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Chordata (Fishes)

Chordata (Fishes). Agnatha , Chnondrichthyes , Osteichtheys Movement, Shape, Propulsion Leveling Feeding and Defense. Class Agnatha. Includes Hagfish and Lampreys Agnatha means lacking a jaw (jawless fish) Evolved first

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Chordata (Fishes)

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  1. Chordata (Fishes) Agnatha, Chnondrichthyes, Osteichtheys Movement, Shape, Propulsion Leveling Feeding and Defense

  2. 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.

  3. Jawless Fish Lamprey Hagfish

  4. 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 vertebrates

  5. 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.

  6. 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.

  7. 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 vertebrates

  8. 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

  9. Economic Importance • Multi-Billion dollar a year industry • Over 70 million tons of bony fishes are taken from the ocean annually. • Great source of protein

  10. 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!!!

  11. 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.

  12. 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.

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