chordates

chordates

Notochord

Pharyngeal slits

Endostyle/thyroid gland

Dorsal hollow nerve cord

Post anal tail

Cephalochordates

Lancelets/Amphioxus

Urochordates

Tunicates/Sea squirts

Vertebrates

fish, amphibian, mammals, reptiles, birds

Cephalochordates - Lancelets

Retain chordate characteristics

throughout lifetime

Urochordates – Sea Squirts/Tunicates

Have all chordate characteristics as

larvae

Keep pharyngeal slits (feeding aid) in

adulthood

Notochord

Elastic rod, flexes laterally, does not collapse

pharyngeal pouch

Walls of pharynx “push out” to form pouches

Endostyle

glandular groove on floor of pharynx

thyroid

arises from floor of pharynx

dorsal hollow nerve cord

formed by vagination folds to create tube dorsal to notochord

Postanal tail

Extension of the chordate locomotor apparatus

Balance/navigation

Courting

Communication

Defense from Predation

Flyswatter

Blanket

In humans: vestigial (coccyx)