This subphylum includes the vertebrates. This includes fish, reptiles, birds, and mammals. All of those animals have one thing in common, they all share a vertebral clumn that run from head to tail of the body. The vertebral column surrounds and replaces the notochord as the stiffener of the body. The majority of all vertebrates share these characteristics. They have two layers of skin an outer and inner epidermis. They have a bony endoskeleton that consists of a cranium, limb girdles and two pairs of appendages. Movement is provided by muscles that are attached to the endoskeleton. They have a digestive system with glands, a liver, and a pancreas. A ventral heart with two to four chambers, this means they have a closed circulatory system.
Vertebrates also have a fully developed body cavity which is coelom and has visceral systems. The excritory system has two kidneys that drain waste to the exterior. They have a complete nervous system wtih nerves running throughout the body. They have two sexes each with their own pair of gonads. Finally, each body plan is generally the same and consists of a head, trunk, two pairs of appendages, and sometimes a tail, however, some of these structures are often time absent.
This subphylum also has eight classes: Myxini, Cephalasphidomorphi, Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, and Mammalia. To view these links simply click on the word.
Polar Bear (Ursus Maritimus)
Myers, P. 2001. "Vertebrata" (On-line), Animal Diversity Web. Accessed March 01, 2011 http://animaldiversity.ummz.umich.edu/site/accounts/information/Vertebrata.html.
