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Line 1: − + − − They are a subphylum of [[chordates]].+ + + + + + + + + + + + + + + + + + + + − <references/>
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'''Vertebrates''' are defined as [[animal]]s that possess a [[spine|backbone]].<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia
'''Vertebrates''' are defined as [[animal]]s that possess a [[spine|backbone]].<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia Educational Ministries, Inc. 1998</ref> They are a subphylum of [[chordates]].
Educational Ministries, Inc. 1998</ref>
Vertebrates include [[fish]]es, [[reptile]]s, [[amphibian]]s, [[bird]]s, and [[mammal]]s, all having a vertebral column, or a chain of bony elements ([[vertebrae]]) that run along the dorsal surface from head to tail and form the main skeletal axis of the body. The vertebral column surrounds and more or less replaces the [[notochord]] as the chief "stiffener" of the body in locomotion. Some characteristics shared by most or all vertebrates (in addition to those traits shared among all [[Chordata|chordates]]) include the following (after Hickman, 1994):
*A skin or membrane of two divisions, including an outer [[epidermis]] and an inner [[dermis]]
*A skin or membrane often modified to produce hair, scales, feathers, glands, horn, etc.
*Replacement of notochord by a vertebral column more or less complete, depending on group
*A bony or [[Cartilage|cartilaginous]] [[endoskeleton]] consisting of [[cranium]], [[visceral arch]]es, limb girdles, and two pairs of appendages
*A muscular, perforated [[pharynx]] - this structure is the site of [[gill]]s in fishes but is much reduced in adult land-dwelling forms, although it is extremely important in [[embryo]]nic development of all vertebrates
*Locomotion provided by muscles attached to endoskeleton
*A igestive system with large digestive glands, [[liver]], and [[pancreas]]
*A ventral [[heart]] with 2-4 chambers
*[[Blood]] with [[Erythrocyte|red blood cells]] containing [[hemoglobin]], and [[Leukocyte|white blood cells]]
* A well developed body cavity (''coelom'') containing visceral systems
*Paired [[kidney]s with ducts to drain waste to exterior
*Most vertebrates have two distinct sexes, each with paired [[gonad]]s, although there are some exceptions
*A general body plan consisting of head, trunk, two pairs of appendages, and postanal tail (but these structures are highly modified in many vertebrates and sometimes absent).<ref>Myers, P. 2001. "Vertebrata" [http://animaldiversity.ummz.umich.edu/site/accounts/information/Vertebrata.html Animal Diversity Web] Accessed June 20, 2007</ref>
==See also==
*[[Scientific Classification]]
==References==
==References==
<references/>
[[Category:Biology]]
[[Category:Biology]]