1. Phylum Chordata

2. Invertebrate Chordates Ex. Tunicates/Sea Squirts Ex. Lancelet

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

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

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

6. 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

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

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

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

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

18. Monotremes: lay eggs, ex. Platypus, echidna

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

20. Placentals: carry young in uterus— includes most mammals.