Wiley, Edward O., III Natural History Museum, University of Kansas, Lawrence, Kansas.
Last reviewed:August 2016
Show previous versions
- Lampreys and fossil jawless fishes
- Jawed vertebrates
- Links to Primary Literature
- Additional Readings
The major subphylum of the phylum Chordata, including all animals with backbones, from fish to humans. The subphylum Vertebrata constitutes the largest natural group (clade, monophyletic group) of chordate animals (phylum Chordata). As is observed in all chordates, vertebrates have a notochord, but it is largely replaced by vertebrae (initially neural arches that surround the nerve cord) during development. Together with the living hagfishes (order Myxiniformes) and many fossil groups, vertebrates are members of the Craniata. One major theme of craniate evolution is the increasing elaboration of the brain, its cranial nerves, and many sensory organs, such as the organs of smell (olfactory), hearing (inner ear), and feel (sensory organs of the lateral line system). A unique innovation is the evolution of neural crest cells, that is, cells that begin development along the neural crest of the embryo and that then migrate to many parts of the body, giving rise to or contributing to the formation of such structures as the cranium and the branchial arches (a remnant of which remains in humans as parts of the larynx). Vertebrates have a long fossil history. Earliest fossils of jawless vertebrates are known from the late Cambrian (490 million years before the present). Jawed vertebrate fossils are known from the Ordovician (450 million years before the present), and this group began to predominate in the Devonian (about 360 million years before the present). See also: Animal evolution; Chordata; Fossil; Myxiniformes; Nervous system (vertebrate); Neural crest; Vertebra; Vertebrate brain (evolution)
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information