I. Phylum Chordata A. Basic Chordate Characteristics B. Pre - vertebrate subphyla 1.
Chordates are the phylum which contains the sub-phylum Vertebrata.
The vertebrates are a monophyletic taxon containing the common ancestor of all vertebrates and containing only vertebrate descendants. The term invertebrate refers to a non-monophyletic group of animals who do not have backbones. Cephalochordates, included in the invertebrates, share their most recent common ancestor with the vertebrates. Therefore, this violates the rule of including in a monophyletic taxon the common ancestor and all of the descendants. You need to know the members and placement on the tree of Urochordata, Cephalochordata, the 7 classes of the subphylum Vertebrata, the homology which defines tetrapods and amniotes and the members of these groups A. Basic Chordate Characteristics in some stage of development.