingandair-conditioningequipmentbuildersofskyscrapersh__ebeguntousedouble-glazedpanelsofglassandreflectiveglassescoatedwithsilverorgoldmirrorfilmsthatredu__glareaswellasheatgain.Howevermirror-walledskyscrapersraisethetemperatureofthesurroundingairandaffectnei___oringbuildings.Skyscrapersputaseverestrainonacity’ssanitationfacilitiestoo.IffullyoccupiedthetwoWorldTrade__ntertowersinNewYorkCitywouldalonegenerate
2.25milliongallonsofrawsewageeachyear-asmuchasacitythesizeofStanfordConnecticutwhichhasapopulationofmorethan
109000.14ARareFossilRecordThepreservationofembryosandjuvenilesisarateoccurren__inthefossilrecord.Thetinydelicateskeletonsareusuallyscatteredbysc__engersordestroyedbyweatheringbeforetheycanbefossilized.Ichthyosaurshadahigherchan__ofbeingpreservedthandidterrestrialcreaturesbecauseas__rineani__lstheytendedtoliveinenviro__entslesssu__ecttoerosion.Stilltheirfossilizationrequiredasuiteoffactors:aslowrateofdecayofsofttissueslittlesc__engingbyotherani__lsalackofswiftcurrentsandw__estojumbleandcarryaway__allbonesandfairlyrapidburial.Giventhesefactorssomeareash__ebecomeatreasuryofwell-preservedichthyosaurfossils.ThedepositsatHolzmadenGermanypresentaninterestingcasefor____ysis.Theichthyosaurre__insarefoundinblackbituminous__rineshalesdepositedabout190millionyearsago.Overtheyearsthousandsofspecimensof__rinereptilesfishandinvertebratesh__ebeenrecoveredfromtheserocks.Thequalityofpreservationisoutstandingbutwhatisevenmoreimpressiveisthenumberofichthyosaurfossilscontainingpreservedembryos.Ichthyosaurswithembryosh__ebeenreportedfrom6differentlevelsoftheshaleina__allareaaroundHolz__densuggestingthataspecificsitewasusedbylargenumbersofichthyosaursrepeatedlyovertime.Theembryosarequiteadvan__dintheirphysicaldevelopment;theirpaddlesforexamplearealreadywellformed.Onespecimenisevenpreservedinthebirthc____.Inadditiontheshalecontainsthere__insof__nynewbornsthatarebetween20and30incheslong.Whyarethereso__nypregnantfe__lesandyoungatHolz__denwhentheyaresorareelsewhereThequalityofpreservationisalmostun__tchedandquarryoperationsh__ebeencarriedoutcarefullywithanawarenessofthevalueofthefossils.Butthesefactorsdonotaccountfortheinterestingquestionofhowtherecametobesuchacon__ntrationofpregnantichthyosaursinaparticularpla__veryclosetotheirtimeofgivingbirth.15TheNobelAcademyForthelast82yearsSweden’sNobelAcademyhasdecidedwhowillre__ivetheNobelPrizeinLiteraturetherebydeterminingwhowillbeelevatedfromthegreatandtheneargreattotheimmortal.ButtodaytheAcademyiscomingunderhe__ycritici__bothfromthewithoutandfromwithin.CriticscontendthattheselectionofthewinnersoftenhaslesstodowithtruewritingabilitythanwiththepeculiarinternalpoliticsoftheAcademyandofSwedenitself.AccordingtoIng__r__orkstentheculturaleditorforoneofthecountry’stwo__jornewspaperstheprizecontinuestorepresentwhatpeoplecallaverySwedishexercise:reflectingSwedishtastes.TheAcademyhasdefendeditselfagainstsuchchargesofprovinciali__initsselectionbyassertingthatitsphysicaldistan__fromthegreatliterarycapitalsoftheworldactuallyservestoprotecttheAcademyfromoutsideinfluen__s.This__ywellbetruebutcriticsrespondthatthisverydistan____yalsoberesponsiblefortheAcademy’sinabilitytoper__iveaccuratelyauthentictrendsintheliteraryworld.Regardlessofcon__rnsovertheselectionpro__sshoweveritseemsthattheprizewillcontinuetosurvivebothasanindicatoroftheliteraturethatwemosthighlypraiseandasanelusivegoalthatwritersseek.Iffornootherreasontheprizewillcontinuetobedesirableforthefinancialrewardsthataccompanyit;notonlyisthecashprizeitselfconsiderablebutitalsodra__ticallyincreasessalesofanauthor’sbooks.
16.thewarbetweenBritainandFranceInthelateeighteenth__nturybattlesragedinalmosteverycornerofEuropeaswellasintheMiddleEastSouthAfricatheWestIn___sandLatinAmerica.Inrealityhowevertherewasonlyone__jorwarduringthistimethewarbetweenBritainandFrance.Allotherbattleswereancillarytothislargerconflictandwereoftenatleastpartiallyrelatedtoitsantagonist’goalsandstrategies.FrancesoughttotaldominationofEurope.ThisgoalwasobstructedbyBritishindependen__andBritain’seffortsthroughoutthecontinenttothwartNapoleon;throughtreaties.Britainbuiltcoalitionsnotdissimilarincon__pttotoday’sNATOguaranteeingBritishparticipationinall__jorEuropeanconflicts.Thesetwoantagonistswerepoorly__tchedinsofarastheyhadveryunequalstrengths;FrancewaspredominantonlandBritainatsea.TheFrenchknewthatshortofdefeatingtheBritishn__ytheironlyhopeofvictorywastoclosealltheportsofEuropetoBritishships.AccordinglyFrancesetouttoovercomeBritainbyextendingitsmilitarydominationfromMoscowtLisbonfromJutlandtoCaldaria.AllofthisentailedtremendousriskbecauseFrancedidnoth__ethemilitaryresour__stocontrolthismuchterritoryandstillprotectitselfand__intainorderathome.Frenchstrategistscalculatedthatan__yof150shipswouldprovidethefor__ne__ssarytodefeattheBritishn__y.Suchafor__wouldgiveFranceathree-to-twoadvantageoverBritain.Thisadvantagewasdeemedne__ssarybecauseofBritain’ssuperiorseaskillsandtechnologybecauseofBritain’ssuperiorseaskillsandtechnologyandalsobecauseBritainwouldbefightingadefensivewarallowingittowinwithfewerfor__s.NapoleonneverlostsubstantialimpedimenttohiscontrolofEurope.Ashisfor__nearedthatgoalNapoleongrewincreasinglyimpatientandbeganplanninganimmediateattack.17EvolutionofsleepSleepisveryancient.Intheelectroen__phalographicsenseweshareitwithallthepri__tesandalmostalltheother__m__lsandbirds:it__yextendbackasfarasthereptiles.Thereissomeeviden__thatthetwotypesofsleepdreaminganddreamlessdependonthelife-styleoftheani__landthatpredatorsarestatisticallymuchmorelikelytodreamthanpreywhichareinturnmuchmorelikelytoexperien__dreamlesssleep.Indreamsleeptheani__lispowerfullyimmobilizedandre__rkablyunresponsivetoexternalstimuli.Dreamlesssleepismuchshallowerandweh__eallwitnessedcatsordogscockingtheirearstoasoundwhenapparentlyfastasleep.Thefactthatdeepdreamsleepisrareamongpraytodayseemsclearlytobeaproductofnaturalselectionandit__kessensethattodaywhensleepishighlyevolvedthestupidani__lsarelessfrequentlyimmobilizedbydeepsleepthanthe__artones.ButwhyshouldtheysleepdeeplyatallWhyshouldastateofsuchdeepimmobilizationeverh__eevolvedPerhapsoneusefulhintabouttheoriginalfunctionofsleepistobefoundinthefactthatdolphinsandwhalesandaquatic__m__lsingeneraseemtosleepverylittle.Thereisbyandlargenopla__tohideintheo__an.Coulditbethatratherthanincreasinganani__l’svulnerabilitytheUniversityofFloridaandRayMid___sofLondonUniversityh__esuggestedthistobethecase.Itiscon__ivablethatani__lswhoaretoostupidtobequiteontheirowninitiativeareduringperiodsofhighriskimmobilizedbytheimplacablearmofsleep.Thepointseemsparticularlyclearfortheyoungofpredatoryani__ls.Thisisaninterestingnotionandprobablyatleastpartlytrue.18ModernAmericanUniversitiesBeforethe1850’stheUnitedStateshadanumberof__allcollegesmostofthemdatingfromcolonialdays.Theywere__allchurchconnectedinstitutionswhosepri__rycon__rnwastoshapethemoralcharacteroftheirstudents.ThroughoutEuropeinstitutionsofhigherlearninghaddevelopedbearingtheancientnameofuniversity.InGer__nuniversitywascon__rnedpri__rilywithcreatingandspreadingknowledgenotmorals.Betweenmid-__nturyandtheendofthe1800’smorethanninethousandyoungAmericansdissatisfiedwiththeirtrainingathomewenttoGermanyforadvan__dstudy.Someofthemreturntobecomepresidentsofvenerablecolleges-----HarvardYaleColumbia---andtransformthemintomodernuniversities.Thenewpresidentsbrokealltieswiththechurchesandbroughtinanewkindoffaculty.Professorswerehiredfortheirknowledgeofasu__ectnotbecausetheywereoftheproperfaithandhadastrongarmfordiscipliningstudents.Thenewprinciplewasthatauniversitywastocreateknowledgeaswellaspassitonandthiscalledforafacultycomposedofteacher-scholars.Drillingandlearningbyrotewererepla__dbytheGer__nmethodoflecturinginwhichtheprofessor’sownresearchwaspresentedinclass.GraduatetrainingleadingtothePh.D.anancientGer__ndegreesignifyingthehighestlevelofadvan__dscholarlyattai__entwasintrodu__d.Withtheestablishmentoftheseminarsystemgraduatestudentlearnedtoquestion____yzeandconducttheirownresearch.Atthesametimethenewuniversitygreatlyexpandedinsizeandcourseofferingsbreakingcompletelyoutoftheoldconstrictedcurriculumof__the__ticsclassicsrhetoricandmusic.ThepresidentofHarvardpioneeredtheelectivesystembywhichstudentswereabletochoosetheirowncourseofstudy.Thenotionof__jorfieldsofstudyemerged.Thenewgoalwasto__ketheuniversityrelevanttotherealpursuitsoftheworld.Payingcloseheedtothepracticalneedsofsocietythenewuniversitiestrainedmenandwomentoworkatitstaskswithengineeringstudentsbeingthemostcharacteristicofthenewregime.Studentswerealsotrainedaseconomistsarchitectsagriculturalistssocialwelfareworkersandteachers.19children’snumericalskillsPeopleappeartoborntocompute.Thenumericalskillsofchildrendevelopsoearlyandsoinexorablythatitiseasytoi__gineaninternalclockof__the__tical__turityguidingtheirgrowth.Notlongafterlearningtowalkandtalktheycansetthetablewithimpressaccuracy---oneknifeonespoononeforkforeachofthefivechairs.Soontheyarecapableofnothingthattheyh__epla__dfiveknivesspoonsandforksonthetableandabitlaterthatthisamountstofifteenpie__sofsilverware.H__ingthus__steredadditiontheymoveontosubtraction.Itseemsalmostreasonabletoexpectthatifachildweresecludedonadesertislandatbirthandretrievedsevenyearslaterheorshecouldenterasecondenterasecond-grade__the__ticsclasswithoutanyseriousproblemsofin____ectualadjustment.Ofcoursethetruthisnotso______.This__nturytheworkofcognitivepsychologistshasilluminatedthesubtleformsofdailylearningonwhichin____ectualprogressdepends.Childrenwereobservedastheyslowlygrasped-----orasthecasemightbebumpedinto-----con__ptsthat_____stakeforquantityisunchangedaswaterpoursfromashortglassintoatallthinone.Psychologistsh__esin__demonstratedthatyoungchildrenaskedtocountthepencilsinapilereadilyreportthenumberofblueorredpencilsbutmustbecoaxedintofindingthetotal.Suchstu___sh__esuggestedthattherudimentsof__the__ticsare__steredgraduallyandwitheffort.Theyh__ealsosuggestedthattheverycon__ptofabstractnumbers------theideaofaonenessatwonessathreenessthatappliestoanyclassofo__ectsandisaprerequisitefordoinganythingmore__the__ticallyde__ndingthansettingatable-----isitselffarfrominnate20TheHistoricalSignifican__ofAmericanRevolutionThewaysofhistoryaresointricateandthemotivationsofhu__nactionssocomplexthatitisalwayshazardoustoattempttorepresenteventscoveringanumberofyearsamultiplicityofpersonsanddistantlocalitiesastheexpressionofonein____ectualorsocialmovement;yetthehistoricalpro__sswhichculminatedintheas__ntofTho__sJeffersontothepresidencycanberegardedastheoutstandingexamplenotonlyofthebirthofanewwayoflifebutofnationali__asanewwayoflife.TheAmericanRevolutionrepresentsthelinkbetweentheseventeenth__nturyinwhichmodernEnglandbecameconsciousofitselfandtheawakeningofmodernEuropeattheendoftheeighteenth__ntury.It__yseemstrangethatthe__rchofhistoryshouldh__ehadtocrosstheAtlanticOceanbutonlyintheNorthAmericancoloniescouldastruggleforciviclibertyleadalsotothefoundationofanewnation.Hereinthepopularrisingagainsta“tyrannical”gover__entthefruitsweremorethanthesecuringofafreerconstitution.Theyincludedthegrowthofanationborninlibertybythewillofthepeoplenotfromtherootsofcommondes__ntageographicentityortheambitionsofkingordynasty.WiththeAmericannationforthefirsttimeanationwasbornnotinthedimpastofhistorybutbeforetheeyesofthewholeworld.21TheOriginofSportsWhendidsportbeginIfsportisinessen__playtheclaimmightbe__dethatsportismucholderthanhu__nkindforasweallh__eobservedthebeastsplay.Dogsandcatswrestleandplayballgames.Fishesandbirdsdan__.Theapesh__e______pleasurablegames.Frolickinginfantsschoolchildrenplayingtagand_____armwrestlersaredemonstratingstrongtransgenerationalandtransspeciesbondswiththeuniverseofani__ls-pastpresentandfuture.Youngani__lsparticularlytumblechaserunwrestlemockimitateandlaughorsoitseemstothepointofdelightedexhaustion.Theirplayandoursappearstoservenootherpurposethantogivepleasuretotheplayersandapparentlytoremoveustemporarilyfromtheanguishoflifeinearnest.Somephilosophersh__eclaimedthatourplayfulnessisthemostnoblepartofourbasicnature.Intheirgenerouscon__ptionsplayharmlesslyandexperimentallypermitsustoputourcreativefor__sfantasyandi__ginationintoaction.Playisreleasefromthetediousbattlesagainstscarcityanddeclinewhicharethein__ssantandinevitabletrage___soflife.Thisisagrandcon__ptionthatexcitesandprovokes.Theholdersofthisviewclaimthattheoriginsofourhighestaccomplishments----liturgyliteratureandlaw----canbetra__dtoaplayimpulsewhichparadoxicallyweseemostpurelyenjoyedbyyoungbeastsandchildren.Oursportsinthisratherhappynonfatalisticviewofhu__nnaturearemoresplendidcreationsofthenondatabletransspeciesplayimpulse.
22.CollectiblesCollectiblesh__ebeenapartofalmosteveryculturesin__ancienttimes.Whereassomeo__ectsh__ebeencollectedfortheirusefulnessothersh__ebeenselectedfortheiraestheticbeautyalone.IntheUnitedStatesthekindsofcollectiblescurrentlypopularrangefromtraditionalo__ectssuchasstampscoinsrarebooksandarttomorere__ntitemsofinterestlikedollsbottlesbaseballcardsandcomicbooks.Interestincollectibleshasincreasedenormouslyduringthepastdecadeinpartbecausesomecollectiblesh__edemonstratedtheirvalueasinvestments.Especiallyduringcyclesofhighinflationinvestorstrytopurchasetangiblesthatwillatleastretaintheircurrent__rketvalues.Ingeneralthemosttraditionalcollectibleswillbesoughtbecausetheyh__epreservedtheirvalueovertheyearsthereisanorganizedauction__rketforthemandtheyaremosteasilysoldintheeventthatcashisneeded.Someexamplesofthemoststablecollectiblesareold__stersChinese__ramicsstampscoinsrarebooksantiquejewelrysilverpor__lainartbywell-knownartistsautographsandperiodfurniture.Otheritemsofmorere__ntinterestincludeoldphotographrecordsold__gazinespostcardsbaseballcardsartglassdollsclassiccarsoldbottlesandcomicbooks.Theserelativelynewkindsofcollectibles__yactuallyappreciatefasterasshort-terminvestmentsbut__ynotholdtheirvalueaslong-terminvestments.On__acollectiblehashaditsinitialplayitappreciatesatafairlysteadyratesupportedbyanincreasingnumberofenthusiasticcollectorscompetingforthelimitedsupplyofcollectiblesthatbecomeincreasinglymoredifficulttolocate.23FordAlthoughHenryFord’snameiscloselyassociatedwiththecon__ptof__ssproductionheshouldre__iveequalcreditforintroducinglaborpracti__sasearlyas1913thatwouldbeconsideredadvan__devenbytoday’sstandards.Safetymeasureswereimprovedandtheworkdaywasredu__dtoeighthourscomparedwiththeten-ortwelve-hourdaycommonatthetime.Inordertoaccommodatetheshorterworkdaytheentirefactorywasconvertedfromtwotothreeshifts.Inadditionsickle__esaswellasimprovedmedicalcareforthoseinjuredonthejobwereinstituted.TheFordMotorCompanywasoneofthefirstfactoriestodevelopatechnicalschooltotrainspecializedskilledlaborersandanEnglishlanguageschoolforimmigrants.Someeffortswereeven__detohirethehandicappedandprovidejobsforformerconvicts.Themostwidelyacclaimedinnovationwasthefive-dollar-a-dayminimumwagethatwasofferedinordertorecruitandretainthebestmechanicsandtodiscouragethegrowthoflaborunions.Fordexplainedthenewwagepolicyintermsofefficiencyandprofitsharing.Healsomentionedthefactthathisemployeeswouldbeabletopurchasetheautomobilesthattheyprodu__d-ineffectcreatinga__rketfortheproduct.Inordertoqualifyfortheminimumwageanemployeehadtoestablishade__nthomeanddemonstrategoodpersonalhabitsincludingsobrietythriftinessindustriousnessanddependability.Althoughsomecritici__wasdirectedatFordforinvolvinghimselftoomuchinthepersonallivesofhisemployeestherecanbenodoubtthatatatimewhenimmigrantswerebeingtakenadvantageofinfrightfulwaysHenryFordwashelping__nypeopletoestablishthemselvesinAmerica.24PianoThean__stryofthepianocanbetra__dtotheearlykeyboardinstrumentsofthefifteenthandsixteenth__nturies---thespinetthedulcimerandthevirginal.Intheseventeenth__nturytheorganthecl__ichordandtheharpsichordbecamethechiefinstrumentsofthekeyboardgroupasupre__cythey__intaineduntilthepianosupplantedthemattheendoftheeighteenth__ntury.Thecl__ichord’stonewasmetallicandneverpowerful;neverthelessbecauseofthevarietyoftonepossibletoit__nycomposersfoundthecl__ichordasympatheticinstrumentforinti__techambermusic.Theharpsichordwithitsbrightvigoroustonewasthef__oriteinstrumentforsupportingthebassofthe__allorchestraoftheperiodandforcon__rtusebutthecharacterofthetonecouldnotbevarieds__ebymechanicalorstructuraldevi__s.Thepianowasperfectedintheearlyeighteenth__nturybyaharpsichord__kerinItalythoughmusicologistspointoutseveralpreviousinstan__softheinstrument.Thisinstrumentwascalledapianoefortesortandloudtoindicateitsdynamicversatility;itsstringswerestruckbyarecoilinghammerwithafelt-paddedhead.Thewiresweremuchhe__ierintheearlierinstruments.Aseriesofmechanicalimprovementscontinuingwellintothenineteenth__nturyincludingtheintroductionofpedalstosustaintoneortosoftenittheperfectionofametalframeandsteelwireofthefinestqualityfinallyprodu__daninstrumentcapableofmyriadtonaleffectsfromthemostdelicateharmoniestoanalmostorchestralfullnessofsoundfromaliquidsingingtonetoasharppercussivebrillian__.
25.MovieMusicAccustomedthoughwearetospeakingofthefilms__debefore1927as“silent”thefilmhasneverbeeninthefullsenseofthewordsilent.Fromtheverybeginningmusicwasregardedasanindispensableaccompaniment;whentheLumierefilmswereshownatthefirstpublicfilmexhibitionintheUnitedStatesinFebruary1__6theywereaccompaniedbypianoimprovisationsonpopulartunes.Atfirstthemusicplayedborenospecialrelationshiptothefilms;anaccompanimentofanykindwassufficient.Withinaveryshorttimehowevertheincongruityofplayinglivelymusictoasolemnfilmbecameapparentandfilmpianistsbegantotakesomecarein__tchingtheirpie__stothemoodofthefilm.Asmovietheatersgrewinnumberandimportan__aviolinistandperhapsa__llistwouldbeaddedtothepianistin__rtaincasesandinthelargermovietheaters__allorchestraswereformed.Foranumberofyearstheselectionofmusicforeachfilmprogramrestedentirelyinthehandsoftheconductororleaderoftheorchestraandveryoftentheprincipalqualificationforholdingsuchapositionwasnotskillortastesomuchastheownershipofalargepersonallibraryofmusicalpie__s.Sin__theconductorseldomsawthefilmsuntilthenightbeforetheyweretobeshownifindeedtheconductorwasluckyenoughtoseethemthenthemusicalarrangementwasnor__llyimprovisedinthegreatesthurry.Tohelpmeetthisdifficultyfilmdistributingcompaniesstartedthepracti__ofpublishingsuggestionsformusicalaccompaniments.In1909forexampletheEdisonCompanybeganissuingwiththeirfilmssuchindicationsofmoodas“pleasant”“sad”“lively”.Thesuggestionsbecamemoreexplicitandsoemergedthemusicalcuesheetcontainingindicationsofmoodthetitlesofsuitablepie__sofmusicandprecisedirectionstoshowwhereonepie__ledintothenext.__rtainfilmshadmusicespeciallycomposedforthem.ThemostfamousoftheseearlyspecialscoreswasthatcomposedandarrangedforD.WGriffith’sfilmBirthofaNationwhichwasreleasedin
1915.
26.InternationalBusinessandCross-culturalCommunicationTheincreaseininternationalbusinessandinforeigninvestmenthascreatedaneedforexecutiveswithknowledgeofforeignlanguagesandskillsincross-culturalcommunication.Americanshoweverh__enotbeenwelltrainedineitherareaandconsequentlyh__enotenjoyedthesamelevelofsuc__ssinnegotiationinaninternationalarenaash__etheirforeigncounterparts.Negotiatingisthepro__ssofcommunicatingbackandforthforthepurposeofreachinganagreement.Itinvolvespersuasionandcompromisebutinordertoparticipateineitheronethenegotiatorsmustunderstandthewaysinwhichpeoplearepersuadedandhowcompromiseisreachedwithinthecultureofthenegotiation.In__nyinternationalbusinessnegotiationsabroadAmericansareper__ivedaswealthyandimpersonal.ItoftenappearstotheforeignnegotiatorthattheAmericanrepresentsalargemulti-million-dollarcorporationthatcanaffordtopaythepri__withoutbargainingfurther.TheAmericannegotiator’srolebecomesthatofanimpersonalpurveyorofinfor__tionandcash.Instu___sofAmericannegotiatorsabroadseveraltraitsh__ebeenidentifiedthat__yservetoconfirmthisstereotypicalper__ptionwhileunderminingthenegotiator’sposition.Twotraitsinparticularthatcausecross-culturalmisunderstandingaredirectnessandimpatien__onthepartoftheAmericannegotiator.FurthermoreAmericannegotiatorsofteninsistonrealizingshort-termgoals.Foreignnegotiatorsontheotherhand__yvaluetherelationshipestablishedbetweennegotiatorsand__ybewillingtoinvesttimeinitforlong-termbenefits.Inordertosolidifytherelationshipthey__yoptforindirectinteractionswithoutregardforthetimeinvolvedingettingtoknowtheothernegotiator.
27.ScientificTheoriesInscien__atheoryisareasonableexplanationofobservedeventsthatarerelated.Atheoryofteninvolvesani__ginarymodelthathelpsscientistspicturethewayanobservedeventcouldbeprodu__d.Agoodexampleofthisisfoundinthekineticmoleculartheoryinwhichgasesarepicturedasbeing__deupof__ny__allparticlesthatareinconstantmotion.Ausefultheoryinadditiontoexplainingpastobservationshelpstopredicteventsthath__enotasyetbeenobserved.Afteratheoryhasbeenpublicizedscientistsdesignexperimentstotestthetheory.Ifobservationsconfirmthescientist’spredictionsthetheoryissupported.Ifobservationsdonotconfirmthepredictionsthescientistsmustsearchfurther.There__ybeafaultintheexperimentorthetheory__yh__etoberevisedorrejected.Scien__involvesi__ginationandcreativethinkingaswellascollectinginfor__tionandperformingexperiments.Factsbythemselvesarenotscien__.Asthe__the__ticianJulesHenriPoincaresaid“Scien__isbuiltwithfactsjustasahouseisbuiltwithbricksbutacollectionoffactscannotbecalledscien__anymorethanapileofbrickscanbecalledahouse.”Mostscientistsstartaninvestigationbyfindingoutwhatotherscientistsh__elearnedaboutaparticularproblem.Afterknownfactsh__ebeengatheredthescientistcomestothepartoftheinvestigationthatrequiresconsiderablei__gination.Possiblesolutionstotheproblemareformulated.Thesepossiblesolutionsarecalledhypotheses.Inawayanyhypothesisisaleapintotheunknown.Itextendsthescientist’sthinkingbeyondtheknownfacts.Thescientistplansexperimentsperformscalculationsand__kesobservationstotesthypotheses.Withouthypothesisfurtherinvestigationlackspurposeanddirection.Whenhypothesesareconfirmedtheyareincorporatedintotheories.28ChangingRolesofPublicEducationOneofthemostimportantsocialdevelopmentsthathelpedto__kepossibleashiftinthinkingabouttheroleofpubliceducationwastheeffectofthebabyboomofthe1950’sand1960’sontheschools.Inthe1920’sbutespeciallyintheDepressionconditionsofthe1930’stheUnitedStatesexperien__dadecliningbirthrate---everythousandwomenagedfifteentoforty-fourg__ebirthtoabout118livechildrenin
192089.2in
193075.8in1936and80in
1940.WiththegrowingprosperitybroughtonbytheSecondWorldWarandtheeconomicboomthatfollowedityoungpeople__rriedandestablishedhouseholdsearlierandbegantoraiselargerfamiliesthanhadtheirprede__ssorsduringtheDepression.Birthratesroseto102perthousandin
1946106.2in1950and118in
1955.Althougheconomicswasprobablythemostimportantdeterminantitisnottheonlyexplanationforthebabyboom.Theincreasedvaluepla__dontheideaofthefamilyalsohelpstoexplainthisriseinbirthrates.Thebabyboomersbeganstreamingintothefirstgradebythemid1940’sandbecameafloodby
1950.Thepublicschoolsystemsuddenlyfounditselfovertaxed.Whilethenumberofschoolchildrenrosebecauseofwartimeandpostwarconditionsthesesameconditions__detheschoolsevenlesspreparedtocopewiththefood.Thewartimeeconomymeantthatfewnewschoolswerebuiltbetween1940and
1945.Moreoverduringthewarandintheboomtimesthatfollowedlargenumbersofteacherslefttheirprofessionforbetter-payingjobselsewhereintheeconomy.Thereforeinthe1950’sand1960’sthebabyboomhitanantiquatedandinadequateschoolsystem.Consequentlythe“custodialrhetoric”ofthe1930’sandearly1940’snolonger__desensethatiskeepingyouthsagedsixteenandolderoutofthelabor__rketbykeepingtheminschoolcouldnolongerbeahighpriorityforaninstitutionunabletofindspa__andstafftoteachyoungerchildrenagedfivetosixteen.Withthebabyboomthefocusofeducatorsandoflaymeninterestedineducationinevitablyturnedtowardthelowergradesandbacktobasicacademicskillsanddiscipline.Thesystemnolongerhadmuchinterestinofferingnontraditionalnewandextraservi__stoolderyouths.29TelecommutingTelecommuting--substitutingthecomputerforthetriptothejob----hasbeenhailedasasolutiontoallkindsofproblemsrelatedtooffi__work.Forworkersitpromises_______fromtheoffi__lesstimewastedintrafficandhelpwithchild-careconflicts.For__nagementtelecommutinghelpskeephighperformersonboardminimizestardinessandabsenteei__byeliminatingcommutesallowsperiodsofsolitudeforhigh-con__ntrationtasksandprovidessche____ngflexibility.InsomeareassuchasSouthernCaliforniaandSeattleWashingtonlocalgover__entsareencouragingcompaniestostarttelecommutingprogramsinordertoredu__rush-hourcongestionandimproveairquality.Butthesebenefitsdonotcomeeasily.__kingatelecommutingprogramworkrequirescarefulplanningandanunderstandingofthedifferen__sbetweentelecommutingrealitiesandpopulari__ges.__nyworkersaresedu__dbyrosyillusionsoflifeasatelecommuter.AcomputerprogrammerfromNewYorkCitymovestothetranquilAdirondackMountainsandstaysincontactwithheroffi__viacomputer.A__nagercomesintohisoffi__threedaysaweekandworksathometheothertwo.Anaccountantstayshometocareforhersickchild;shehooksuphertelephonemodernconnectionsanddoesoffi__workbetweencallstothedoctor.Thesearepowerfuli__gesbuttheyarealimitedreflectionofreality.Telecommutingworkerssoonlearnthatitisalmostimpossibletocon__ntrateonworkandcareforayoungchildatthesametime.Beforea__rtainageyoungchildrencannotrecognizemuchlessrespectthene__ssaryboundariesbetweenworkandfamily.Additionalchildsupportisne__ssaryiftheparentistogetanyworkdone.__nagementtoomustseparatethemythfromthereality.Althoughthemediahaspaidagreatdealofattentiontotelecommutinginmostcasesitistheemployee’ssituationnotthe__ailabilityoftechnologythatprecipitatesatelecommutingarrangement.Thatispartlywhydespitethewidespreadpresscoveragethenumberofcompanieswithwork-at-homeprogramsorpolicyguidelinesre__ins__all.30TheoriginofRefrigeratorsBythemid-nineteenth__nturytheterm“i__box”hadenteredtheAmericanlanguagebuti__wasstillonlybeginningtoaffectthe___tofordinarycitizensintheUnitedStates.Thei__tradegrewwiththegrowthofcities.I__wasusedinhotelst__ernsandhospitalsandbysomeforward-lookingcitydealersinfreshmeatfreshfishandbutter.AftertheCivilWar1861-1865asi__wasusedtorefrigeratefreightcarsitalsocameintohouseholduse.Evenbefore1880halfofthei__soldinNewYorkPhiladelphiaandBaltimoreandone-thirdofthatsoldinBostonandChicagowenttofamiliesfortheirownuse.Thishadbecomepossiblebecauseanewhouseholdconvenien__thei__boxaprecursorofthemodernrefrigeratorhadbeeninvented.__kinganefficienti__boxwasnotaseasyaswemightnowsuppose.Intheearlynineteenth__nturytheknowledgeofthephysicsofheatwhichwasessentialtoascien__ofrefrigerationwasrudimentary.Thecommonsensenotionthatthebesti__boxwasonethatpreventedthei__frommeltingwasofcoursemistakenforitwasthemeltingofthei__thatperformedthecooling.Neverthelessearlyeffortstoeconomizei__includedwrappingupthei__inblanketswhichkeptthei__fromdoingitsjob.Notuntilneartheendofthenineteenth__nturydidinventorsachievethedelicatebalan__ofinsulationandcirculationneededforanefficienti__box.Butasearlyas1803andingeniousMarylandfarmerTho__sMoorehadbeenontherighttrack.HeownedafarmabouttwentymilesoutsidethecityofWashingtonforwhichthevillageofGeorgetownwasthe__rket__nter.Whenheusedani__boxofhisowndesigntotransporthisbutterto__rkethefoundthatcustomerswouldpassuptherapidlymeltingstuffinthetubsofhiscompe_____stopayapremiumpri__forhisbutterstillfreshandhardinneatone-poundbricks.Oneadvantageofhisi__boxMooreexplainedwasthatfarmerswouldnolongerh__etotr__elto__rketatnightinordertokeeptheirprodu__cool.31BritishColumbiaBritishColumbiaisthethirdlargestCanadianprovin__sbothinareaandpopulation.Itisnearly
1.5timesaslargeasTexasandextends800miles1280kmnorthfromtheUnitedStatesborder.ItincludesCanada’sentirewestcoastandtheislandsjustoffthecoast.MostofBritishColumbiaismountainouswithlongruggedrangesrunningnorthandsouth.Eventhecoastalislandsarethere__insofamountainrangethatexistedthousandsofyearsago.DuringthelastI__Agethisrangewasscouredbyglaciersuntilmostofitwasbeneaththesea.Itspeaksnowshowasislandsscatteredalongthecoast.Thesouthwesterncoastalregionhasahumidmild__rinecli__te.SeawindsthatblowinlandfromthewestarewarmedbyacurrentofwarmwaterthatflowsthroughthePacificOcean.Asaresultwintertemperatures__erageabovefreezingandsummersaremild.Thesewarmwesternwindsalsocarrymoisturefromtheo__an.InlandfromthecoastthewindsfromthePacificmeetthemountainbarriersofthecoastalrangesandtheRockyMountains.Astheyrisetocrossthemountainsthewindsarecooledandtheirmoisturebeginstofallasrain.Onsomeofthewesternslopesalmost200inches500cmofrainfalleachyear.MorethanhalfofBritishColumbiaishe__ilyforested.Onmountainslopesthatre__iveplentifulrainfallhugeDouglasfirsriseintoweringcolumns.Theseforestgiantsoftengrowtobeasmuchas300feet90mtallwithdiametersupto10feet3m.Morelumberisprodu__dfromthesetreesthanfromanyotherkindoftreeinNorthAmerica.Hemlockred__darandbalsamfirareamongtheothertreesfoundinBritishColumbia.32BotanyBotanythestudyofplantsoccupiesapeculiarpositioninthehistoryofhu__nknowledge.For__nythousandsofyearsitwastheonefieldofawarenessaboutwhichhu__nshadanythingmorethanthevaguestofinsights.ItisimpossibletoknowtodayjustwhatourStoneAgean__storsknewaboutplantsbutformwhatwecanobserveofpre-industrialsocietiesthatstillexistadetailedlearningofplantsandtheirpropertiesmustbeextremelyancient.Thisislogical.Plantsarethebasisofthefoodpyramidforalllivingthingsevenforotherplants.Theyh__ealwaysbeenenormouslyimportanttothewelfareofpeoplenotonlyforfoodbutalsoforclothingweaponstoolsdyesmedicinesshelterandagreat__nyotherpurposes.TribeslivingtodayinthejunglesoftheA__zonrecognizeliterallyhundredsofplantsandknow__nypropertiesofeach.Tothembotanyassuchhasnonameandisprobablynotevenrecognizedasaspecialbranchof“knowledge”atall.Unfortunatelythemoreindustrializedwebecomethefartherawaywemovefromdirectcontactwithplantsandthelessdistinctourknowledgeofbotanygrows.Yeteveryonecomesunconsciouslyonana__zingamountofbotanicalknowledgeandfewpeoplewillfailtorecognizearoseanappleoranorchid.WhenourNeolithican__storslivingintheMiddleEastabout10000yearsagodiscoveredthat__rtaingrassescouldbeharvestedandtheirseedsplantedforricheryieldsthenextseasonthefirstgreatstepinanewassociationofplantsandhu__nswastaken.Grainswerediscoveredandfromthemflowedthe__rvelofagriculture:cultivatedcrops.Fromthenonhu__nswouldincreasinglytaketheirlivingfromthecontrolledproductionofafewplantsratherthangettingalittlehereandalittletherefrom__nyvarietiesthatgrewwild-andtheaccumulatedknowledgeoftensofthousandsofyearsofexperien__andinti__cywithplantsinthewildwouldbegintofadeaway.33PlanktonScatteredthroughtheseasoftheworldarebillionsoftonsof__allplantsandani__lscalledplankton.Mostoftheseplantsandani__lsaretoo__allforthehu__neyetosee.Theydriftaboutlazilywiththecurrentsprovidingabasicfoodfor__nylargerani__ls.Planktonhasbeendescribedastheequivalentofthegrassesthatgrowonthedrylandcontinentsandthecomparisonisanappropriateone.Inpotentialfoodvaluehoweverplanktonfaroutweighsthatofthelandgrasses.Onescientisthasesti__tedthatwhilegrassesoftheworldprodu__about49billiontonsofvaluablecarbohydrateseachyearthesea’splanktongeneratesmorethantwi__asmuch.Despiteitsenormousfoodpotentiallittleeffectwas__deuntilre__ntlytofarmplanktonaswefarmgrassesonland.Now__rinescientistsh__eatlastbeguntostudythispossibilityespeciallyasthesea’sresour__sloomevenmoreimportantasameansoffeedinganexpandingworldpopulation.Nooneyethasseriouslysuggestedthat“plankton-burgers”__ysoonbecomepopulararoundtheworld.Asapossiblefarmedsupplementaryfoodsour__howeverplanktonisgainingconsiderableinterestamong__rinescientists.Onetypeofplanktonthatseemstoh__egreatharvestpossibilitiesisatinyshrimp-likecreaturecalledkrill.Growingtotwoorthreeincheslongkrillprovidesthe__jorfoodforthegreatbluewhalethelargestani__ltoeverinhabittheEarth.Realizingthatthiswhale__ygrowto100feetandweigh150tonsat__turityitisnotsurprisingthateachone34RaisingOystersIntheoysterswereraisedinmuchthesamewayasdirtfarmersraisedto__toes-bytransplantingthem.Firstfarmersselectedtheoysterbedclearedthebottomofoldshellsandotherdebristhenscatteredcleanshellsabout.Nextthey”planted”fertilizedoystereggswhichwithintwoorthreeweekshatchedintolarvae.Thelarvaedrifteduntiltheyattachedthemselvestothecleanshellsonthebottom.Theretheyre__inedandintimegrewintobabyoysterscalledseedorspat.Thespatgrewlargerbydrawinginseawaterfromwhichtheyderivedmicroscopicparticlesoffood.Beforelongfarmersgatheredthebabyoysterstransplantedthemon__moreintoanotherbodyofwatertofattenthemup.Untilre__ntlythesupplyofwildoystersandthosecrudelyfarmedweremorethanenoughtosatisfypeople’sneeds.Buttodaythedelectableseafoodisnolonger__ailableinabundan__.Theproblemhasbecomesoseriousthatsomeoysterbedsh__evanishedentirely.Fortunatelyasfarbackastheearly1900’s__rinebiologistsrealizedthatifnewmeasureswerenottakenoysterswouldbecomeextinctoratbestaluxuryfood.Sotheysetupwell-equippedhatcheriesandwenttowork.Buttheydidnoth__etheproperequipmentortheskilltohandletheeggs.Theydidnotknowwhenwhatandhowtofeedthelarvae.Andtheyknewlittleaboutthepredatorsthatattackandeatbabyoystersbythemillions.Theyfailedbuttheydoggedlykeptatit.Finallyinthe1940’sasignificantbreakthroughwas__de.The__rinebiologistsdiscoveredthatbyraisingthetemperatureofthewatertheycouldindu__oysterstospawnnotonlyinthesummerbutalsointhefallwinterandspring.Latertheydevelopedatechniqueforfeedingthelarvaeandrearingthemtospat.Goingstillfurthertheysuc__ededinbreedingnewstrainsthatwereresistanttodiseasesgrewfasterandlargerandflourishedinwaterofdifferentsalinitiesandtemperatures.Inadditionthecultivatedoysterstastedbetter!35OilRefiningAnimportantnewindustryoilrefininggrewaftertheCivilwar.Crudeoilorpetroleum-adarkthickoozefromtheearth-hadbeenknownforhundredsofyearsbutlittleusehadeverbeen__deofit.Inthe1850’sSamuelM.Kiera__nufacturerinwesternPennsylvaniabegancollectingtheoilfromlocalseepagesandrefiningitintokerosene.Refininglike__eltingisapro__ssofremovingimpuritiesfromaraw__terial.Kerosenewasusedtolightlamps.Itwasacheapsubstituteforwhaleoilwhichwasbecominghardertoget.Soontherewasalargede__ndforkerosene.Peoplebegantosearchfornewsuppliesofpetroleum.ThefirstoilwellwasdrilledbyE.L.Drakearetiredrailroadconductor.In1859hebegandrillinginTitusvillePennsylvania.Thewholeventureseemedsoimpracticalandfoolishthatonlookerscalledit“Drake’sFolly”.Butwhenhehaddrilleddownabout70feet21metersDrakestruckoil.Hiswellbegantoyield20barrelsofcrudeoiladay.NewsofDrake’ssuc__ssbroughtoilprospectorstothes__ne.Bytheearly1860’sthesewildcattersweredrillingfor“blackgold”alloverwesternPennsylvania.TheboomrivaledtheCaliforniagoldrushof1848initsexcitementandWildWestatmosphere.Anditbroughtfarmorewealthtotheprospectorsthananygoldrush.Crudeoilcouldberefinedinto__nyproducts.Forsomeyearskerosenecontinuedtobetheprincipalone.Itwassoldingro__rystoresanddoor-to-door.Inthe1880’srefinerslearnedhowto__keotherpetroleumproductssuchaswaxesandlubricatingoils.Petroleumwasnotthenusedto__kegasolineorheatingoil.36PlateTectonicsandSea-floorSpreadingThetheoryofplatetectonicsdescribesthemotionsofthelithospherethecomparativelyrigidouterlayeroftheEarththatincludesallthecrustandpartoftheunderlying__ntle.Thelithosphereisdividedintoafewdozenplatesofvarioussizesandshapesingeneraltheplatesareinmotionwithrespecttooneanother.Amid-o__anridgeisaboundarybetweenplateswherenewlithospheric__terialisinjectedfrombelow.Astheplatesdivergefromamid-o__anridgetheyslideonamoreyieldinglayeratthebaseofthelithosphere.Sin__thesizeoftheEarthisessentiallyconstantnewlithospherecanbecreatedatthemid-o__anridgesonlyifanequalamountoflithospheric__terialisconsumedelsewhere.Thesiteofthisdestructionisanotherkindofplateboundary:aseductionzone.Thereoneplatedivesundertheedgeofanotherandisreincorporatedintothe__ntle.Bothkindsofplateboundaryareassociatedwithfaultsystemsearthquakesandvolcani__butthekindsofgeologicactivityobservedatthetwoboundariesarequitedifferent.Theideaofsea-floorspreadingactuallypre__dedthetheoryofplatetectonics.Initsoriginalversionintheearly1960’sitdescribedthecreationanddestructionoftheo__anfloorbutitdidnotspecifyrigidlithosphericplates.ThehypothesiswassubstantiatedsoonafterwardbythediscoverythatperiodicreversalsoftheEarth’s__gneticfieldarerecordedintheo__aniccrust.As__g__risesunderthemid-o__anridgeferro__gneticmineralsinthe__g__become__gnetizedinthedirectionofthe__g__become__gnetizedinthedirectionofthegeo__gneticfield.Whenthe__g__coolsandsolidifiesthedirectionandthepolarityofthefieldarepreservedinthe__gnetizedvolcanicrock.Reversalsofthefieldgiverisetoaseriesof__gneticstripesrunningparalleltotheaxisoftherift.Theo__aniccrustthusservesasa__gnetictaperecordingofthehistoryofthegeo__gneticfieldthatcanbedatedindependently;thewidthofthestripesindicatestherateofthesea-floorspreading.37I__bergsI__bergsareamongnature’smostspectacularcreationsandyetmostpeopleh__eneverseenone.Avagueairofmysteryenvelopsthem.Theycomeintobeing-----somewhere------infarawayfrigidwatersamidthunderousnoiseandsplashingturbulen__whichinmostcasesnoonehearsorsees.Theyexistonlyashorttimeandthenslowlywasteawayjustasunnoti__d.O__ectsofsheerestbeautytheyh__ebeencalled.Appearinginanendlessvarietyofshapesthey__ybedazzlinglywhiteorthey__ybeglassybluegreenorpurpletintedfaintlyofindarkerhues.Theyaregra__fulstatelyinspiring-----incalmsunlightseas.Buttheyarealsocalledfrighteninganddangerousandthattheyare----inthenightinthefogandinstorms.Eveninclearweatheroneiswisetostayasafedistan__awayfromthem.Mostoftheirbulkishiddenbelowthewatersotheirunderwaterparts__yextendoutfarbeyondthevisibletop.Alsothey__yrolloverunexpectedlychurningthewatersaroundthem.I__bergsarepartsofglaciersthatbreakoffdriftintothewaterfloataboutawhileandfinallymelt.I__bergsafloattodayare__deofsnowflakesthath__efallenoverlongagesoftime.Theyembodysnowsthatdrifteddownhundredsor__nythousandsorinsomecases__ybeamillionyearsago.Thesnowsfellinpolarregionsandoncoldmountainswheretheymeltedonlyalittleornotatallandsocollectedtogreatdepthsovertheyearsand__nturies.Aseachyear’ssnowaccumulationlayonthesu_____evaporationandmeltingcausedthesnowflakesslowlytolosetheirfeatherypointsandbecometinygrainsofi__.Whennewsnowfellontopoftheoldittooturnedtoicygrains.Soblanketsofsnowandi__grainsmountedlayeruponlayerandwereofsuchgreatthicknessthattheweightoftheupperlayerscompressedthelowerones.Withtimeandpressurefromabovethe__ny__alli__grainsjoinedandchangedtolargercrystalsandeventuallythedeepercrystalsmergedintoasolid__ssofi__.38TopazTopazisahardtransparentmineral.Itisacompoundofaluminumsilicaandfluorine.Gemtopazisvaluable.Jewelerscallthisvarietyofthestone“precioustopaz”.Thebest-knownprecioustopazgemsrangeincolorfromrichyellowtolightbrownorpinkishred.Topazisoneofthehardestgemminerals.Inthemineraltableofhardnessithasaratingof8whichmeansthataknifecannotcutitandthattopazwillscratchquartz.Thegoldenvarietyofprecioustopazisquiteuncommon.Mostoftheworld’stopaziswhiteorblue.Thewhiteandbluecrystalsoftopazarelargeoftenweighingthousandsofcarats.Forthisreasonthevalueoftopazdoesnotdependsomuchonitssizeasitdoeswithdiamondsand__nyotherpreciousstoneswherethevalueincreasesaboutfourtimeswitheachdoublingofweight.Thevalueofatopazislargelydeterminedbyitsquality.Butcolorisalsoimportant:bluetopazforinstan__isoftenirradiatedtodeepenandimproveitscolor.Bluetopazisoftensoldasaqua__rineandavarietyofbrownquartziswidelysoldastopaz.Thequartzismuchlessbrilliantandmoreplentifulthantruetopaz.Mostofitisvarietyofamethyst:thatheathasturnedbrown.39TheSalinityofO__anWatersIfthesalinityofo__anwatersis____yzeditisfoundtovaryonlyslightlyfrompla__topla__.Neverthelesssomeofthese__allchangesareimportant.Therearethreebasicpro__ssesthatcauseachangeino__anicsalinity.Oneoftheseisthesubtractionofwaterfromtheo__anbymeansofevaporation---conversionofliquidwatertowatervapor.Inthis__nnerthesalinityisincreasedsin__thesaltsstaybehind.Ifthisiscarriedtotheextremeofcoursewhitecrystalsofsaltwouldbeleftbehind.Theoppositeofevaporationisprecipitationsuchasrainbywhichwaterisaddedtotheo__an.Heretheo__anisbeingdilutedsothatthesalinityisdecreased.This__yoccurinareasofhighrainfallorincoastalregionswhereriversflowintotheo__an.Thussalinity__ybeincreasedbythesubtractionofwaterbyevaporationordecreasedbytheadditionoffreshwaterbyprecipitationorrunoff.Nor__llyintropicalregionswherethesunisverystrongtheo__ansalinityissomewhathigherthanitisinotherpartsoftheworldwherethereisnotasmuchevaporation.Similarlyincoastalregionswhereriversdilutetheseasalinityissomewhatlowerthaninothero__anicareas.Athirdpro__ssbywhichsalinity__ybealteredisassociatedwiththefor__tionandmeltingofseai__.Whenseawaterisfrozenthedissolved__terialsareleftbehind.Inthis__nnerseawaterdirectly__terialsareleftbehind.Inthis__nnerseawaterdirectlybeneathfreshlyformedseai__hasahighersalinitythanitdidbeforethei__appeared.Ofcoursewhenthisi__meltsitwilltendtodecreasethesalinityofthesurroundingwater.IntheWeddellSeaAntarcticathedensestwaterintheo__ansisformedasaresultofthisfreezingpro__sswhichincreasesthesalinityofcoldwater.Thishe__ywatersinksandisfoundinthedeeperportionsoftheo__ansoftheworld.40Cohesion-tensionTheoryAtmosphericpressurecansupportacolumnofwaterupto10metershigh.Butplantscanmovewatermuchhigher;thesequoiatreecanpumpwatertoitsverytopmorethan100metersabovetheground.Untiltheendofthenineteenth__nturythemovementofwaterintreesandothertallplantswasamystery.Somebotanistshypothesizedthattheliving__llsofplantsactedaspumps.But__nyexperimentsdemonstratedthatthestemsofplantsinwhichallthe__llsarekilledcanstillmovewatertoappreciableheights.Otherexplanationsforthemovementofwaterinplantsh__ebeenbasedonrootpressureapushonthewaterfromtherootsatthebottomoftheplant.Butrootpressureisnotnearlygreatenoughtopushwatertothetopsoftalltrees.Furthermoretheconiferswhichareamongthetallesttreesh__eunusuallylowrootpressures.Ifwaterisnotpumpedtothetopofatalltreeandifitisnotpushedtothetopofatalltreethenwe__yask:howdoesitgetthereAccordingtothecurrentlyac__ptedcohesion-tensiontheorywaterispulledthere.Thepullonarisingcolumnofwaterinaplantresultsfromtheevaporationofwateratthetopoftheplant.Aswaterislostfromthesu_____ofthele__esanegativepressureortensioniscreated.Theevaporatedwaterisrepla__dbywatermovingfrominsidetheplantinunbrokencolumnsthatextendfromthetopofaplanttoitsroots.Thesamefor__sthatcreatesu_____tensioninanysampleofwaterareresponsibleforthe__intenan__oftheseunbrokencolumnsofwater.Whenwaterisconfinedintubesofvery__allborethefor__sofcohesiontheattractionbetweenwatermoleculesaresogreatthatthestrengthofacolumnofwatercompareswiththestrengthofasteelwireofthesamediameter.Thiscohesivestrengthpermitscolumnsofwatertobepulledtogreatheightswithoutbeingbroken.41AmericanblackbearsAmericanblackbearsappearinavarietyofcolorsdespitetheirname.Intheeasternpartoftheirrangemostofthesebrownredorevenyellowcoats.Tothenorththeblackbearisactuallygrayorwhiteincolor.Eveninthesamelitterbothbrownandblackfurredbears__ybeborn.Blackbearsarethe__allestofallAmericanbearsranginginlengthfromfivetosixfeetweighingfromthreehundredtofivehundredpoundstheireyesandearsare__allandtheireyesightandhearingarenotasgoodastheirsenseof__ell.Likeallbearstheblackbearistimidclumsyandrarelydangerousbutifattackedmostcanclimbtreesandcovergroundatgreatspeeds.Whenangryorfrighteneditisaformidableenemy.Blackbearsfeedonle__esherbs.Fruitberriesinsectsfishandevenlargerani__ls.Oneofthemostinterestingcharacteristicsofbearsincludingtheblackbearistheirwintersleep.Unlikesquirrelswoodchucksand__nyotherwoodlandani__lsbearsdonotactuallyhibernate.Althoughthebeardoesnotduringthewintermothssustainingitselffrombodyfatitstemperaturere__insalmostnor__landitbreathesregularlyfourorfivetimesperminute.Mostblackbearslivealoneex__ptduring__tingseason.Theyprefertoliveinc__eshollowlogsordensethickets.AlittleofonetofourcubsisborninJanuaryorFebruaryafteragestationperiodofsixtoninemonthsandtheyre__inwiththeirmotheruntiltheyarefullygrownoraboutoneandahalfyearsold.Blackbearscanliveaslongasthirtyyearsinthewildandevenlongeringamepreservessetasideforthem.42Coal-firedpowerplantsTheinventionoftheincandes__ntlightbulbbyTho__sA.Edisonin1879createdade__ndforacheapreadily__ailablefuelwithwhichtogeneratelargeamountsofelectricpower.Coalseemedtofitthebillanditfueledtheearliestpowerstations.whichweresetupattheendofthenineteenth__nturybyEdisonhimself.Asmorepowerplantswereconstructedthroughoutthecountrytherelian__oncoalincreasedthroughoutthecountrytherelian__oncoalincreased.Sin__theFirstWorldWarcoal-firedpowerplantshadacombinedintheUnitedStateseachyear.In1986suchplantshadacombinedgeneratingcapacityof2__000megawattsandconsumed83per__ntofthenearly900milliontonsofcoalminedinthecountrythatyear.Giventheun__rtaintyinthefuturegrowthofthenearly900milliontonsofcoalminedinthecountrythatyear.Giventheun__rtaintyinthefuturegrowthofnuclearpowerandinthesupplyofoilandnaturalgascoal-firedpowerplantscouldwellprovideupto70per__ntoftheelectricpowerintheUnitedStatesbytheendofthe__ntury.Yetinspiteofthefactthatcoalhaslongbeenasour__ofelectricityand__yre__inonfor__nyyearscoalrepresentsabout80per__ntofUnitedStatesfossil-fuelreservesithasactuallyneverbeenthemostdesirablefossilfuelforpowerplants.Coalcontainslessenergyperunitofweightthanweightthannaturalgasoroil;itisdifficulttotransportanditisassociatedwithahostofenviro__entalissuesamongthemacidrain.Sin__thelate1960’sproblemsofemissioncontrolandwastedisposalh__esharplyredu__dtheappealofcoal-firedpowerplants.Thecostofamelioratingtheseenviro__entproblemsalongwiththerisingcostofbuildingafacilityaslargeandcomplexasacoal-firedpowerplanth__ealso__desuchplantslessattractivefromapurelyeconomicperspective.Changesinthetechnologicalbaseofcoal-firedpowerplantscouldrestoretheirattractivenesshowever.Whereassomeofthesechangesareintended__inlytoincreasetheproductivityofexistingplantscompletelynewtechnologiesforburningcoalcleanlyarealsobeingdeveloped.43StatisticsThereweretwowidelydivergentinfluen__sontheearlydevelopmentofstatisticalmethods.Statisticshadamotherwhowasdedicatedtokeepingorderlyrecordsofgover__entunitsstatesandstatisticscomefromthesameLatinrootstatusandagentle__nlygamblingfatherwhoreliedon__the__ticstoincreasehisskillatplayingtheoddsingamesofchan__.Theinfluen__ofthemotherontheoffspringstatisticsisrepresentedbycountingmeasuringdescribingtabulatingorderingandthetakingof__nsuses-allofwhichledtomoderndescriptivestatistics.Fromtheinfluen__ofthefathercamemoderninferentialstatisticswhichisbasedsquarelyontheoriesofprobability.Describingcollectionsinvolvestabulatingdepictinganddescribingcollectionsofdata.Thesedata__ybequantitativesuchasmeasuresofheightin____igen__orgradelevel------variablesthatarecharacterizedbyanunderlyingcontinuum---orthedata__yrepresentqualitativevariablessuchas___college__jororpersonalitytype.Large__ssesofdatamustgenerallyundergoapro__ssofsum__rizationorreductionbeforetheyarecomprehensible.Descriptivestatisticsisatoolfordescribingorsum__rizingorreducingtocomprehensibleformthepropertiesofanotherwiseunwieldy__ssofdata.Inferentialstatisticsisafor__lizedbodyofmethodsforsolvinganotherclassofproblemsthatpresentgreatofproblemscharacteristicallyinvolvesattemptsto__kepredictionsusingasampleofobservations.Forexampleaschoolsuperintendentwishestodeterminetheproportionofchildreninalargeschoolsystemwhocometoschoolwithoutbreakfasth__ebeenvaccinatedforfluorwhatever.H__ingalittleknowledgeofstatisticsthesuperintendentwouldknowthatitisunne__ssaryandinefficienttoquestioneachchild:theproportionforthesampleofasfewas100children.Thusthepurposeofinferentialstatisticsistopredictoresti__techaracteristicsofapopulationfromaknowledgeofthecharacteristicsofonlyasampleofthepopulation.44ObtainingFreshwaterfromi__bergsThecon__ptofobtainingfreshwaterfromi__bergsthataretowedtopopulatedareasandaridregionsoftheworldwason__treatedasajokemoreappropriatetocartoonsthanreallife.Butnowitisbeingconsideredquiteseriouslyby__nynationsespeciallysin__scientistsh__ewarnedthatthehu__nra__willoutgrowitsfreshwatersupplyfasterthanitrunsoutoffood.Glaciersareapossiblesour__offreshwaterthathasbeenoverlookeduntilre__ntly.Three-quartersoftheEarth’sfreshwatersupplyisstilltiedupinglaciali__areservoirofuntappedfreshwatersoimmensethatitcouldsustainalltheriversoftheworldfor1000years.Floatingontheo__anseveryyearare7659trillionmetrictonsofi__encasedin_____i__bergsthatbreakawayfromthepolari__capsmorethanninetyper__ntofthemfromAntarctica.Hugeglaciersthatstretchovertheshallowcontinentalshelfgivebirthtoi__bergsthroughouttheyear.I__bergsarenotlikeseai__whichisformedwhentheseaitselffreezesrathertheyareformedentirelyonlandbreakingoffwhenglaciersspreadoverthesea.Astheydriftawayfromthepolarregioni__bergssometimesmovemysteriouslyinadirectionoppositetothewindpulledbysubsu_____currents.Becausetheymeltmoreslowlythan__allerpie__sofi__i__bergsh__ebeenknowntodriftasfarnorthas35degreessouthoftheequatorintheAtlanticOcean.Tocorralthemandsteerthemtopartsoftheworldwheretheyareneededwouldnotbetoodifficult.Thedifficultyarisesinothertechnical__tterssuchasthepreventionofrapidmeltinginwarmercli__tesandthefunnelingoffreshwatertoshoreingreatvolume.Butevenifthei__bergslosthalfoftheirvolumeintowingthewatertheycouldprovidewouldbefarcheaperthanthatprodu__dbydesalinizationorremovingsaltfromwater.45Thesour__ofEnergyAsum__ryofthephysicalandchemicalnatureoflifemustbeginnotontheEarthbutintheSun;infactattheSun’svery__nter.Itisherethatistobefoundthesour__oftheenergythattheSunconstantlypoursoutintospa__aslightandheat.Thisenergyislibratedatthe__nteroftheSunasbillionsuponbillionsofnucleiofhydrogenatomscollidewitheachotherandfusetogethertoformnucleiofheliumandindoingsoreleasesomeoftheenergythatisstoredinthenucleiofatoms.TheoutputoflightandheatoftheSunrequiresthatsome600milliontonsofhydrogenbeconvertedintoheliumintheSuneverysecond.ThistheSunhasbeendoingforseveralthousandsofmillionsofyear.ThenuclearenergyisreleasedattheSun’s__nterashigh-energygam__radiationaformofelectro__gneticradiationlikelightandradiow__esonlyofverymuchshorterw__elength.Thisgam__radiationisabsorbedbyatomsinsidetheSuntobereemittedatslightlylongerw__elengths.Thisradiationinitsturnisabsorbedandreemitted.AstheenergyfiltersthroughthelayersofthesolarinterioritpassesthroughtheX-raypartofthespectrumeventuallybecominglight.Atthisstageithasreachedwhatwecallthesolarsu_____andcanescapeintospa__withoutbeingabsorbedfurtherbysolaratoms.Avery__allfractionoftheSun’slightandheatisemittedinsuchdirectionsthatafterpassingunhinderedthroughinterplanetaryspa__ithitstheEarth.46VisionHu__nvisionlikethatofotherpri__teshasevolvedinanarborealenviro__ent.Inthedensecomplexworldofatropicalforestitismoreimportanttoseewellthattodevelopanacutesenseof__ell.Inthecourseofevolutionmembersofthepri__telineh__eacquiredlargeeyeswhilethesnouthasshrunktogivetheeyeanunimpededview.Of__m__lsonlyhu__nsandsomepri__tesenjoycolorvision.Theredflagisblacktothebull.Horsesliveinamonochromeworld.lightvisibletohu__neyeshoweveroccupiesonlyaverynarrowbandinthewholeelectro__gneticspectrum.Ultr__ioletraysareinvisibletohu__nsthoughantsandhoneybeesaresensitivetothem.Hu__nsthoughantsandhoneybeesaresensitivetothem.Hu__nsh__enodirectper__ptionofinfraredraysunliketherattlesnakewhichhasre__ptorstunedintow__elengthslongerthan
0.7micron.Theworldwouldlookeerilydifferentifhu__neyesweresensitivetoinfraredradiation.Theninsteadofthedarknessofnightwewouldbeabletomoveeasilyinastrangeshadowlessworldwhereo__ectsglowedwithvaryingdegreesofintensity.Buthu__neyesex__linotherways.Theyareinfactre__rkablydis__rningincolorgradation.Thecolorsensitivityofnor__lhu__nvisionisrarelysurpassedevenbysophisticatedtechnicaldevi__s.47FolkCulturesAfolkcultureisa__allisolatedcohesiveconservativenearlyself-sufficientgroupthatishomogeneousincustomandra__withastrongfamilyorclanstructureandhighlydevelopedrituals.Orderis__intainedthroughsanctionsbasedinthereligionorfamilyandinterpersonal.Relationshipsarestrong.Traditionisparamountandchangecomesinfrequentlyandslowly.Thereisrelativelylittledivisionoflaborintospecializedduties.Rathereachpersonisexpectedtoperformagreatvarietyoftasksthoughduties__ydifferbetweenthe___es.Mostgoodsarehand__deandsubsisten__economyprevails.Individuali__isweaklydevelopedinfolkculturesasaresocialclasses.UnalteredfolkculturesnolongerexistinindustrializedcountriessuchastheUnitedStatesandCanada.PerhapsthenearestmodernequivalentinAngloAmericaistheAmishaGer__nAmericanfarmingsectthatlargelyrenoun__stheproductsandlabors__ingdevi__softheindustrialage.InAmishareashorsedrawnbuggiesstillserveasalocaltransportationdevi__andthefaithfularenotpermittedtoownautomobiles.TheAmish’s__ntralreligiouscon__ptofDemut“humility”clearlyreflectstheweaknessofindividuali__andsocialclasssotypicaloffolkculturesandthereisacorrespondingstrengthofAmishgroupidentity.RarelydotheAmish__rryoutsidetheirsect.ThereligionavarietyoftheMennonitefaithprovidestheprincipalmechani__for__intainingorder.Bycontrastapopularcultureisalargeheterogeneousgroupoftenhighlyindividualisticandapronoun__d__nyspecializedprofessions.Secularinstitutionsofcontrolsuchasthepoli__andarmytakethepla__ofreligionandfamilyin__intainingorderandamoney-basedeconomyprevails.Becauseofthesecontrasts“popular”__ybeviewedasclearlydifferentfrom“folk”.Thepopularisreplacingthefolkinindustrializedcountriesandin__nydevelopingnations.Folk-__deo__ectsgivewaytotheirpopularequivalentusuallybecausethepopularitemismorequicklyorcheaplyprodu__diseasierortimes__ingtouseorleadsmoreprestigetotheowner.48BacteriabBacteriaareextremely__alllivingthings.Whilewemeasureourownsizesininchesor__ntimetersbacterialsizeismeasuredinmicrons.Onemicronisathousandthofamillimeter:apinheadisaboutamillimeteracross.Rod-shapedbacteriaareusuallyfromtwotofourmicronslongwhileroundedonesaregenerallyonemicronindiameter.Thusifyouenlargedaroundedbacteriumathousandtimesitwouldbejustaboutthesizeofapinhead.An_____hu__n__gnifiedbythesameamountwouldbeoveramile
1.6kilometertall.Evenwithanordinarymicroscopeyoumustlookcloselytoseebacteria.Usinga__gnificationof100timesonefindsthatbacteriaarebarelyvisibleastinyrodsordots.Onecannot__keoutanythingoftheirstructure.Usingspecialstainsonecanseethatsomebacteriah__eattachedtothemw__y-looking“hairs”calledflagella.Othersh__eonlyoneflagellum.Theflagellarotatepushingthebacteriathroughthewater.__nybacterialackflagellaandcannotmoveaboutbytheirownpowerwhileotherscanglidealongoversu_____sbysomelittle-understoodmechani__.Fromthebacteriapointofviewtheworldisaverydifferentpla__fromwhatitistohu__ns.Toabacteriumwaterisasthickasmolassesistous.Bacteriaareso__allthattheyareinfluen__dbythemovementsofthechemicalmoleculesaroundthem.Bacteriaunderthemicroscopeeventhosewithnoflagellaoftenboun__aboutinthewater.Thisisbecausetheycollidewiththewaterymoleculesandarepushedthiswayandthat.Moleculesmovesorapidlythatwithinatenthofasecondthemoleculesroundabacteriah__eallbeenrepla__dbynewones;evenbacteriawithoutflagellaarethusconstantlyexposedtoachangingenviro__ent.49SleepSleetispartofaperson’sdailyactivitycycle.Thereareseveraldifferentstagesofsleepandtheytoooccurincycles.Ifyouarean__eragesleeperyoursleepcycleisasfollows.Whenyoufistdriftoffintoslumberyoureyeswillrollaboutabityoutemperaturewilldropslightlyyourmuscleswillrelaxandyourbreathingwellslowandbecomequiteregular.Yourbrainw__esslowandbecomequiteregular.Yourbrainw__esslowdownabittoowiththealpharhythmofratherfastw__es1sleep.Forthenexthalfhourorsoasyourelaxmoreandmoreyouwilldriftdownthroughstage2andstage3sleep.Theloweryourstageofsleep.Sloweryourbrainw__eswillbe.Thenabout40to69minutesafteryouloseconsciousnessyouwillh__ereachedthedeepestsleepofall.Yourbrainwillshowthelargesloww__esthatareknownasthedeltarhythm.Thisisstage4sleep.Youdonotre__inatthisdeepfourthstageallnightlongbutinsteadabout80minutesafteryoufallintoslumberyourbrainactivitylevelwillincreaseagainslightly.Thedeltarhythmwilldisappeartoberepla__dbytheactivitypatternofbrainw__es.Youreyeswillbegintodartaroundunderyourclosedeyelidsasifyouwerelookingatsomethingoccurringinfrontofyou.Thisperiodofrapideyemovementlastsforsome8to15minutesandiscalledREMsleep.ItisduringREMsleepperiodyourbodywillsoonrelaxagainyourbreathingwillslipgentlybackfromstage1tostage4sleep----onlytoriseon__againtothesu_____ofnearconsciousnesssome80minuteslater.
50.__llsandTemperature__llscannotre__inaliveoutside__rtainlimitsoftemperatureandmuchnarrowerlimits__rktheboundariesofeffectivefunctioning.Enzymesystemsof__m__lsandbirdsaremostefficientonlywithinanarrowrangearound37C;adepartureofafewdegreesfromthisvalueseriouslyimpairstheirfunctioning.Eventhough__llscansurvivewiderfluctuationstheintegratedactionsofbodilysystemsareimpaired.Otherani__lsh__eawidertoleran__forchangesofbodilytemperature.For__nturiesithasbeenrecognizedthat__m__lsandbirdsdifferfromotherani__lsinthewaytheyregulatebodytemperature.Waysofcharacterizingthedifferen__h__ebecomemoreaccurateandmeaningfulovertimebutpopularterminologystillreflectstheolddivisioninto“warm-blooded”and“cold-blooded”species;warm-bloodedincluded__m__lsandbirdswhereasallothercreatureswereconsideredcold-blooded.Asmorespecieswerestu___ditbecameevidentthatthisclassificationwasinadequate.Afen__lizardoradesertiguana-eachcold-blooded----usuallyhasabodytemperatureonlyadegreeortwobelowthatofhu__nsandsoisnotcold.Thereforethenextdistinctionwas__debetweenani__lsthat__intainaconstantbodytemperaturecalledhome0thermsandthosewhosebodytemperaturevarieswiththeirenviro__entscalledpoikilotherms.Butthisclassificationalsoprovedinadequatebecauseamong__m__lsthereare__nythatvarytheirbodytemperaturesduringhibernation.Furthermore__nyinvertebratesthatliveinthedepthsoftheo__anneverexperien__changeinthedepthsoftheo__anneverexperien__changeinthechillofthedeepwaterandtheirbodytemperaturesre__inconstant.投顶网___.touding.com像玩游戏一样开心学习、开心背单词,一起PK吧。