Chordata (Fishes)Agnatha, Chnondrichthyes, Osteichtheys

Movement, Shape, PropulsionLeveling

Feeding and Defense

Class Agnatha Includes Hagfish and LampreysAgnatha means lacking a jaw (jawless fish)Evolved firstSkin has fibrous layers used for “eelskin” leather goods

sold in upscale stores in South Korea. Also quite slimy (a defense mechanism)Hagfish eat mostly worms or scavangeLampreys attach to other fish and eat flesh and blood kind

of like a vampire and then detach before killing the host.

Jawless FishLamprey Hagfish

Class ChondrichthyesIncludes sharks, skates, and raysChondrichthyes means cartilage fish (same stuff

that makes up your ears and tip of your nose). Only bones are jaws and teethSharks are largest living vertebrates

Skates and Rays Flattened bodies Wing-like fins No gas bladder: will sink if they

stop swimming. Sting rays have a venomous barb

on their tail for defense. Giant manta rays can be 22 feet

across! Some rays can produce electric

shock to stun prey or disable a human.

Eat plankton, mollusks (squid), and arthropods that they crush with their plate-like jaws.

Sharks Only kill about 6 people a

year. Mostly mistaken for seals.

More people killed by dogs Still, humans kill 16 million

sharks per year. Mostly for food or medicine.

Great White Shark is largest (22 feet long!)

Can smell blood miles away.

Class OsteichthyesMeans bony fish27,000 speciesHave a hard, strong, lightweight skeletonFound in almost every marine habitat from tide

pools to abyssal plains. Includes lungfishes and lobe-finned coelacanths

which evolved into land vertebrates

Order TeleosteiMeans perfect bone90% of all bony fish Includes Cod, Tuna, Halibut, Perch, Sunfish, Lionfish, Sea

Horses, eels, and many others. Have gas-filled swim bladders for staying afloat Independently moveable fins for locomotionEffective camouflageGreat speedOften swim in groups called schools

Economic ImportanceMulti-Billion dollar a year industryOver 70 million tons of bony fishes are taken

from the ocean annually. Great source of protein

Movement, Shape, Propulsion

Fish move by combining body movement with fin movement.

A teardrop shape is the best for swimming fast. (Tuna have this shape).

Swordfish and Marlin can swim up to 75 miles per hour in short bursts!!!

Maintenance of LevelMost fish have gas-filled swim bladders just below the

spine that keeps them afloat.Sharks and Rays do not and have to swim continuously.More gas means fish moves upward, and less gas

means fish moves downward.Quantity of gas is controlled by secretion and absorption

of gas from the blood and by muscular contractions.Tuna, Mackeral, and Swordfish must be able to chase

prey between depths quickly and therefore lack swim bladders. Quick changes may rupture a swim bladder.

Feeding and DefenseFish have great eyesight and great hearingA lateral-line system of small canals in the skin

and bones around the eyes and down the side of the body detect low-frequency vibrations.

Nerves report changes in current direction and water pressure.

Armor, inflation, camouflage, schooling, and jumping.