ElasmobranchBiologyElasmobranchBiologyElasmobranch:AnyofnumerousfishesoftheclassElasmobranch:AnyofnumerousfishesoftheclassChondrichthyes,characterizedbyacartilaginousskeletonandChondrichthyes,characterizedbyacartilaginousskeletonandplacoidscalesandincludingthesharks,rays,andskates.placoidscalesandincludingthesharks,rays,andskates.FLORIDAPROGRAMFORSHARKRESEARCHFloridaMuseumofNaturalHistory鲨鱼-软骨鱼类生物TopicsTopics•BasicMorphologyBasicMorphology•SensesSenses•DigestionsystemDigestionsystem•CirculatorysystemCirculatorysystem•OsmoregulationOsmoregulation•ReproductionsystemReproductionsystem•EvolutionaryadaptationsEvolutionaryadaptations•Thereareapproximately400describedspeciesofsharks.Thereareapproximately400describedspeciesofsharks.•Additionally,therearearound400speciesofbatoidsAdditionally,therearearound400speciesofbatoids(raysandskates).(raysandskates).Whendidsharksfirstappear?Whendidsharksfirstappear?•SharksandtheirancestorsfirstappearedinthelateSharksandtheirancestorsfirstappearedinthelateSilurian/earlyDevonian,oraround400millionyearsago.Silurian/earlyDevonian,oraround400millionyearsago.•Sharkspredatedinosaursby200millionyears.Sharkspredatedinosaursby200millionyears.BodyPlanBodyPlanElasmobranchSensesElasmobranchSensesElasmobranchSensesElasmobranchSensesOlfactory(Smell):Olfactory(Smell):•HighlyacutesenseofsmellHighlyacutesenseofsmell•UsedtolocatefoodorpotentialmatesUsedtolocatefoodorpotentialmates•PairedopeningswithorwithoutaPairedopeningswithorwithoutaconnectiontothemouthconnectiontothemouth•NotusedforrespirationNotusedforrespiration•LackexternalearsLackexternalears•GoodsenseofhearingespeciallyintheGoodsenseofhearingespeciallyinthelowerfrequencyrangelowerfrequencyrange•OftenfirstsensetodetectpreyfromOftenfirstsensetodetectpreyfromadistanceadistanceElasmobranchSensesElasmobranchSensesSound:Sound:ElasmobranchSensesElasmobranchSensesPressure:Pressure:•Sharks,likeotherfish,Sharks,likeotherfish,havealaterallinesystemhavealaterallinesystemthatcandetectpressurethatcandetectpressurewavesinthewater.wavesinthewater.•SensestrugglingpreySensestrugglingprey•SharkeyesightwillvarybyspeciesbutSharkeyesightwillvarybyspeciesbutmosthavegoodvisualacuitymosthavegoodvisualacuity•Sharkshavebothrods(light/dark)andSharkshavebothrods(light/dark)andcones(color)cones(color)•Retinapossesa“tapetumlucidum”Retinapossesa“tapetumlucidum”ElasmobranchSensesElasmobranchSensesVision:Vision:ElasmobranchSensesElasmobranchSensesElectric:Electric:•Electrosensorysystem:“AmpullaeofLorenzini”Electrosensorysystem:“AmpullaeofLorenzini”•AllowsfordetectionofweakelectricfieldsgivenoffbyAllowsfordetectionofweakelectricfieldsgivenoffbypreyorganismsorpotentialmatespreyorganismsorpotentialmatesDigestionDigestionSharkDigestionSharkDigestion•LargeLiverLargeLiver–upto25%ofbodyweight.upto25%ofbodyweight.•ShortGutShortGut–longpassageratelongpassagerate•SpiralValveintestineSpiralValveintestine–increasesurfaceareaincreasesurfaceareaCirculatorySystemCirculatorySystem•Fourchamberheart:Fourchamberheart:sinusvenosus,atrium,ventricle,andsinusvenosus,atrium,ventricle,andconusarteriosus.conusarteriosus.•Onedirectionofflow:HeartOnedirectionofflow:HeartGillsGillsBodyBody•Ectotherms/EndothermsEctotherms/EndothermsOsmoregulationOsmoregulation•SharksareslightlyhyperosmotictoseawaterSharksareslig...
