Chordata (45,000 Species)

Chordate characteristics

     -Bilaterally symmetrical

     -Deuterostomates

     -At one point in their lives they have each of these 4 things

        -Notochord

        -Pharyngeal slits

        -Dorsal tubular nerve cord

        -Postanal tail

    -Presence of endostyle or thyroid gland

    -Complete digestive tract

    -Ventral, contractile blood vessel (heart)

Vertebrates

Three classes of Fish

    Class Agnatha

        -Hagfish (30 species)

        -Lampreys (35 species)

        Class Chondrichthyes (Sharks, rays, chimaeras) (1,000 species)

    Class Osteichthes

        The Boney Fish (27,000 species)

    Clade Tetrapods (29,000 species)

Class Amphibians

            -Order Caecilians (No legs)

            -Order Caudata (Salamanders) (retain their tail as adults)

            -Order Anura (Frogs) (lack tails as adults)

                -Toads- terrestrial frog

    Clade Amniotes (have amniotic eggs)

Class Reptiles

            -Order Crocodilians (23 species)

            -Order Testudines (Turtles) (307 species)

                -Tortoise- terrestrial turtle

            -Order Sphenodontida (Tuataras) (2 species)

            -Order Squamates (Snakes and lizards) (7,910 species)           

    Class Aves /Birds (10,000 species)

        Class Mammals

            -Order Monotremes (Lay eggs) (5 species)

            -Infra-Class Marsupials (Mammals with a pouch) (324 species)

            -Clade Eutherians (Placental mammals) (5,010 species)