10. 10. PHYLUM CHORDATAPHYLUM CHORDATA Dorsal Notochord-Dorsal Notochord-long rod that supports the long rod that supports the

body-becomes the vertebrae in most.body-becomes the vertebrae in most. Dorsal Nerve cord-Dorsal Nerve cord-becomes the central nervous becomes the central nervous

system.system. Pharyngeal gill slits-Pharyngeal gill slits-openings in the throat for openings in the throat for

feeding & breathing-becomes the Pharynx in feeding & breathing-becomes the Pharynx in humans.humans.

TailTail-forms in embryos and extends past the anus.-forms in embryos and extends past the anus.

CLASSES OF CLASSES OF CHORDATESCHORDATES

PHYLUM CHORDATA

PISCES AMPHIBIA REPTILIA AVES MAMMALIA

CLASS PISCESCLASS PISCES

BECAUSE THEREARE 20,000 SPECIES

THERE ARE 3SUBCLASSES

SUBCLASS AGNATHA

(JAWLESS FISH)

CHONDRICHTHYES(CARTILAGE)

OSTEICHTHYES(BONY FISH)

SUBCLASS SUBCLASS

Classes of PiscesClasses of Pisces

SUBCLASS AGNATHASUBCLASS AGNATHA Jawless fish, that are Jawless fish, that are

the only vertebrate the only vertebrate parasites.parasites.

HagfishHagfish live in salt, live in salt, LampreysLampreys live in fresh live in fresh

Water.Water. Have a sucker-like Have a sucker-like

oral disk, with teeth oral disk, with teeth that rasp the flesh & that rasp the flesh & suck out juices from suck out juices from tissue.tissue.

HagfishHagfish

CARTILAGINOUS FISHCARTILAGINOUS FISH 850 Species of 850 Species of

Sharks, Rays & SkateSharks, Rays & Skate Skeleton is made of Skeleton is made of

cartilage. S-shaped cartilage. S-shaped swimming/rigid fins.swimming/rigid fins.

Gill slits.Gill slits. Store oils & constant Store oils & constant

motion to stay afloat.motion to stay afloat. Scales are small bony Scales are small bony

plates (at one time plates (at one time used as sandpaper).used as sandpaper).

RAYS & SKATESRAYS & SKATES Flattened body for a Flattened body for a

bottom-dwelling bottom-dwelling nicheniche

Spiracles & eyes on Spiracles & eyes on the dorsal side.the dorsal side.

Mouth, nostrils & Mouth, nostrils & gill slits on ventral gill slits on ventral side.side.

Stingrays have a Stingrays have a hollow barb.hollow barb.

Manta ray grows to Manta ray grows to 18’.18’.

SHARKSSHARKS Close to 300 species.Close to 300 species. Largest fish in the Largest fish in the

world-Whale Shark.world-Whale Shark. Can smell1drop/bloodCan smell1drop/blood In 1 million parts/water.In 1 million parts/water. Lateral line detect Lateral line detect

vibrations in the watervibrations in the water Ampullae of LorenziniAmpullae of Lorenzini Sense changes in Sense changes in

electrical field.electrical field.

WHALE SHARKWHALE SHARK

CLASS OSTEICHTHYESCLASS OSTEICHTHYES(BONY FISH)(BONY FISH)

96% of all fish belong to this group.96% of all fish belong to this group. Bony skeletons, gill operculum's.Bony skeletons, gill operculum's. Rigid bodies, flexible fins.Rigid bodies, flexible fins. Swim bladders for buoyancy.Swim bladders for buoyancy. Chromatophores for color.Chromatophores for color.

SKIN & SCALESSKIN & SCALES

The skin of bony fish The skin of bony fish has has chromatophoreschromatophores--mating, camouflage.mating, camouflage.

Light, flexible Light, flexible scales scales for protection.for protection.

Produce Produce mucusmucus to to reduce friction in reduce friction in water & protect water & protect against predators.against predators.

FINS & LOCOMOTIONFINS & LOCOMOTION

Due to the rigid Due to the rigid nature of their body, nature of their body, bony fish “flex” their bony fish “flex” their fins for propulsion.fins for propulsion.

Paired fins are for Paired fins are for fine movements.fine movements.

Dorsal & Ventral are Dorsal & Ventral are used to stabilize.used to stabilize.

Caudal is for speed!Caudal is for speed!

SWIM BLADDER & SWIM BLADDER & GILLSGILLS

Swim/air bladder-gas filled sac that can be Swim/air bladder-gas filled sac that can be used for buoyancy, sound & protection.used for buoyancy, sound & protection.

Gills extract Oxygen efficiently from water.Gills extract Oxygen efficiently from water. Covered by an operculum, there are 3 Covered by an operculum, there are 3

partsparts-gill raker, gill arch & gill filaments-gill raker, gill arch & gill filaments.. Blood flow in the filaments is opposite the Blood flow in the filaments is opposite the

flow of water resulting in the greatest flow of water resulting in the greatest amount of gas exchange!amount of gas exchange!

BONY FISH ANATOMYBONY FISH ANATOMY

GILL EFFICIENCYGILL EFFICIENCY

Counter-flow efficiencyCounter-flow efficiency

BloodBlood WaterWater

100%100%20%20%

30%35%40%45%50%55%60%

30%35%40%45%50%55%60%

90%85%80%75%70%65%60%

90%85%80%75%70%65%60%

ConcurrentConcurrentexchangeexchange

ConcurrentConcurrentexchangeexchange

Fluids flow in Fluids flow in the same the same directiondirection

equilibrium equilibrium between the two between the two fluids occursfluids occurs

Fluids flow in Fluids flow in the same the same directiondirection

equilibrium equilibrium between the two between the two fluids occursfluids occurs

BloodBlood WaterWater

100%100%

20%20%

30%40%50%60%70%80%90%

30%40%50%60%70%80%90%

30%40%50%60%70%80%90%

30%40%50%60%70%80%90%

Counter Counter CurrentCurrent

ExchangeExchange

Counter Counter CurrentCurrent

ExchangeExchange Fluids flow in the Fluids flow in the

opposite opposite directionsdirections

Equilibrium Equilibrium between the two between the two fluids never fluids never occursoccurs

Fluids flow in the Fluids flow in the opposite opposite directionsdirections

Equilibrium Equilibrium between the two between the two fluids never fluids never occursoccurs

LATERAL LINELATERAL LINE Lateral line is a series of pits Lateral line is a series of pits

on the side of a fish that on the side of a fish that lead directly to spinal cord.lead directly to spinal cord.

It can sense the slightest It can sense the slightest movements in the water. movements in the water. (vibrations)(vibrations)

SchoolingSchooling: fish use this : fish use this sense to school..(about 80 % sense to school..(about 80 % of all species school at one of all species school at one time)time)

Schooling helps with: Schooling helps with: mating,mating,

Protection in #’s, Protection in #’s, disruptive.disruptive.

REPRODUCTIONREPRODUCTION

OviparousOviparous-both -both sexes spawn & sexes spawn & eggs are fertilized eggs are fertilized externally.externally.

Ovoviparous-Ovoviparous-some some incubate the eggsincubate the eggs

ViviparousViviparous-some -some species actually species actually bear their young bear their young live!live!

MigrationsMigrations

CatadromousCatadromous- - Breed in the Breed in the oceans but live in oceans but live in freshwaterfreshwater

Eels migrate to Eels migrate to the Sargasso Sea, the Sargasso Sea, they spawn at they spawn at depths of 300 depths of 300 meters and die meters and die when donewhen done

AnadromousAnadromous- - Breed in Breed in freshwater but live freshwater but live in saltin salt

Atlantic Salmon Atlantic Salmon makes multiple makes multiple trips in its lifetimetrips in its lifetime

Pacific Salmon Pacific Salmon only onceonly once

SYMBIOSISSYMBIOSIS