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 BirdsClass 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

BottlenoseDolphin

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