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Nekton PowerPoint Presentation

Nekton

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Nekton

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  1. Nekton • Strong swimmers in the pelagic realm

  2. Cephalopod Mollusks • Pelagic = squid, cuttlefish, chambered nautilus • (benthic = octopus) • Have tentacles and are active predators • Highly evolved nervous system • Largest of the invertebrates (59 ft squid)

  3. cuttlefish chambered nautilus

  4. Squid

  5. Giant Squid Captured, Filmed for First Time : Dec 22, 2006- Japan

  6. Vertebrates:Cartilaginous Fish – • Skeletons made of cartilage • skates, rays • more benthic • Dorsoventrally flattened • sharks • More pelagic • Torpedo shaped and streamlined

  7. Fig. 13-13, p. 269

  8. Fig. 13-14, p. 269

  9. Cartilaginous Fish • skeletons made of tough elastic cartilage • negatively buoyant • Use fins for lift • Store oil in liver • Gill slits are visible • some of the active sharks must swim to breathe

  10. Vertebrates: Bony Fish • Skeletons made of bone • most numerous and successful of all vertebrates

  11. Bony Fish • swim bladders

  12. Bony Fish • operculum

  13. Vertebrates: Marine Reptiles • Sea turtles, sea snakes, marine iguanas, marine crocodiles

  14. Marine Reptiles • ectothermic • covered with scales • breathe air with lungs, • have specialized salt glands to excrete excess salt taken in from seawater

  15. Vertebrates: Marine Mammals • Class Mammalia • mammary glands; hair • endothermic

  16. Marine Mammals • Cetaceans • porpoises, dolphins and whales • toothed whales & baleen whales

  17. Figure 14.25

  18. Marine Mammals • Carnivora • seals, sea lions, walruses, sea otters and polar bears

  19. Seals vs. Sea Lions Sea Lions • external ear flaps • Large front flippers to propel themselves • Long neck Seals • Pin hole for ear • Small front flippers with claws • Propel themselves with rear flippers • Less mobile on land • Figure 14.18

  20. Marine Mammals • Sirenia • manatees & dugongs • only herbivorous marine mammal

  21. Marine Mammals • streamlined bodies • breathe air using lungs • modified respiratory (get 90% of O2 out of the air) & circulatory system (more red blood cells, more hemoglobin and myoglobin) for prolonged dives • osmotic adaptations