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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.
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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
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
Subphylum Cephalochordata • Lancelets (Amphioxus) • Notochord runs from head through tail • Muscles can contract the notochord • Live partially buried in marine sediment • Filter feeders • Dioecious