6,786
edits
Changes
Jump to navigation
Jump to search
Line 1:
Line 1: − '''Vertebrates''', which include [[fish]]es, [[reptile]]s, [[amphibian]]s, [[bird]]s, and [[mammal]]s, all share 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/>
Redirecting to Vertebrate
#REDIRECT [[Vertebrate]]