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Marine Fish es. Phylum Chordata. Review: Chordates. 500 mya Evolved from invertebrate chordates. Chordates Begin!!!. Post-anal Tail. Cat Human. Vertebrates. Vertebrates differ from protochordates because of BACKBONE Backbone = vertebral column or spine Made of vertebrae
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Marine Fishes Phylum Chordata
Review: Chordates • 500 mya • Evolved from invertebrate chordates Chordates Begin!!!
Post-anal Tail Cat Human
Vertebrates • Vertebrates differ from protochordates because of BACKBONE • Backbone = vertebral column or spine • Made of vertebrae • Encloses & protects nerve cord
Fish – single individual OR more than 1 individual of the same species Fishes –more than one species Fish vs. Fishes
Fish • Oldest & Most Primitive Vertebrates • 30,000 species; half the living vertebrates on earth • $$$ Important to Economy
Class Agnatha • Jawless Fishes • Most primative • Feed by suction • Have round muscular mouth • Body: Long, Lack fins, Lack scales
Class Agnatha – Hagfish or Slime eels • Eat dead or dying fish • Bore into prey and eat from inside out • Dig tunnels in mud • 3ft. long • Colder water • Skin used for Leather Goods
6 Hours Later Fresh Bait Left in Ocean
Class Agnatha – Lampreys • Temperate regions, primarily freshwater • Breed in lakes or rivers • Some adults move to ocean • Parasitic: attach to other fish & suck blood
Class Condrichthyes • Cartilaginous fish • Cartilage skeleton • Advanced Features: • Movable jaws • Ventral mouth • Paired Lateral Fins
Fast swimming & predatory feeding “Living fossils” Fished for: Meat, oil, skin, fins Many severely over fished Class Condrichthyes - Sharks • Location • Found in all oceans at all depths • Mostly coastal, warm waters • Some travel up rivers • Some live in very deep water
Class Condrichthyes – Rays and Skates • Flattened bodies • Gill slits on the ventral side • Pectoral fins flattened & expanded (wings) • Usually fused with head • Eyes on top of head
Rays • Electricrays • Organs in head that generate electricity • Up to 200 volts to stun prey and discourage predators • Eagle rays and Manta rays are pelagic • Eagle rays return to bottom to feed • Manta rays feed on plankton in mid-water • Largest ray (7 m wide!) • Whip-like tail with spines • Feed on clams, crabs, small fish, bottom dwellers • Stir sand up with pectoral fins • Teeth = plates for grinding & crushing • Strong suction
Skates • Similar to rays but lack whip-like tail & spines
Class Condrichthyes – Ratfish • Flap of skin covers gill slits • Eat crustaceans & mollusks • Deep water • Long, rat-like tail
Class Osteichthyes • Bony Fish • Skeleton at least partially bone • 21,500 species = 98 % of all fish • About 50% of all vertebrates • 2 Classes: • Actinopterygii - Ray-finned fish • Sarcopterygii - Lobe finned fish
Ray-finned Lobe-finned
Osteichthyes Adaptations • Mouth • Mouth is almost always terminal • Teeth not in rows • Swim Bladder - Gas filled sac that regulates buoyancy • Skin • Thin flexible scales • Scales covered in layer of tissue • Tissue covered with mucus • Operculum– gill cover