Phylum Chordata

Invertebrate Chordates Ex. Tunicates/Sea Squirts Ex. Lancelet

Fishes Ectotherms (cold-blooded) Lay eggs without a shell External fertilization

Jawless Fish Cartilage skeleton; no jaws Ex. Lamprey, hagfish

Cartilage Fish Jaws and cartilage skeletons Ex. Sharks, rays and skates

Bony Fish Have jaws and a bony skeleton Have a swim bladder that allows them to float at different depths Most fish are in this group—perch, eel, trout

Amphibians Ectothermic, external fertilization, eggs have no shell Ex. Toads, (thick bumpy skin with poison glands) frogs, newts and salamanders

Reptiles Ectothermic, eggs with a shell, internal fertilization 3 chambered heart (except crocodiles have 4) Amniotic Egg

Birds Endothermic (warm-blooded), internal fertilization, amniotic eggs Build nests to incubate eggs Air sacs to increase O2

Mammals Endothermic, mammary glands, hair, sweat glands, 4 chambered heart, diaphragm Divided into 3 groups based on how they reproduce

Monotremes: lay eggs, ex. Platypus, echidna

Marsupials: carry immature young in a pouch, ex. Kangaroo, opossum

Placentals: carry young in uterus— includes most mammals.