Question

Give scientific reason

All vertebrates are chordates but all chordates are not vertebrates.

Answer 1

The members of Vertebrata possess notochord during embryonic development. Thus, all vertebrates are chordates. However, the notochord gets replaced by a cartilaginous or bony vertebral column in the adult. Thus, all chordates are not vertebrates.

Answer 2

The pharyngeal gill slits and notochord are the defining characteristics of the phylum Chordata. The notochord is only present in the larval stages of Urochordata and is missing in the adult stages. The notochord remains present throughout life in Cephalochordata. However, when we look at vertebrates, the notochord is eventually replaced by a bony or cartilaginous vertebral column in adulthood. Only in the embryos of vertebrate animals is the notochord present. As a result, all vertebrates are chordates but all chordates are not vertebrates.