Fishes Agnatha Chnondrichthyes Osteichtheys Movement Shape Propulsion Leveling Feeding and Defense Class Agnatha Includes Hagfish and Lampreys Agnatha means lacking a jaw jawless fish ID: 225546
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Slide1
Chordata (Fishes)
Agnatha
,
Chnondrichthyes
,
Osteichtheys
Movement, Shape, Propulsion
Leveling
Feeding and DefenseSlide2
Class Agnatha
Includes Hagfish and Lampreys
Agnatha
means lacking a jaw (jawless fish)
Evolved first
Skin 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
scavange
Lampreys attach to other fish and eat flesh and blood kind of like a vampire and then detach before killing the host. Slide3
Jawless Fish
Lamprey
HagfishSlide4
Class Chondrichthyes
Includes sharks, skates, and rays
Chondrichthyes
means cartilage fish (same stuff that makes up your ears and tip of your nose).
Only bones are jaws and teeth
Sharks are largest living vertebratesSlide5
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. Slide6
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. Slide7
Class Osteichthyes
Means bony fish
27,000 species
Have a hard, strong, lightweight skeleton
Found in almost every marine habitat from tide pools to abyssal plains.
Includes lungfishes and lobe-finned coelacanths which evolved into land vertebratesSlide8
Order Teleostei
Means perfect bone
90% 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 locomotion
Effective camouflage
Great speed
Often swim in groups called schools Slide9
Economic Importance
Multi-Billion dollar a year industry
Over 70 million tons of bony fishes are taken from the ocean annually.
Great source of proteinSlide10
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!!!Slide11
Maintenance of Level
Most 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. Slide12Slide13
Feeding and Defense
Fish have great eyesight and great hearing
A 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.