notochord
All chordates possess a notochord at some time during their lives. Though replaced by cartilage or bone in the adult vertebrate and absent in the adults of other chordate groups, e.g., tunicates, it is well developed in the embryos and larvae of all these groups, confirming evolutionary relationships within the class. Related categories• ANATOMY AND PHYSIOLOGY• ZOOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |