鲨鱼-软骨鱼类.ppt

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1、ElasmobranchBiologyElasmobranch:AnyofnumerousfishesoftheclassChondrichthyes,characterizedbyacartilaginousskeletonandplacoidscalesandincludingthesharks,rays,andskates.FLORIDAPROGRAMFORSHARKRESEARCHFloridaMuseumofNaturalHistory鲨鱼-软骨鱼类生物TopicsBasicMorphologySenses

2、DigestionsystemCirculatorysystemOsmoregulationReproductionsystemEvolutionaryadaptationsThereareapproximately400describedspeciesofsharks.Additionally,therearearound400speciesofbatoids(raysandskates).Whendidsharksfirstappear?Sharksandtheirancestorsfirstappearedin

3、thelateSilurian/earlyDevonian,oraround400millionyearsago.Sharkspredatedinosaursby200millionyears.BodyPlanStingraysvs.SkatesWhat’sthedifference?StingrayFinsSkateFinsPectoralPelvicPectoralPelvicDorsalCaudalSpiracleSpiracleStingrayvs.SkateMosthavevenomousspineNosp

4、inepresentStingrayTailSpineDorsalfin-foldAnalfin-foldReproduction:Aplacentalviviparity(livebirth).Reproduction:Oviparous(layeggs).Stingrayvs.SkateCanbeverylargeinsize.Usuallysmallerinsize.Stingrayvs.SkateStingrayvs.SkateIngeneralhavethinnertailsCanhaveverythick

5、tailsElasmobranchSensesElasmobranchSensesOlfactory(Smell):HighlyacutesenseofsmellUsedtolocatefoodorpotentialmatesPairedopeningswithorwithoutaconnectiontothemouthNotusedforrespirationLackexternalearsGoodsenseofhearingespeciallyinthelowerfrequencyrangeOftenfirsts

6、ensetodetectpreyfromadistanceElasmobranchSensesSound:ElasmobranchSensesPressure:Sharks,likeotherfish,havealaterallinesystemthatcandetectpressurewavesinthewater.SensestrugglingpreySharkeyesightwillvarybyspeciesbutmosthavegoodvisualacuitySharkshavebothrods(light/

7、dark)andcones(color)Retinapossesa“tapetumlucidum”ElasmobranchSensesVision:ElasmobranchSensesElectric:Electrosensorysystem:“AmpullaeofLorenzini”AllowsfordetectionofweakelectricfieldsgivenoffbypreyorganismsorpotentialmatesDigestionSharkDigestionLargeLiverupto25%o

8、fbodyweight.ShortGutlongpassagerateSpiralValveintestineincreasesurfaceareaCirculatorySystemFourchamberheart:sinusvenosus,atrium,ventricle,andconusarteriosus.Onedirectionoffl