英语英文版动物世界动物介绍introductiontoanimals

IntroductiontoAnimals,Characteristics,MulticellularOrganizationHeterotrophicSexualreproductionanddevelopmentMovement,AnimalClasses,Ananimalclassismadeupofanimalsthatareallalikeinimportantways.Scientistshavegroupedanimalsintoclassestomakeiteasiertostudythem.Therearemanydifferentanimalclassesandeveryanimalintheworldbelongstooneofthem.Thefivemostwellknownclassesofvertebrates(animalswithbackbones)aremammals,birds,fish,reptiles,amphibians.Theyareallpartofthephylumchordata-Irememberchordotabythinkingofspinalchord.Therearealsoalotofanimalswithoutbackbones.Thesearecalledinvertebratesandarepartofthephylumarthropoda(arthropods).Twoofthemostcommonlyknownclassesinthisphylumarearachnids(spiders)andinsects.www.kidzone.ws/animals/,Mammals,Peoplearemammals.Soaredogs,cats,horses,duckbillplatypuses,kangaroos,dolphinsandwhales.Whatdoalltheseanimalshaveincommon,youask?TheanswerisMILK!Ifananimaldrinksmilkwhenitisababyandhashaironitsbody,itbelongstothemammalclassMammalsareoneofthe6mainclassesofanimals.Animalclassesaregroupsofanimalsthatscientistsconsidertobealikeinsomeimportantways.Mammalsaretheanimalclassthatpeoplebelongto.Thereareonlyabout4,000kindsofmammals.Warm-blooded,Birds,Birdsareanimalsthathavefeathersandthatarebornoutofhard-shelledeggs.Somepeoplethinkthatwhatmakesananimalabirdisitswings.Batshavewings.Flieshavewings.Batsandfliesarenotbirds.Sowhatmakesananimalabird?Theanswerisfeathers!Allbirdshavefeathersandbirdsaretheonlyanimalsthatdo.Thefeathersonabirdswingsandtailoverlap.Becausetheyoverlap,thefeatherscatchandholdtheair.Thishelpsthebirdtofly,steeritselfandland.,Fish,Fisharevertebratesthatliveinwaterandhavegills,scalesandfinsontheirbody.Therearealotofdifferentfishandmanyofthemlookveryoddindeed.Thereareblindfish,fishwithnoseslikeelephants,fishthatshootdownpassingbugswithastreamofwaterandevenfishthatcrawlontolandandhopabout!,Reptiles,Reptilesareaclassofanimalwithscalyskin.Theyarecoldbloodedandarebornonland.Snakes,lizards,crocodiles,alligatorsandturtlesallbelongtothereptileclass.,Amphibians,Amphibiansareborninthewater.Whentheyareborn,theybreathwithgillslikeafish.Butwhentheygrowup,theydeveloplungsandcanliveonland.,Arthropods,Arthropodsisahugephylumofanimals-itincludeselevenanimalclasses:Merostomata,Pycnogonida,Arachnida,Remipedia,Cephalocarida,Branchiopoda,Maxillopoda,Malacostraca,Chilopoda,Diplopoda,andInsecta.Anyanimalsthathavemorethanfour,jointedlegsarearthropods.Insects,spidersandcrustaceansallbelongtothisclassofanimals.,ZoologistArachnologistCarcinologistConchologistEntomologistHerptologistIchthyologistMalacologistMammalogistOrnithologistPaleozoologistMarinebiologistbotanist,MulticellularOrganization,Mostanimalscontainlargenumbersofcells.Humanscontain50trillioncells.Inmostanimals,thereisadivisionoflabor.Specializationistheadaptationofacellforaparticularfunction.Tissuesaretheorganizationofcells.Cellareabletoorganizebythejoiningofcellsbycelljunctions.Cellspecializationhasallowedorganismstoevolveandadapttomanyenvironments.,AnimalsareHeterotrophic,Theymustobtaincomplexorganicmaterialfromothersources.Mostaccomplishthisthroughingestion.Digestionisaccomplishedwithintheanimal.Thisprocessextractsthecarbohydrates,proteinandlipidsfromthefoodeaten.,SexualReproductionandDevelopment,Sexualreproductionrestoresthediploidnumberandincreasesgeneticvariation.Duringthedevelopmentalprocess,thezygoteundergoesmanymitoticdivisions.Theseidenticalcellsmustundergodifferentiation.Differentiationisprocessofcellbecomingdifferentfromeachotherandbeingspecialized.,Movement,Mostanimalareabletomove.Theabilitytomoveresultsfromtheinterrelationsoftwotypesoftissuesfoundonlyinanimals:nervoustissueandmusculartissue.Thereareafewanimalsthataresessile.,OriginandClassification,Thefirstanimalsprobablyarosefromthesea.Taxonomistshavegroupedanimalsintoseveralphylabasedonevolutionaryrelationships.Manytaxonomistrecognize30ormoreanimalphyla.Wewillinvestigate11phyla.TenofthephylaincludeinvertebratesandonlyChordataincludesthevertebrates.,AnimalBodyStructure,SymmetryGermlayersBodyCavities,Symmetry,Asymmetryreferstotheconsistentoverallpatternofstructureofananimal.Animalshavethreepatternsofsymmetry.AsymmetrynosymmetryRadialSymmetrysimilarpartsbranchinalldirectionsfromacentralpointBilateralSymmetry-similarhalvesoneithersideofacentralplane.,PatternsofSymmetry,IdentifytheTypeofSymmetry,Mostanimalshaveadorsal,ventral,anteriorandposteriorsideororientation.DorsaltopVentralbottomAnteriorheadPosterior-tailMostanimalsexhibitcephalization,theconcentrationofsensoryandbrainstructuresintheanterior.Animalswithcephalizationhaveahead!,GermLayers,Germlayersarefundamentaltissuetypesfoundinallanimalsexceptsponges(notruetissues).EctodermMesodermEndoderm,BodyCavities,Mostanimalshaveafluidfilledspacethatformsbetweenthedigestivetractandtheouterwallofthebodyduringdevelopment.ThisspaceisknownasaCOELOM.,Acoelomate(withoutacoelom)2germlayersectodermandendodermnotseparatedbyacavityleastcomplexbodyplanspongesandcnidarians3layeracoelomate3germlayersendoderm,mesodermandectodermnotseparatedbyacavityflatwormsPseudocoelomatepseudocoelomcavityformedbetweenmesodermandendodermroundwormsandrotifersCoelomatecavitydevelopedwithinthemesodermmostcomplexbodyplanmollusks,annelids,arthropods,echinoderms,andchordates,AnimalDiversity,Invertebrates10phyla9