Chordate Characteristics

The following adaptations are present in all chordates: notochord, dorsal hollow nerve cord, pharyngeal slits and a muscular postanal tail. A notochord is a primitive backbone.  The hollow nerve cord develops from the ectoderm and then rolls into a tube right below the notochord.  Pharyngeal slits filter food(or oxygen in fishes) from water: the chordate gulps in water through its mouth (or analogous structure) water passes through tiny slits in a membrane filtering out large particles that are most likely food.  Most nonchordates have a digestive tract running the entire length of their bodies.

Next:  "Subphyla."