Why are are humans in Phylum Chordata?

Answer 1

To answer the question in the simplest way, humans have a backbone.

However, there is more to it than that, especially given that there are two invertebrate chordate groups - Urochordata (tunicates) and Cephalachordata (lancelets) - whose backbone is not in the form of actual vertebrae.

As Chordates (or members of the phylum Chordata), human beings share the following characteristics:

dorsal nerve cord which is a bundle of nerve fibres which runs down the back. It connects the brain with the lateral muscles and other organs.

notochordwhich is a cartilaginous rod running underneath, and supporting, the nerve cord - in the case of humans, a spine.

post-anal tail - an extension of the body past the anal opening. (This feature is not always present in some adult Chordates such as frogs and humans)

Pharyngeal pouches - Chordates, at some stage of their life, have pharyngeal grooves and pouches that develop into other essential parts of their anatomy.

Answer 2

Humans are in Phylum Chordata because they possess a notochord, a dorsal nerve cord, pharyngeal slits, and a post-anal tail at some point during their development. These characteristics are defining traits of the phylum Chordata, to which humans belong.