Fig 7.48

I.Chordata A.Urochordata - Tunicates 2.Thaliacea – Salps PlanktonicPlanktonic Transparent body with radial bands of muscle for locomotionTransparent body with radial bands of muscle for locomotion Water enters through anterior incurrent siphon and is forced out through posterior excurrent siphonWater enters through anterior incurrent siphon and is forced out through posterior excurrent siphon Solitary or colonialSolitary or colonial 3.Larvacea – Appendicularians PlanktonicPlanktonic Superficially similar to tadpole larvaSuperficially similar to tadpole larva Secrete mucus “house” for protection and feedingSecrete mucus “house” for protection and feeding

Fig 15.9 Feeding Link

I.Chordata B.Cephalocordata - Lancelets Possess all chordate characteristics throughout life (no backbone)Possess all chordate characteristics throughout life (no backbone) Inhabit soft bottomsInhabit soft bottoms Suspension feeders (filter feeders)Suspension feeders (filter feeders) Gill slits used to filter particles out of waterGill slits used to filter particles out of water

Fig 7.49 Female Male

II.Vertebrata Share four chordate characteristics + vertebral column (spine, backbone)Share four chordate characteristics + vertebral column (spine, backbone) Spine encloses and protects nerve cord (spinal cord)Spine encloses and protects nerve cord (spinal cord) Anterior end of spinal cord = brain protected by skull made of bone or cartilageAnterior end of spinal cord = brain protected by skull made of bone or cartilage

III.Fishes - Overview Oldest group of vertebrates (530 mya)Oldest group of vertebrates (530 mya) 27,000+ species (15,600+ marine spp.)27,000+ species (15,600+ marine spp.) Three major groupsThree major groups Agnatha (Jawless fishes)Agnatha (Jawless fishes) Hagfishes, LampreysHagfishes, Lampreys Chondrichthyes (Cartilaginous fishes)Chondrichthyes (Cartilaginous fishes) Sharks, Rays, Skates, RatfishesSharks, Rays, Skates, Ratfishes Osteichthyes (Bony fishes)Osteichthyes (Bony fishes) Most familiar fish speciesMost familiar fish species

Fig. 8.1

III.Fishes - Overview A.Agnatha (Jawless fishes) Unpaired finsUnpaired fins Lack jawsLack jaws Round, muscular mouth with rows of teethRound, muscular mouth with rows of teeth 1.Hagfishes Scavengers (max length ~ 80 cm) – How do they feed?Scavengers (max length ~ 80 cm) – How do they feed? Dig burrows in areas with mud bottoms, usually cold waterDig burrows in areas with mud bottoms, usually cold water Attack hooked or trapped fishAttack hooked or trapped fish Capable of producing slime!!Capable of producing slime!! Very flexible (can tie selves into knots) – Why?Very flexible (can tie selves into knots) – Why? Exploited commercially – Eelskin walletsExploited commercially – Eelskin wallets 2. 2.Lampreys Most live in fresh water Attach to other fishes, rasp away sides and suck blood Also feed on benthic invertebrates

Fig. 8.2

III.Fishes - Overview A.Agnatha (Jawless fishes) Unpaired fins Lack jaws Round, muscular mouth with rows of teeth 1. 1.Hagfishes Scavengers (max length ~ 80 cm) – How do they feed? Dig burrows in areas with mud bottoms, usually cold water Attack hooked or trapped fish Capable of producing slime!! Very flexible (can tie selves into knots) – Why? Exploited commercially – Eelskin wallets 2.Lampreys Most live in fresh waterMost live in fresh water Attach to other fishes, rasp away sides and suck bloodAttach to other fishes, rasp away sides and suck blood Also feed on benthic invertebratesAlso feed on benthic invertebrates

III.Fishes - Overview B.Chondrichthyes (Cartilaginous fishes) Skeleton of cartilage (more flexible than bone)Skeleton of cartilage (more flexible than bone) Movable jawsMovable jaws Often contain well-developed teethOften contain well-developed teeth Mouth usually ventralMouth usually ventral Paired and unpaired finsPaired and unpaired fins UnpairedUnpaired DorsalDorsal CaudalCaudal AnalAnal PairedPaired PectoralPectoral PelvicPelvic Placoid scalesPlacoid scales Made of same material as teethMade of same material as teeth Fig. 8.8

III.Fishes - Overview B.Chondrichthyes (Cartilaginous fishes) 1.Sharks Fusiform bodyFusiform body Heterocercal tailHeterocercal tail Typically two dorsal finsTypically two dorsal fins Pectoral fins usually large and pointedPectoral fins usually large and pointed Five to seven gill slitsFive to seven gill slits Most sharks swim continuously to ventilate gillsMost sharks swim continuously to ventilate gills Whale shark = Largest fish species (to 60 ft)Whale shark = Largest fish species (to 60 ft) Plankton feederPlankton feeder Most prevalent in tropical coastal watersMost prevalent in tropical coastal waters Exploited and often overfishedExploited and often overfished Fins for soupFins for soup MeatMeat OilOil Skin  Abrasive, ShagreenSkin  Abrasive, Shagreen Cartilage  TherapeuticCartilage  Therapeutic

Fig. 8.4