FISH

CLASSIFICATION• KINGDOM ANIMALIA• PHYLUM CHORDATA• SUBPHYLUM VERTEBRATA (BACK BONE

PRESENT)• SUPRACLASS AGNATHA (JAWLESS FISH)

• CLASS MYXINI (HAGFISH)• CLASS CPHALOSPIDOMORPHI (LAMPREY)

• SUPRACLASS GNATHOSTOMATA (JAWED FISH)• CLASS CHONDRICHTHYES (CARTILAGINOUS

FISH)• CLASS OSTEICHTHYES (BONY FISH)

PHYLUM CHORDATAFIVE CHARACTERISTICS OF CHORDATES

•1. HOLLOW NERVE CORD- IN VERTEBRATES IT DIFFERENTIATES INTO BRAIN AND SPINAL CORD

•2. NOTOCHORD- FLEXIBLE ROD PRESENT AT ONE STAGE IN ALL CHORDATES; IN VERTEBRATES IT DIFFERENTIATES INTO VERTEBRAL COLUMN THAT FORMS AROUND THE NERVE CORD

•3. PHARYNGEAL SLITS - POUCHES THAT CONNECT PHARYNX WITH OUTSIDE (BETWEEN MOUTH AND ESOPHAGUS). GILLS IN SHARKS, FISH; PRESENT IN TERRESTRIAL ANIMAL EMBRYOS BUT DISAPPEAR LATER EXCEPT EUSTACHIAN TUBE (CONNECTING THROAT AND MIDDLE EAR)

•4. POSTANAL TAIL- EXTENDS BEYOND ANUS; PRESENT AT LEAST IN EMBRYO; REGRESSES INTO TAIL BONE IN HUMANS

•5. SEGMENTATION- REFLECTED IN ARRANGEMENT OF MUSCLES & IN VERTEBRAL COLUMN

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SUPRACLASS AGNATHA(JAWLESS FISH)

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Class Cephalspidomorphi (Lamprey)•Parasite•attaches to other fish & sucks their blood•lives in ocean

Class Myxini (Hagfish)•Scavenger•lives in the ocean•known for its slimy secretions

Both have cartilaginous skeletons and sucker-like

mouths

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SUPRACLASS GNATHOSTOMATA

(JAWED FISHES)

CLASS CHONDRICHTHYES (SHARKS & RAYS)

• HAVE SKELETONS MADE OF CARTILAGE NOT BONES (HAVE BONE JAW).

• MOST SALTWATER/ VERY FEW FRESHWATER• HAVE NO OPERCULUM (GILL COVER) • SOME MUST KEEP MOVING TO BREATHE & OTHERS CAN PUMP

WATER OVER THEIR GILLS• SPIRACLE- A MODIFIED SLIT BEHIND THE EYE, ASSISTS THE

SHARK WITH TAKING IN WATER DURING RESPIRATION AND PLAYS A MAJOR ROLE IN BOTTOM DWELLING SHARKS.

• HAVE DIFFERENT KINDS OF SCALES THAT FEEL AND LOOK MORE LIKE SANDPAPER.

• MULTIPLE ROWS OF REPLACEMENT TEETH THAT STEADILY MOVE FORWARD LIKE A CONVEYOR BELT. SHARKS CAN LOSE UP TO 30,000 OR TEETH IN THEIR LIFETIME. 

• MOST SHARKS ARE COLD BLOODED• CONTROL BUOYANCY WITH LARGE LIVERS THAT EXCRETE OIL

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CLASS CHONDRICHTHYES (SHARKS & RAYS)

REPRODUCTION

•VIPAROUS- LIVE BIRTH

•VIVIPAROUS- EGGS HATCH INTERNALLY

•OVOVIVIPAROUS- LAY EGG CASES EXTERNALLY

(CALLED MERMAID’S PURSE)

•SEPARATE SEXES

•MALES HAVE CLASPERS

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CLASS CHONDRICHTHYES (SHARKS & RAYS)

SENSORY

•AMPULLAE OF LORENZINI- ELECTRORECEPTOR ORGANS USED TO DETECT THE ELECTROMAGNETIC FIELDS ALL LIVING THINGS PRODUCE. THEY NUMBER IN THE HUNDREDS TO THOUSANDS.

•LATERAL LINE SYSTEM- DETECTS MOTION OR VIBRATIONS IN WATER

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GENERAL ANATOMY OF A SHARK

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GENERAL ANATOMY OF A RAY

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Basking Shark is a filter feeder

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CLASS OSTEICHTHYES (BONY FISH)

• BACKBONE MADE OF BONE

• FRESHWATER & SALTWATER

• GILLS WITH OPERCULUM (FEW HAVE LUNGS)

• FINS - DORSAL, CAUDAL, PECTORAL, PELVIC, ANAL.

• SWIM BLADDER- A GAS FILLED SAC THAT HELPS THE FISH MAINTAIN BUOYANCY. SHARKS DON’T HAVE A SWIM BLADDER

• LATERAL LINE SYSTEM

TYPES OF OSTEICHTHYESRAY FINNED:

– MOST FISH ARE THIS TYPE– FINS ARE SUPPORTED BY BONY

STRUCTURES CALLED RAYS.

LOBE FINNED:– FINS ARE LONG, FLESHY,

MUSCULAR, SUPPORTED BY CENTRAL CORE OF BONES.

– THOUGHT TO BE ANCESTORS OF AMPHIBIANS.

– EXAMPLES ARE: COELACANTH, LUNGFISH

FINS

ADAPTATIONS SWIM R BLADDER OPERCULUM

LATERAL LINE SYSTEM

Swim Bladder

FISH ANATOMY

RESPIRATION• WATER FLOWS OVER GILLS

AS FISH OPENS MOUTH AND SWIMS.

• WATER FLOWS OPPOSITE DIRECTION OF BLOOD FLOW.

• O2 DIFFUSES FROM THE

WATER INTO THE BLOOD.

• GILLS ARE MADE OF THOUSANDS OF GILL FILAMENTS.

• GILLS ARE COVERED BY THE OPERCULUM.

CIRCULATION• FISH HEART HAS 2 CHAMBERS

• SINGLE LOOP CIRCULATION

• BLOOD FLOWS INTO GILLS, PICKS UP O2, GOES TO THE

BODY, RETURNS TO THE HEART.

REPRODUCTION• MOST FISH REPRODUCE SEXUALLY, AND

FERTILIZE THEIR EGGS EXTERNALLY

• SPAWNING IS THE PROCESS OF FERTILIZING EGGS.

• BABY FISH ARE CALLED FRY.

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Coelacanth: living fossil, lobe-finned

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Cichlids

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Clown Fish (Nemo)

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Kissing Fish

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37The puffer fish uses air to expand its body to look intimidating to predators

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Fugu (Japan): Despite precise preparation by specially qualified chefs, this toxic puffer fish delicacy kills people every year.The emperor of Japan isn't allowed to eat fugu lest it be his last meal. For all that work and risk, it still tastes like fish, but many people respect the chefs.