PHYLUM CHORDATA notochord dorsal, hollow nerve tube gill slits post anal tail

Two Invertebrate Chordates Urochordates –sea squirts or tunicates Cephalochordates –lancelets or amphioxus

VERTEBRATES Possess backbones – replaces the notochord

Jawless Fish – Class Agnatha hagfish lamprey

Cartilagenous Fish – Class Chondrichthyes skates, rays and sharks

Class Chondrichthyes

Cartilagenous Fish – Class Chondrichthyes skeletons made of tough elastic cartilage negatively buoyant some of the active sharks must swim to breathe

Bony Fish – Class Osteichthyes most numerous and successful of all vertebrates

Bony Fish – Class Osteichthyes swim bladders countercurrent exchange operculum body shape effects the efficiency of movement

Amphibians not found in marine environments

Marine Reptiles Sea turtles, sea snakes, marine iguanas, marine crocodiles

Figure 9.05 Marine iguana – 1 of 2 marine reptiles (other = crocodile)

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

Marine Birds Class Aves Albatrosses, pelicans, gulls, terns, puffins and penguins are endotherms, also have salt secreting glands

Marine Mammals mammary glands hair endothermic streamlined bodies

Marine Mammals breathe air using lungs modified respiratory & circulatory system system osmotic adaptations

Marine Mammals Cetaceans –porpoises, dolphins and whales

Humpback Whale

Beluga Whale

Bottlenose Dolphin

Marine Mammals There are 3 groups –#1 Pinnipeds (sea lions, seals and walruses)

Elephant Seals

Figure 9.11

Marine Mammals #2 Sirenia –manatees- only herbivorous marine mammal

Marine Mammals #3 Carnivora –seals, sea lions, walruses, sea otters and polar bears