FISHESBio IIRupp

TYPES OF FISHESJawlessCartilaginousBony

FISH CHARACTERISTICS4 hallmarks of chordatesSharksLateral lineAmpullae of LorenziniOperculum

GillsTail typesScale typesFish musculatureSwimming and the swim bladder

TAXONOMYKingdom AnimaliaPhylum ChordataSubphylum Vertebrata

CLASS MYXINIHagfish

CLASS CEPHALOSPIDOMORPHILampreys

CLASS CHONDRICHTHYESSharks, skates, and rays

CLASS ACTINOPTERYGIIRay-finned fishes

CLASS SARCOPTERYGIILobe-finned fishes

CHORDATE HALLMARKSNotochordHagfishes and lampreys keep this their entire livesMade of thick-walled and fluid-filled cells pressed closely together

CHORDATE HALLMARKSDorsal hollow nerve cordNeural tube formationAnterior becomes the brain

CHORDATE HALLMARKSPharyngeal gill slits/pouches

CHORDATE HALLMARKS

FISH DEFINITIONFor our purposes:A gill-breathing, poikilothermic (cold-blooded), aquatic vertebrate that possesses fins and a skin that is usually covered in scalesApproximately 25,000 speciesTwo basic body formsAgnathansjawlessGnathostomesjawed

AGNATHANSCephalospidomorphilampreysectoparasitesMyxinihagfishesscavengers

SUPERCLASS GNATHOSTOMESCartilaginous fishesClass Chondrichthyesapprox. 850 speciesSubclass Elasmobranchiisharks, skates, and raysDogfish anatomy

DOGFISH ANATOMY

DOGFISH ANATOMY

DOGFISH ANATOMY

GNATHOSTOME ADAPTATIONS

GNATHOSTOME ADAPTATIONS

GNATHOSTOME REPRODUCTIVE STRATEGIESInternal fertilizationOviparoussome species lay eggs immediately after fertilizationOvoviviparousretain the developing young in the uterus and they are nourished by yolk sacsViviparousyoung are nourished by a placenta

SUPERCLASS GNATHOSTOMESBony fishes, aka osteichthyesClass Actinopterygiiray-finned fishesClass Sarcopterygiilobe-finned fishes

OSTEICHTHYES ADAPTATIONSOperculumTail typesSkin and scalesMusculatureSwimmingSwim bladderGills

OPERCULUMA bony plate attached to a series of muscles running over the gillsAid in more efficient respirationBernoullis Principle of Fluid Dynamics

TAIL TYPES

SCALE TYPESScales are embedded in the dermis and covered by the epidermisTypesGanoidCycloidCtenoidPlacoid

GANOID SCALES

CTENIOD SCALES

CYCLOID SCALES

PLACOID SCALESTypical in sharks

FISH MUSCULATUREMyomeres-segments of the muscleMyospetadivision point of the myomeresVertical septum and horizontal septum of body cavity

FISH MUSCULATURERed muscle or dark muscle is used in regular swimmingRed muscle is dark due to extra myoglobin and extreme vascularizationRed muscle is often referred to as the bloodlineWhite muscle for escape response

SWIMMINGShort muscular bodies and lunate tails for most efficient swimming

SWIM BLADDERSMaintain neutral buoyancy and depth controlBalloon-like structurePulls gas out of the water to inflateTwo typesAttached to gutancient fishesDetached from gutmore modern fishesFish without swim bladders: tuna, flounder, sharks, deep ocean fishSharks have a huge fatty liver to maintain neutral buoyancy

GILLSMade of filaments called lamellaeRich with blood vesselsCovered by operculum or gill slitsCounter current blood flow of blood and water increases efficiencydemonstration Gill arches are the point of attachment for lamellaeGill rakers remove debris from gillsLarger gill surface is often correlated with higher fish activity levels