Invertebrate Chordates Hemichordata Urochordata Cephalochordata
Hemichordates Deuterostomes Gill slits Dorsal nerve cord
Classes of Hemichordates Enteropneusta Acorn worms Shallow marine animals Pterobranchia Rhabdopleura Colonial, send out feeding zooids
Acorn Worm
Phylum Chordata All chordates are deuterostomes At some time in their life, all chordates have: Notochord Pharyngeal gill slits Dorsal, hollow nerve cord Postanal tail
Subphylum Urochordata Sea squirts or tunicates Larvae show the characteristics of chordates Adults lose notochord, nerve cord, and tail Only animals to have cellulose in their bodies!
Tunicates: Are filter feeders Do not have complex nervous systems Often form large colonies Are monoecious
Tunicate Larva
Adult tunicates
Subphylum Cephalochordata Lancelets (Amphioxus) Notochord runs from head through tail Muscles can contract the notochord Live partially buried in marine sediment Filter feeders Dioecious