What does the chordata classification encompass?

The chordata classification encompasses vertebrate animals, which includes a wide range of organisms such as mammals, birds, reptiles, amphibians, and fish. All members of the phylum Chordata share specific characteristics at some stage of their development, such as a notochord (a flexible rod-like structure), a dorsal nerve cord, pharyngeal slits, and a post-anal tail. Humans, being mammals, are included within this diverse classification.

While amphibians are part of the chordates, the classification itself is much broader and includes many more groups, so focusing solely on amphibians would not represent the whole classification. Invertebrates, which do not have a backbone, are not included in the chordata phylum, as this group is specifically defined by the presence of neural and skeletal structures. Prokaryotic organisms, such as bacteria and archaea, are fundamentally different from chordates, belonging to distinct domains of life that lack a nucleus and complex cellular structures. Thus, the classification of chordata is indeed centered around vertebrate animals, making this the accurate choice.