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Ichthyes: The Fish

Ichthyes: The Fish. What is a Fish? Aquatic vertebrate, usually with paired fins, scales and gills. -fins for movement -scales for protection -gills for respiration -Very diverse group composed of many classes of fish. -. Evolution of Fish -Fish were the first vertebrates

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Ichthyes: The Fish

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  1. Ichthyes: The Fish

  2. What is a Fish? • Aquatic vertebrate, usually with paired fins, scales and gills. • -fins for movement • -scales for protection • -gills for respiration • -Very diverse group composed of many classes of fish. • -

  3. Evolution of Fish -Fish were the first vertebrates -Two important developments : - jaws - paired fins The First Fish -Strange, jawless animals with bone armour. -Lived 500 million years ago and didn’t change for 100 million years

  4. The Age of Fish -400 million years ago -all were jawless -both soft-skinned and armoured fish appeared

  5. The Arrival Of Jaws and Paired Fins

  6. Jaws -allowed fish to eat new types of food -gave them protection Paired Fins -paired pectoral and pelvic fins -fins attached to girdles, b0ne structures in the body -fish could now swim quickly, hunt and protect themselves

  7. ModernFish Agnatha: jawless fish http://www.youtube.com/watch?v=Bb2EOP3ohnE Chondrichthyes: cartilage fish Osteichthyes: Bony fish

  8. Feeding • every mode of feeding • Some will eat anything, others are very specialized • Food: • Enters mouth • Into esophagus • Stomach • Broken down further in the Pyloric Seca • Intestine • Anus • Respiration • Most fish move water over their gills and take out the oxygen • Most fish have a single gill opening protected by the operculum • Lungfish have organs like lungs and can breathe air

  9. Circulation • Closed circulatory system (blood is in vessels) • A heart moves the blood in a loop around the body: heart-gills-body-heart • Complex, four-chambered heart • Excretion • -Waste is removed in the form of ammonia • Kidneys help fish control the water in their bodies • Response • -Well-developed brain with different parts • -Most fish have good sense organs • -Lateral Line System lets fish feel movement in the water

  10. Movement: -muscles bend their bodies in a S-shaped movements -fish move forward -fins stabilize and steer -body is streamlined -many fish have a swim bladder to help them float

  11. Reproduction -can be either internal or external fertilization -fish that hatch from eggs are oviparous

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