Urochordata - Research Article from Macmillan Science Library: Animal Sciences

This encyclopedia article consists of approximately 2 pages of information about Urochordata.

Urochordata - Research Article from Macmillan Science Library: Animal Sciences

This encyclopedia article consists of approximately 2 pages of information about Urochordata.
This section contains 495 words
(approx. 2 pages at 300 words per page)
Buy the Urochordata Encyclopedia Article

Urochordates are small marine animals with larvae that swim freely and adults that attach themselves to the ocean floor. The 1,300 species of urochordates, like all members of the phylum Chordata, possess four characteristic anatomical structures as embryos: a flexible body-length rod (the notochord) that provides resistance against muscular contractions and allows for more efficient movement; a dorsal, hollow, nerve cord that forms the central nervous system; slits in the beginning of the digestive tract (the pharynx) that allow filter feeding and gas exchange; and a postanal tail. Urochordates, commonly known as tunicates, differ from other chordate subphyla (Cephalochordata and Vertebrata) in that the adult form has no notochord, nerve cord, or tail. In fact, an adult tunicate is an immobile, filter-feeding marine animal that in some ways looks more like a sponge or a mollusk than a chordate.

Tunicate larvae look much more like other chordates than adult...

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This section contains 495 words
(approx. 2 pages at 300 words per page)
Buy the Urochordata Encyclopedia Article
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Urochordata from Macmillan. Copyright © 2001-2006 by Macmillan Reference USA, an imprint of the Gale Group. All rights reserved.