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

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

9. Figure 13.13: The great white shark (genus Carcharodon), is a predator of seals, sea lions, and large fish. It is one of the most dangerous of sharks encountered by human swimmers. In this extraordinary photo taken off the South African coast, a large great white shark rockets from the ocean with a freshly caught sea lion in its jaws.
Fig , p. 269

10. Figure 13. 14: A diver hitches a ride on a whale shark
Figure 13.14: A diver hitches a ride on a whale shark. Unless he is struck by the fish’s tail as he dismounts, the diver is in no danger. Large animals (like seals and divers) are not part of the diet of this type of shark.
Fig , p. 269

11. 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

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

13. Bony Fish
swim bladders

14. Bony Fish
operculum

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

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

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

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

19. Figure 14.25

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

21. Seals vs. Sea Lions Sea Lions Seals 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

22. Marine Mammals Sirenia manatees & dugongs
only herbivorous marine mammal

23. 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