17.2 Fish


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17.2 Fish

  1. 1. 17.2 FISHES<br />Page 348<br />
  2. 2. Gills<br />Organs that remove dissolved oxygen from water<br />Located on either side of fish’s head<br />
  3. 3. Gills<br />
  4. 4. How Gills Work<br />Water passes over gills as a fish swims<br />Oxygen in the water diffuses into cells at the surface of the gills<br />As this happens, carbon dioxide diffuses out of blood vessels into the water<br />
  5. 5. Characteristics of Fish<br />All fish are ectotherms<br />Most have streamlined bodies and use fins for movement<br />Most have excellent sense of smell<br />All have highly developed nervous systems<br />
  6. 6. 3 Classes of Fish<br />Jawless Fish {Agnatha}<br />Cartilaginous Fish {Chondrichthyes}<br />Bony Fish {Osteichthyes}<br />
  7. 7. Jawless Fish <br />Vertebrates (have backbone)<br />Lack jaws<br />Probably filter feeders<br />Only a few species exist today<br />Lampreys & Hagfish<br />Parasites – their mouth is a sucker used to attach to “hosts” and feed<br />
  8. 8. Jawless Fish <br />LAMPREY<br />HAGFISH<br />
  9. 9. Cartilaginous Fish<br />Cartilage: firm, but flexible, connective tissue<br />Cartilaginous fish have skeletons made completely of cartilage<br />Have jaws<br />Most are carnivores – sharp teeth & senses <br />Some are filter feeders (whale shark)<br />
  10. 10. Cartilaginous Fish<br />Some are filter feeders (whale shark)<br />Bodies are more dense than water – must keep swimming to stay off ocean floor<br />Swimming also creates current of water which passes over gills – supplies fish with oxygen<br />
  11. 11. Cartilaginous Fish Examples<br />SHARK<br />STINGRAY<br />WHALE SHARK<br />
  12. 12. Bony Fish <br />Greatest number of fish belong to this class<br />Have skeletons made of bone<br />
  13. 13. Bony Fish Examples<br />CATFISH<br />SALMON<br />GOLDFISH<br />
  14. 14. Bony Fish Anatomy<br />Swim Bladder<br />Helps conserve energy<br />Similar to a balloon<br />Used to adjust their depth<br />Inflating the bladder with right amount of air keeps fish from sinking<br />
  15. 15. Bony Fish Anatomy<br />
  16. 16. Buoyancy<br />Buoyancy: force of liquid pushing an object up<br />If the weight of an object….<br />Is greater than the buoyant force, it will sink<br />Is less than buoyant force, it will float<br />Is equal to the buoyant force, it will stayat any level (FISH)<br />
  17. 17. Buoyancy Illustrated<br />BUOYANCY: force of liquid pushing an object up<br />
  18. 18. Bony Fish Anatomy…<br />Scales & Fins<br />Outside covered with layer of smooth scales<br />Overlap each other<br />Scales covered with thin layer of mucus<br />Scales and mucus are adaptations that help fish move through water<br />Fins are adapted for swimming and guiding the fish<br />
  19. 19. Scales<br />Scales and mucus are adaptationsthat help fish move through water<br />
  20. 20. Gills & Lungs<br />Bony fish DON’T need to swim to move water over gills (cartilaginous fish DO)<br />Have ability to pump water through mouth into the gill chamber<br />MOST bony fish depend only on gills, some on both gills and lungs<br />These fish must swim to surface of water for oxygen<br />
  21. 21. Gills & Lungs<br />The African Lungfish has both gills and lungs<br />