One common characteristic of members of the phylum chordata is the notochord. The notochord is a rod made of cartilage that supports the nerve chord and runs beneath it.
Another common characteristic is pharyngeal slits, which are openings in the neck of the animal that connect the neck to the throat. In some members of the chordata phylum, these slits develop into gills.
Another common characteristic is a nerve cord that runs along the back of the animal. Chordates also have an endostyle, which is a furrow in a wall of the pharynx. This furrow develops in filter feeders and stores iodine.
The last common characteristic of a chordate is a tail that extends past the anus.
Humans are members of the chordata phylum, and these characteristics apply to them as well. The pharyngeal slits, endostyle and tail can be found at some point in the development of the human embryo, but they disappear before the baby is born.
Chordata is an extremely varied phyllum and includes not only mammals but fish, reptiles, amphibians and birds. Subdivisions of chordata are the craniata, tunicates and lancelets. Craniates have skull bones but lack vertebrae and are thought to be the ancestors of chordates. Tunicates have chordate characteristics as larvae, and lancelets are brainless, fish-like filter feeders.