Domain-Eukarya  

U. Maritimus is classified under the eukaryotic domain because it is a multi-cellular organism.  The cells that make up this organism contain a large variety of organelles.  Each cell is programmed to perform a specific task.  All of the cells communicate and work together to carry out daily activity.

Kingdom-Animalia

There are several distinct characteristics which place the polar bear in the animal kingdom.  Polar bears, like all other animals are eukaryotic, multi-cellular organisms.  They are heterotrophic, meaning that they get their food and energy from consuming other organisms.  Animals also lack cell walls and are motile. 

Phylum-Chordata

Polar bears are placed in the phylum chordata because they, like all other chordates, develop a notochord or "back-string" during the early stages of embryonic development. The notochord is a rod-like structure, composed of connective tissue (Gotch, 26).  Furthermore, all chordates have a dorsal tubular nerve chord, pharyngeal pouches, an endostyle and a postanal tail.  The dorsal nerve chord is derived from the ectoderm; whereas, the notochord is derived from the endoderm.  The endostyle secretes mucus and proteins which are rich in iodine.  In addition, chordates are bilaterally symmetrical, meaning that they face the environment in only one direction.  Polar bears have an increased complexity as well as an enhanced nervous system.

Subphylum-Vertebrata

U. Maritimus is one of 43,000 species included in the subphylum vertebrata (Gotch, 27).  All vertebrates share a unique set of joints located laterally down the back; these joints are commonly known as vertebrate.  Aside from the cartilaginous fish, all mammals, reptiles, birds and amphibians, use a  notochord for support during early development.  However, the notochord is replaced by a bony spinal column.  This structure is made up of a number of vertebrates which are fused together and connected to the remaining endoskeleton.

Class-Mammalia

The polar bear belongs in the class mammalia for 4  specific reasons; 1) it has true hair and 2) the polar bear uses the mammary gland to produce milk for their young 3) polar bears have several different glands 4) they undergo viviparity rather than oviparity-meaning that mother polar bears retain the developing embryo inside until it is fully developed

Subclass-Eutheria

Mammals included in this subclass are known as the "typical" or "well-made" animals.  This subclass separates mammals by looking at the how advanced their young are at the time of birth and the amount of parental care their young will need after birth.   Organisms that are placed in this subclass give birth to young that have reached the advanced state of development.  However, these mammals are unable to care for themselves after birth and are dependant on their mother.  The presence of a placenta is also a key characteristic among mammals of the Eutheria subclass (Gotch, 460)

Order-Carnivora

The order carnivora is one of the 19 orders within the class mammalia.  The carnivores consist of lions, dogs, weasels, and their kin (Gotch, 33).  Organisms within the order carnivora eat meat as their primary food source.

Family-Ursidae

All animals under the family ursidae are mammals and primarily consume meat.  Some common characteristics of bears under the family ursidae include: short tail, an elongated body, great ability to hear, good sense of smell and powerful claws used for predation.

Genus-Ursus

The genus ursus incldes all the bears most cosley related to the polar bear.  Those bears included in the genus ursus include U. Thibetanus, U. Americanus, U. Malayanus, U. Maritimus, and U. Arctos

Species-Ursus Maritimus  

Ursus Maritimus is one of the three species within the genus Ursus.  The polar bear is known for living among the Arctic pack ice (Gotch, 588).