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Nekton. Strong swimmers in the pelagic realm. 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). cuttlefish. chambered nautilus. Squid.
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Nekton • Strong swimmers in the pelagic realm
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)
cuttlefish chambered nautilus
Giant Squid Captured, Filmed for First Time : Dec 22, 2006- Japan
Vertebrates:Cartilaginous Fish – • Skeletons made of cartilage • skates, rays • more benthic • Dorsoventrally flattened • sharks • More pelagic • Torpedo shaped and streamlined
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
Vertebrates: Bony Fish • Skeletons made of bone • most numerous and successful of all vertebrates
Bony Fish • swim bladders
Bony Fish • operculum
Vertebrates: Marine Reptiles • Sea turtles, sea snakes, marine iguanas, marine crocodiles
Marine Reptiles • ectothermic • covered with scales • breathe air with lungs, • have specialized salt glands to excrete excess salt taken in from seawater
Vertebrates: Marine Mammals • Class Mammalia • mammary glands; hair • endothermic
Marine Mammals • Cetaceans • porpoises, dolphins and whales • toothed whales & baleen whales
Marine Mammals • Carnivora • seals, sea lions, walruses, sea otters and polar bears
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
Marine Mammals • Sirenia • manatees & dugongs • only herbivorous marine mammal
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