Fig 7.48

I.I. ChordataChordata

A.A. Urochordata - TunicatesUrochordata - Tunicates2.2. Thaliacea – SalpsThaliacea – Salps

• PlanktonicPlanktonic• Transparent body with radial bands of muscle Transparent body with radial bands of muscle

for locomotionfor locomotion• Water enters through anterior incurrent Water enters through anterior incurrent

siphon and is forced out through posterior siphon and is forced out through posterior excurrent siphonexcurrent siphon

• Solitary or colonialSolitary or colonial

3.3. Larvacea – AppendiculariansLarvacea – Appendicularians• PlanktonicPlanktonic• Superficially similar to tadpole larvaSuperficially similar to tadpole larva• Secrete mucus “house” for protection and Secrete mucus “house” for protection and

feedingfeeding

Fig 15.9

FeedingLink

I.I. ChordataChordata

B.B. Cephalocordata - LanceletsCephalocordata - Lancelets• Possess all chordate characteristics Possess all chordate characteristics

throughout life (no backbone)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.II. VertebrataVertebrata

• Share four chordate characteristics + Share four chordate characteristics + vertebral column (spine, backbone)vertebral column (spine, backbone)

• Spine encloses and protects nerve cord Spine encloses and protects nerve cord (spinal cord)(spinal cord)

• Anterior end of spinal cord = Anterior end of spinal cord = brainbrain protected by protected by skullskull made of bone or made of bone or cartilagecartilage

III.III. Fishes - OverviewFishes - Overview

• Oldest group of vertebrates (530 Oldest group of vertebrates (530 mya)mya)

• 27,000+ species (15,600+ marine 27,000+ species (15,600+ marine spp.)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.III. Fishes - OverviewFishes - Overview

A.A. Agnatha (Jawless fishes)Agnatha (Jawless fishes)• Unpaired finsUnpaired fins• Lack jawsLack jaws

• Round, muscular mouth with rows of teethRound, muscular mouth with rows of teeth

1.1. HagfishesHagfishes• Scavengers (max length ~ 80 cm) – Scavengers (max length ~ 80 cm) – How do they How do they

feed?feed?• Dig burrows in areas with mud bottoms, usually cold Dig burrows in areas with mud bottoms, usually cold

waterwater• Attack hooked or trapped fishAttack hooked or trapped fish• Capable of producing slime!!Capable of producing slime!!• Very flexible (can tie selves into knots) – Very flexible (can tie selves into knots) – Why?Why?• Exploited commercially – Eelskin walletsExploited commercially – Eelskin wallets

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.III. Fishes - OverviewFishes - Overview

A.A. Agnatha (Jawless fishes)Agnatha (Jawless fishes)• Unpaired fins• Lack jaws

• Round, muscular mouth with rows of teeth

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

2.2. LampreysLampreys• 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.III. Fishes - OverviewFishes - Overview

B.B. Chondrichthyes (Cartilaginous fishes)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

• PlacoidPlacoid scales scales• Made of same material as teethMade of same material as teeth

Fig. 8.8

III.III. Fishes - OverviewFishes - Overview

B.B. Chondrichthyes (Cartilaginous fishes)Chondrichthyes (Cartilaginous fishes)1.1. SharksSharks

• FusiformFusiform body body• HeterocercalHeterocercal tail tail• Typically two dorsal finsTypically two dorsal fins• Pectoral fins usually large and pointedPectoral fins usually large and pointed• Five to seven Five to seven gill slitsgill slits

• Most sharks swim continuously to ventilate gillsMost sharks swim continuously to ventilate gills• Whale sharkWhale shark = Largest fish species (to 60 ft) = 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 Skin Abrasive, Shagreen Abrasive, Shagreen• Cartilage Cartilage Therapeutic Therapeutic

Fig. 8.4