生物专业英语翻译+蒋悟生+第

PAGE/NUMPAGESLessonOne（4学时）InsidetheLivingCell:StructureandFunctionofInternalCellParts1.Cytoplasm:TheDynamic,MobileFactory细胞质：动力工厂Mostofthepropertiesweassociatewithlifearepropertiesofthecytoplasm.Muchofthemassofacellconsistsofthissemifluidsubstance,whichisboundedontheoutsidebytheplasmamembrane.Organellesaresuspendedwithinit,supportedbythefilamentousnetworkofthecytoskeleton.Dissolvedinthecytoplasmicfluidarenutrients,ions,solubleproteins,andothermaterialsneededforcellfunctioning.生命的大部分特征表现在细胞质的特征上。细胞质大部分由半流体物质组成，并由细胞膜（原生质膜）包被。细胞器悬浮在其中，并由丝状的细胞骨架支撑。细胞质中溶解了大量的营养物质，离子，可溶蛋白以及维持细胞生理需求的其它物质。2．TheNucleus:InformationCentral（细胞核：信息中心）Theeukaryoticcellnucleusisthelargestorganelleandhousesthegeneticmaterial(DNA)onchromosomes.(Inprokaryotesthehereditarymaterialisfoundinthenucleoid.)Thenucleusalsocontainsoneortwoorganelles-thenucleoli-thatplayaroleincelldivision.Apore-perforatedsaccalledthenuclearenvelopeseparatesthenucleusanditscontentsfromthecytoplasm.Smallmoleculescanpassthroughthenuclearenvelope,butlargermoleculessuchasmRNAandribosomesmustenterandexitviathepores.真核细胞的细胞核是最大的细胞器，细胞核对染色体组有保护作用（原核细胞的遗传物质存在于拟核中）。细胞核含有一或二个核仁，核仁促进细胞分裂。核膜贯穿许多小孔，小分子可以自由通过核膜，而象mRNA和核糖体等大分子必须通过核孔运输。3.Organelles:SpecializedWorkUnits（细胞器：特殊的功能单位）Alleukaryoticcellscontainmostofthevariouskindsoforganelles,andeachorganelleperformsaspecializedfunctioninthecell.Organellesdescribedinthissectionincluderibosomes,theendoplasmicreticulum,theGolgicomplex,vacuoles,lysosomes,mitochondria,andtheplastidsofplantcells.所有的真核细胞都含有多种细胞器，每个细胞器都有其特定功能。本节主要介绍核糖体，内质网，高尔基体系，液泡，溶酶体，线粒体和植物细胞中的质体。Thenumberofribosomeswithinacellmayrangefromafewhundredtomanythousands.Thisquantityreflectsthefactthat,ribosomesarethesitesatwhichaminoacidsareassembledintoproteinsforexportorforuseincellprocesses.Acompleteribosomeiscomposedofonelargerandonesmallersubunit.DuringproteinsynthesisthetwosubunitsmovealongastrandofmRNA,"reading"thegeneticsequencecodedinitandtranslatingthatsequenceintoprotein.SeveralribosomesmaybecomeattachedtoasinglemRNAstrand;suchacombinationiscalledapolysome.Mostcellularproteinsaremanufacturedonribosomesinthecytoplasm.Exportableproteinsandmembraneproteinsareusuallymadeinassociationwiththeendoplasmicreticulum.核糖体的数量变化从几百到几千，核糖体是氨基酸组装成蛋白质的重要场所。完整的核糖体由大亚基和小亚基组成。核糖体沿着mRNA移动并阅读遗传密码，翻译成蛋白质。一条mRNA上可能有多个核糖体，称多聚核糖体。大多数细胞蛋白是由细胞质中核糖体生产。输出蛋白和膜蛋白通常与内质网有关。Theendoplasmicreticulum,alacyarrayofmembranoussacs,tubules,andvesicles,maybeeitherrough(RER)orsmooth(SER).Bothtypesplayrolesinthesynthesisandtransportofproteins.TheRER,whichisstuddedwithpolysomes,alsoseemstobethesourceofthenuclearenvelopeafteracelldivides.内质网，带有花边的生物囊，有管状，泡状之分，以及光滑和粗糙面区别。两种都与蛋白质的合成和运输有关。粗糙内质网上分布许多核糖体，也可能提供细胞分裂后所需的细胞膜。SERlackspolysomes;itisactiveinthesynthesisoffatsandsteroidsandintheoxidationoftoxicsubstancesinthecell.Bothtypesofendoplasmicreticulumserveascompartmentswithinthecellwherespecificproductscanbeisolatedandsubsequentlyshuntedtoparticularareasinoroutsidethecell.光滑内质网上无核糖体，主要作用是脂肪和类固醇的合成以及细胞内有毒物质的氧化。两种内质网合成的产物在其中进行分流或运输到细胞外。Transportvesiclesmaycarryexportablemoleculesfromtheendoplasmicreticulumtoanothermembranousorganelle,theGolgicomplex.WithintheGolgicomplexmoleculesaremodifiedandpackagedforexportoutofthecellorfordeliveryelsewhereinthecytoplasm.运输小泡能够将可运输分子从内质网运输到高尔基复合体上。在高尔基复合体中修饰，包装后输出细胞或传递到细胞质中的其他场所。Vacuolesincellsappeartobehollowsacsbutareactuallyfilledwithfluidandsolublemolecules.Themostprominentvacuolesappearinplantcellsandserveaswaterreservoirsandstoragesitesforsugarsandothermolecules.Vacuolesinanimalcellscarryoutphagocytosis(theintakeofparticulatematter)andpinocytosis(vacuolardrinking).细胞中的液泡好象是中空的，但实际上充满了液体和可溶分子。最典型的液泡存在于植物细胞中，储备水，糖以及其它分子。动物中的液泡起吞噬和胞饮作用。Asubsetofvacuolesaretheorganellesknownaslysosomes,whichcontaindigestiveenzymes(packagedinlysosomesintheGolgicomplex)thatcanbreakdownmostbiologicalmacromolecules.Theyacttodigestfoodparticlesandtodegradedamagedcellparts.溶酶体是液泡亚单位，含有消化酶，降解大部分生物大分子。消化食物微粒和降解损伤的细胞残片。Mitochondriaarethesitesofenergy-yieldingchemicalreactionsinallcells.Inaddition,plantcellscontainplastidsthatutilizelightenergytomanufacturecarbohydratesintheprocessofphotosynthesis.ItisonthelargesurfaceareaprovidedbytheinnercristaeofmitochondriathatATP-generatingenzymesarelocated.Mitochondriaareself-replicating,andprobablytheyaretheevolutionarydescendantsofwhatwereoncefree-livingprokaryotes.线粒体是细胞中化学产能的场所。另外，植物细胞中的质体在光合作用中利用光能产生碳水化合物，线粒体内嵴上提供了很大的表面积并分布着产ATP酶。线粒体自我复制，并且可能是自由生活的原核生物在进化中形成的后代。Therearetwotypesofplastids:leucoplasts,whichlackpigmentsandserveasstoragesitesforstarch,proteins,andoils;andchromoplasts,whichcontainpigments.Themostimportantchromoplastsarechloroplasts-organellesthatcontainthechlorophyllusedinphotosynthesis.Theinternalstructureofchloroplastsincludesstacksofmembranescalledgrana,whichareembeddedinamatrixcalledthestroma.质体有两种类型：白色体，缺乏色素，是淀粉，蛋白质和油的储备场所；色质体，含有色素。叶绿体是最重要的色质体，含有与光合作用有关的叶绿素。叶绿体的内部结构是由多层膜形成的叶绿体基粒，其中包埋在基质中的基粒称子座。4.TheCytoskeleton（细胞骨架）Alleukaryoticcellshaveacytoskeleton,whichisaconvolutedlatticeworkoffilamentsandtubulesthatappearstofillallavailablespaceinthecellandprovidessupportforvariousotherorganelles.Alargeportionofthecytoskeletonconsistsofthreadlikemicrofilamentscomposedmainlyofthecontractileproteinactin.Theyareinvolvedinmanytypesofintracellularmovementsinplantandanimalcells.Asecondprotein,myosin,isinvolveinthecontractionofmusclecells.Anothermainstructuralcomponentofthecytoskeletonconsistsofmicrotubules,whicharecomposedoftheglobularproteintubulinandtogetheractasscaffoldingthatprovidesastablecellshape.Cytoskeletalintermediatefilamentsappeartoimparttensilestrengthtothecellcytoplasm.Mechanoenzymessuchasmyosin,dynein,andkinesininteractwiththecytoskeletalfilamentsandtubulestogenerateforcesthatcausemovements.所有的细胞都有细胞骨架，网络结构的纤丝充满了它所能触及的全部空间并且对细胞器提供支持作用。细胞骨架大部分由微丝组成，微丝主要由可收缩的肌动蛋白组成。动植物细胞的许多种类型细胞内运动与肌动蛋白有关。第二类蛋白是肌球蛋白，它与肌肉细胞的收缩有关。细胞骨架的另一个主要结构成分是微管，由球状的微管蛋白组成，象脚手架一般维持细胞的稳定形态。细胞骨架的中间丝提供了细胞质伸缩动力。机械酶，例如，肌球蛋白，动力蛋白，驱动蛋白与微丝，微管相互作用产生动力而引起细胞运动。5.CellularMovements（细胞运动Althoughthecytoskeletonprovidessomestability稳固tocells,itsmicrotubules英[ˌmaikrəuˈtju:bju:l]andfilaments丝状物andtheirassociatedproteinsenablecellstomovebycreeping爬行orgliding滑动.Suchmovementsrequireasolid固体的substratetowhichthecellcanadhere附着andcanbeguidedbythegeometrydʒiˈɔmitri] 几何形状ofthesurface.Somecellsalsoexhibit[iɡˈzibit]展览chemotaxis,keməˈtæksis趋药性theabilitytomovetowardorawayfromthesourceofadiffusing扩散chemical.尽管细胞骨架提供了细胞的某些稳定性，微丝，微管及相关蛋白能使细胞爬行或滑动。这种运动需要固体基质依托并通过表面几何形状的改变而运动。某些细胞具备趋药性，即趋向或逃离扩散开的化学源。Certaineukaryoticcellscanswimfreelyinliquidenvironments,propelledbywhiplikecilia[ˈsiliə]纤毛orflagella英[fləˈdʒelə鞭毛.Bothciliaandflagellahavethesameinternalstructure:ninedoublets(pairsofmicrotubules)arearrangedinaringandextendthelengthoftheciliumorflagellum,andtwomoremicrotubulesrundownthecenterofthering.Everyciliumorflagellumgrowsonlyfromthecellsurfacewhereabasalbody基体islocated.Movementisbasedontheactivitiesoftinydynein动力蛋白sidearmsthatextendfromoneofthemicrotubulesofeachdoublet成对的东西.某些真核细胞能在液体液体中自由运动，由纤毛或鞭毛推动。纤毛和鞭毛具有同样的内部结构：九个双微管环形排列，纵向延伸，环中心是两个或以上微管组成。纤毛或鞭毛从细胞表面的基体出生长，双微管的动力蛋白臂从一侧延伸到另一侧而引起运动。Nutrients,proteins,andothermaterialswithinmostplantcellsaremovedaboutviacytoplasmicstreaming.Theprocessoccursasmyosinˈmaiəusin肌凝蛋白proteinsattachedtoorganelles细胞器,小器官pushagainstmicrofilamentsarrayed[əˈrei]展示throughoutthecell.Microfilamentsandmicrotubulesareresponsibleforalmostallmajorcytoplasmicmovements.Duringcelldivision,microtubulesofthespindleassembled集合,收集fromtubutinsubunitsnearorganellescalledcentriolesmovethechromosomes.大部分植物细胞的营养，蛋白质和其它物质由细胞质流运输。这个过程是由于依附在细胞器上的肌球蛋白反推排列在细胞周围的微丝形成的。绝大部分细胞质运动由微丝和微管完成。在细胞分裂期间，中心粒周围的由微管蛋白亚基装配形成的纺锤体微管移向染色体。课后作业：第一第二篇阅读材料 答案 八年级地理上册填图题岩土工程勘察试题省略号的作用及举例应急救援安全知识车间5s试题及答案 ：1B,2C,3B,4B,5D,6c;1A,2B,3D,4ALessonFour（2学时）FoundationsofGeneticsEarlyTheoriesofinheritaneeEarlyideasofinheritanceincludedHippocrates'theoryofpangenesisandAugustWeismandsgermplasmtheory.Basedonexperimentswithmice,Weismannproposedthathereditaryinformationingametestransmittedtraitstoprogeny.Bothoftheseearlyviewsincorporatedtheblendingtheory:theyheldthatheritabletraitsofthetwoparentsblend,sothatthedistinctcharacteristicsofeacharelostinoffspring.遗传学的早期理论包括泛生说和种质理论。基于小鼠实验，维丝曼提出遗传信息储存在配子中并将遗传信息传递给后代。这两个早期观点合起来形成融合理论：子代拥有父母本混合的遗传特征，而不完全象亲代。GregorMendelandtheBirthofGeneticsGregorMendel,anAugustinianmonkinthemonasteryatBrunn,Austria,isknownasthe"fatherofgenetics."Havingbeenexposedtotheoriesoftheparticulatenatureofmatterwhileauniversitystudentandhavingabackgroundinmathematics,Mendelcarriedoutaseriesofcarefullyplannedexperimentsthatdemonstratedtheparticulatenatureofheredity.HisrevolutionaryideaswereneitherunderstoodnoraccepteduntilmanyyearsafterMendeldied.孟德尔，众所周知的遗传学之父，是一名修道士。当他还是大学生时就提出了物质的粒子属性。孟德尔进行了一系列周密安排的实验来证实遗传的颗粒性。直到他去世后，他的理论才被理解和接受。Mendel'sClassicExperimentsMendelstudiedgeneticsthroughplant-breedingexperimentswiththegardenpea,aplantspeciesthatisself-fertilizingandbreedstrue(eachoffspringisidenticaltotheparentinthetraitofinterest).Totesttheblendingtheory,hefocusedhisresearchonsevendistinctcharacters.Eachofthesecharacters,suchasseedcolorandplantheight,presentonlytwo,clear-cutpossibilities.Healsorecordedthetypeandnumberofallprogenyproducedfromeachpairofparentpeaplants,andfollowedtheresultsofeachcrossfortwogenerations.孟德尔通过豌豆实验研究遗传学，豌豆是自花授粉植物和纯品系。为验证融合理论，他的研究主要集中在7个特征上。例如，种子颜色，植株高度，这些特征只有两个明确的可能性。他 记录 混凝土 养护记录下载土方回填监理旁站记录免费下载集备记录下载集备记录下载集备记录下载 了产生的每一个子代类型和数量，在杂交产生子2代。Foreachofthecharactershestudied,Mendelfoundthatonetraitwasdominantwhiletheotherwasrecessive.Inthesecondfilial(F2)generation,theratioofdominanttorecessivewas3:1.Mendeldeducedthatthisresultwaspossibleonlyifeachindividualpossessesonlytwohereditaryunits,onefromeachparent.TheunitsMendelhypothesizedaretodayknownasalleles,alternativeformsofgenes.Genesarethebasicunitsofheredity.Anorganismthatinheritsidenticalallelesforatraitfromeachparentissaidtobehomozygousforthattrait;ifdifferentallelesforatraitareinherited,theorganismisheterozygousforthattrait.Whenanorganismisheterozygousforatrait,theresultingphenotypeforthattraitexpressesonlythedominantallele.Thus,theorganism’sphenotype—itsphysicalappearanceandproperties-differsfromitsgenotype,whichmayincludebothadominantandarecessiveallele.ApictorialrepresentationofallpossiblecombinationsofageneticcrossisknownasaPunnettsquare.对于每个特征而言，要么显形，要么隐性。在子2代中显形与隐性比为3∶1。只有在每个个体仅拥有两个研究遗传单元，并每个单元来自一个亲代时，实验结果才成立。此遗传单元就是今天共识的等位基因。两个一样的等位基因决定一个特征，称纯合。相反，称杂合。当生物是杂合时，它的表型由显性基因决定。因此，生物的表型与基因型是不同的。旁纳特方格可以陈列所有可能的遗传组合。TheresultsofMendel'sexperimentsondominantandrecessiveinheritancelettoMendel'sfirstlaw:thelawofsegregation.Thislawstatesthatforagiventraitanorganisminheritsoneallelefromeachparent.Togethertheseallelesformtheallelepair.Whengametesareformedduringmeiosis,thetwoallelesbecomeseparated(halvingofchromosomenumber).TogainevidenceforhistheoryMendelperformedtestcrosses,matingplantsofunknowngenotypetoplantsthatwerehomozygousrecessiveforthetraitofinterest.Theratioofdominantphenotypes(ifany)intheprogenymakesclearwhethertheunknowngenotypeisheterozygous,homozygousdominant,orhomozygousrecessive.分离定律，生物只遗传父母本等位基因对的一个等位基因。减数分裂期形成配子时两个等位基因分离。为验证此理论，他做了测交实验，即基因型未知的植物与纯合的隐性基因植物杂交。子代显性表型可以明确测得杂合基因或纯合基因的基因型。Mendel'sIdeasandtheLawofindependentAssortmentMendelalsoperformeddihybridcrosses,whichenabledhimtoconsiderhowtwotraitsareinheritedrelativetooneanother.Thisworklettothelawofindependentassortment,whichstatesthattheallelesofgenesgoverningdifferentcharactersareinheritedindependently.AnapparentexceptiontoMendel'slawsisincompletedominance,aphenomenoninwhichoffspringofacrossexhibitaphenotypethatisintermediatebetweenthoseoftheparents.However,incompletedominancereflectsthefactthatbothallelesforthetraitinquestionexertaneffectonthephenotype.Theallelesthemselvesremainseparate.双因子杂合试验，两个特征是如何相互影响遗传的。试验结果产生独自分配定律，即等位基因独立遗传。特例是，不完全显性。子代的表型是父母本的中间类型。不完全显性说明了两个等位基因对表型都有影响。，等位基因会继续分离。Mendelpresentedhisideasin1866inascientificpaperpublishedbytheBrunnSocietyforNaturalHistory.Unfortunately,themeaningofhisresearchwasnotunderstoodbyotherscientistsoftheday.Hisworkwasrediscoveredin1900byCarlCorrensandHugodeVries.1866年，孟德尔在自然史上发表了他的科学论文，陈诉了他的观点。不幸的是，他的研究不被当时科学家接受。在1900年，他的著作再被发现利用。ChromosomesandMendelianGeneticsSoonafterMendel'sworkwasrediscovered,WalterSuttonandTheodorBoveriindependentlyproposedthatthehereditaryunitsmightbelocatedonchromosomes.ExperimentstoprovethishypothesiswerecarriedoutbyThomasHuntMorganandhisstudentsatColumbiaUniversity,inresearchonthesexchromosomesoffruitflies.Morgan'sstudieswerealsothefirstexplorationofsex-linkedtraits.Italsoledtothediscoveryin1916byCalvinBridgesofthephenomenonofnondisjunction,inwhichachromosomepairfailstosegregateduringmeiosis.孟德尔著作被再发现不久，WalterSutton和TheodorBoveri提出，遗传单位可能定位在染色体组上。伴性遗传又导致了不分离现象的发现，即在减数分裂中，染色体对不分离。课后作业：第一篇阅读材料答案：1C,2C,3A,4A,5B,6BLessonSix（2学时）TheOriginandDiversityofLifeAHomeforLife:FormationoftheSolarSystemandPlanetEarthThestoryoflife'soriginsbeginswiththeformationoftheearth.Thesequenceofeventsthatgaverisetoourplanetbegan,inturn,withthecosmicexplosionphysicistscalltheBigBang.Thesunatthecenterofoursolarsystemcondensedfromacloudofprimordialmatterroughly5billionyearsago;theplanets,includingtheearth,condensedabout4.6billionyearsago.Theearthiscomposedofanumberoflayers:asolidcrust,asemisolidmantle,andalargelymolten(liquid)corethathasasolidcenter.BasicphysicalfeaturesofEarththatmayhavemadetheemergenceoflifepossibleincludetheplanet'ssize,temperature,composition,anddistancefromthesun.Themajorcurrenthypothesisholdsthatlifearosespontaneouslyontheearlyearthbymeansofchemicalevolutionfromnonlivingsubstances.生命起源于地球的形成。大爆炸是我们行星形成的开始。太阳在50亿年前生成，位于太阳系中心，行星，包括地球，在46亿年前生成。地球由多层组成：坚硬的地壳，半流体的地幔，一个很大的溶解中心中存在一个坚实的中心。地球的基本特征使生命起源成为可能，包括行星的大小，温度，组成以及离太阳的距离。当前主要假设认为，由非生命的化学物质进化过程自发产生了生命。TheEmergenceoflife:OrganicandBiologicalMoleculesonaPrimitivePlanetEvidenceforprelifestagesofchemicalorganizationcomesfromlaboratoryexperimentsthattrytoduplicatethephysicalenvironmentandchemicalresourcesoftheearlyearth.Theseexperiments,includingthepioneeringworkofMillerandUrey,havesuccessfullyproducedorganicmonomersincludingaminoacids,simplesugars,andnucleicacidbases.Theprobablenextsteptowardlifewasthespontaneouslinkingofsuchmonomersintopolymerssuchasproteinoidsandnucleiacids.Currentresearchsuggeststhatlikelysitesforthispolymerizationwereclayorrocksurfaces.通过创造出地球早期的自然条件和化学资源条件，科学家在实验室中已经获得了化学有机体生命前阶段的证据。这些实验包括米勒等早期所做工作，成功地产出了有机单体，包括氨基酸，单糖，核酸碱基。这些单体自发的连接成多聚体，如类蛋白和核酸，使进入生命状态成为可能。这些聚合作用可能发生在泥土或岩石表面。Researchershavefoundthat,whenenergyisavailabletoasystem,theycangeneratethreekindsoforganicmolecularaggregates.TheRussianAleksandrOparinobtainedpolymer-richdroplets,calledcoacervatesfromsolutionsofpolymers.SidneyFoxgeneratedproteinoidmicrospheresfrommixturesofaminoacidsandwater.Athirdlaboratorystructureistheliposome,asphericallipidbilayerthatformsfromphospholipids.Astructuresimilartooneormoreoftheseaggregatesmayhavebeentheprecursoroftruecells.当一个系统获得能量时，可能发生3种有机分子的聚集。从多聚物的溶液中俄国科学家获得了富含小液滴的多聚物，即凝聚物。从氨基酸和水的混合液中Fox获得了类蛋白微球体。实验室第三个结构物质是脂质体，即由磷脂形成的球形脂双层结构。FurtherstepsintheappearanceofcellsontheearthincludedthedevelopmentofRNAandDNAasbiologicalinformationmolecules.EvidencesuggeststhatRNA,whichcanformspontaneouslyunderconditionsmimickingthoseoftheearlyearth,wasthefirstinformationalmolecule.ThediscoveryofRNAribozymes-RNAthatcanactasanenzymelikecatalystsuggeststhatsuchcatalyticRNAalsocouldhaveassemblednewRNAsfromearlynucleotides.CertaincatalyticRNAscanalsocarryoutsexlikeexchangesofpiecesofRNA.RNA可能是地球早期形成的第一个贮藏信息的物质。在实验室模拟早期地球自然条件下其可自发形成。核酶的发现说明它可以催化早期核酸形成新的RNA。对于RNA物种而言，某些催化RNA具备类似于性交换的功能。Followingthedevelopmentofalipid-proteinsurfacelayerandreplicatingRNAandDNAinformationalmolecules,theeventsleadingtotheemergenceoflivingcellswouldhaveincludedtheoriginofthegeneticcode;thesequesteringofRNAorDNAintocell-likestructures;andthedevelopmentofmetabolicpathways.接下来脂蛋白表层的形成，RNA的复制,DNA信息分子的形成，最终导致活细胞的出现，包括最初的遗传密码，RNA或DNA被包裹进细胞样的结构中；及代谢途径的建立。TheEarliestCellsTheoldestfossilsthatmayrepresentlivingcellsarefoundinrocksthatareabout3.5billionyearsold.Thecellswereprobablyanaerobicheterotrophs,withautotrophsarisingmuchlater.ThefirstautotrophsproducedtheirownnutrientsandreleasedO,-ametabolicby-productthathadacrucialimpactonlaterlifeforms.Theresultingozonelayerintheearth'satmospherereducedthepenetrationofultravioletlight.Asaresult,cellswouldsurviveinshallowwaterandonthelandsurface.Theincreasingquantityofatmosphericoxygenalsopermittedtheevolutionofaerobiccellsandcellularrespiration,whichinturnsignaledthebeginningoftheglobalcarboncycle.Althoughtheearliestcellswereallprokaryotes,byabout1.5billionyearsagoeukaryotesappeared.能说明活细胞存在的最古老化石大约有35亿年了。最早出现的细胞可能是厌氧异氧生物，自养生物很久后出现。最早的自养生物自己生产营养并释放氧气，这个新陈代谢副产品对后期生命的形成有一个深远的影响。臭氧层的出现减少了紫外线的渗透。结果，细胞就能够在浅水区和陆地上生存了。大气中氧气数量的增加使得需氧细胞进化并产生细胞呼吸，这预示着全球碳循环的开始。最早期的细胞都是原核生物，直到15亿年后，真核细胞才出现。TheChangingFaceofplanetEarthChangesinlandmasses,theseas,andclimatehavegreatlyaffectedtheevolutionoflifeontheearth.Thebasicpartsoftheplanetincludealight,solidcrustoverahot,semisolidmantleandaninner,partiallymoltencore.Massivesegmentsorplatesofthecrustmoveoverthemantleintheprocessofcontinentaldrift.Overthepast500millionyears,continentaldrifthassculptedtheearth'scruststoproducetheformanddistributionofpresent-daycontinents.Climaticchangesthatgreatlyaffectedlivingorganismsaccompaniedtheseplatemovements;theperiodwasmarkedbyoccasionalwavesofmassextinctionsoflivingcreatures.Organismswerealsoaffectedbyperiodsofglaciationthatfollowedvariationsintheearth'sorbitandintheoutputofenergybythesun.大陆板快，海洋的改变，以及气候对地球生命的进化都有深远影响。地幔上大板快地壳的挤压形成大陆漂移。大陆漂移雕塑了地壳的外观，使现在大陆形成。伴随板块运动，气候改变对活有机体有深远影响。在特定时期的生物大量灭亡高峰是这个时期的见证。生物也受冰河期影响，在冰河期，地球轨道和太阳能的输出都发生了很大变化。Taxonomy:CategorizingtheVarietyoflivingThingsBiologistsusethebinomialsystemofnomenclaturedevelopedbyLinnaeustocategorizethevarietiesoflifeontheearth.Thesystemassignseachtypeoforganismtoagenusandspecies.Organismsarethenfurtherclassifiedintohighertaxonomiccategories-family,order,class,division(plants),phylum(animals),andkingdom.Evidencefrommanysubfieldsofbiology,suchasbiochemistryandcomparativeanatomy,helpsdefinespeciesandhighertaxa(taxon).Andwhereasspecieswereoriginallydefinedintermsofmorphologicaltraits,todaybiologistsgenerallyusethecriterionofareproductivelyisolatedpopulation.生物学家利用林奈发展的双名法对生物分类。系统选定每个类型的生物进入属和种，然后将生物进一步分类更高级类别中，即科，目，纲，门，界。来自于生物化学和比较解剖学等亚生物学领域的证据有助于划分物种和更高级的分类单位，然而物种最初依据形态学特征进行分类的，今天生物学家大体上使用孤立多产的群体作为 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 。Taxonomyrevealsagreatdealabouttheevolutionaryrelationshipsamongorganisms.Acladeisataxonomicunitwhosemembersarederivedfromacommonancestor.分类学揭示了物种间进化的大量关系。进化枝中的成员来自一个共同的祖先。TheFiveKingdomsAphylogenetictreeisagraphicrepresentationofevolutionaryrelationships.Yourtextusesacommonfive-kingdomarrangement:organismsaregroupedintothekingdomsMonera,Protista,Fungi,Plantae,andAnimalia.Althoughthissystemisaconvenientorganizationaltool,thekingdomsareprobablynotrueclades.进化系统树是进化关系的图解表现。教材中使用一个通用的5界：？，？，真菌，植物，动物。尽管这个系统是一个便利的组织工具，5界划分可能不是正确的进化枝。课后作业：第一篇阅读材料答案：1B,2A,3B,4C,5A,6CLessonNineTheOriginofSpeciesHowBiologistsDefineaSpeciesModernbiologygenerallydefineaspeciesasgroupofactuallyorpotentiallyinterbreedingpopulationsthatisreproductivelyisolatedfromthesuchgroups.Membersofaspeciescaninterbreedwitheachother,buttheycannotbreedwithorganismsbelongingtoanotherspecies.Oneadvantageofthestandardofreproductiveisolationisthatitisveryprecise.Notice,however,thatitcanonlybeappliedtoorganismsthatreproducesexually.Asexualreproducers,includingmostprokaryotes,manyplants,andsomeanimals,mustbeclassifiedintospeciesonthebasisofphysical(biochemicalormorphological)traits.现代生物学大体将物种定义为实际上的一群或潜在的杂交群体，即从这个群体隔离繁殖的后代。种族中个体可以互相交配，但种间不能。这种繁殖隔离的一个优势是很精确。但仅适用于性繁殖的生物。非性繁殖，包括大多数原核生物，许多植物，某些动物，需要通过自然特征进行归类。PreventingGeneExchangeTwogeneraltypesofmechanismsoperatetoblocktheexchangeofgenesbetweenindividualsofrelatedgroups.Thefirstgeneraltypeismadeupofprezygoticisolatingmechanismsthatpreventtheformationofzygotes.Prezygoticisolationfallsintotwocategories:ecologicalandbehavioral.Inthefirstcase,tworelatedgroupmaybecomeadaptedtoslightlydifferentenvironments-perhapsvaryingsoiltypesorfoodsources.Overtime,thesegeneticdifferencesbecomesogreatthatsuccessfulcross-fertilizationcannolongertakeplace.Inbehavioralisolation,relatedgroupsevolvedifferingbehaviorssuchasspecificmatingrituals-thatrestricttheexchangeofgenestomembersofthesamegroup.两种基因