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What Makes a Fish a Fish?. Chapter 8: Marine Fishes. Fish are Vertebrates…. 1. Backbone – called a vertebral column or spine Dorsal row of hollow skeletal elements (usually bone) called vertebrae 2. Nerve Cord/Spinal Cord Protected by vertebrae Ends at the brain 3. Bilateral Symmetry
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What Makes a Fish a Fish? Chapter 8: Marine Fishes
Fish are Vertebrates… 1. Backbone – called a vertebral column or spine • Dorsal row of hollow skeletal elements (usually bone) called vertebrae 2. Nerve Cord/Spinal Cord • Protected by vertebrae • Ends at the brain 3. Bilateral Symmetry 4. Endoskeleton
What Makes a Fish a Fish? A fish is an organism that… • is aquatic, • exchanges oxygen using gills, • is covered with scales, • and has paired fins.
Background • Oldest, structurally simplest vertebrates • Most abundant vertebrates • At least 30,000 species • Phylum: Chordata • Subphylum: Vertebrata • Class: Agnatha – jawless fishes • Class: Chondrichthyes – sharks, rays, ratfish • Class: Osteicthyes – bony fishes