What are the groups in the phylum Chordata?

Answer 1

All animals which have a spine, or backbone, are classified in the phylum Chordata. There are three subphylums in Chordata: the first two are invertebrates - Urochordata (tunicates e.g. marine filter feeders such as sea squirts), Cephalachordata (lancelets e.g. sessile burrowing marine animals), while the third is Vertebrata (vertebrates - all mammals, birds, fish, reptiles and amphibians).