Vert., Emporia State Univ. These notes are provided to help direct your study from the textbook . If you were to study only these notes, you would not learn enough to do well in the course. Basically, a vertebrate is a chordate with a cartilaginous or bony endoskeleton. Support provided by an elastic notochord Food is filtered from the water as it enters the mouth.
Food is trapped in mucus as the water passes over the cilia and through the pharyngeal slits.
The trapped food is then carried into the digestive system. Several authors have argued for the Urochordata to be the sister taxon for the Vertebrata. Early vertebrates possibly originated from a tunicate-like larva that became sexually mature without metamorphosis to the adult body plan through a process called paedomorphosis . Paedomorphosis is divided into two processes Neoteny , which is the retention of a few larval characteristics into the adult stage Progenesis , which is the development of sexually mature gonads in the larval stage. The structure of the tooth-like fossils and the impressions of conodont fossils indicates that these organisms were early vertebrates.