All Chordates share four key features, which includes; a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post tail.
The notochord provides skeletal support, gives the phylum its name, and develops into the vertebral column in vertebrates.
The dorsal hollow nerve cord develops into the central nervous system: the brain and spine.
Pharyngeal slits are openings in the pharynx that develop into gill arches in bony fish and into the jaw and inner ear in terrestrial animals.
The post tail is a skeletal extension of the posterior end of the body, being absent in humans and apes, although present during embryonic development.
