All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement
Explanation Phylum Chordata includes animals that possess a notochord during some point in their life cycle. The phylum is further divided into 3 subphyla: Urochordata, Cephalochordata and Vertebrata. Urochordates shows the presence of notochord only in the tail region that later disappears during the adult stage. Whereas, in Cephalochordata, the notochord extends from head to tail region and persists throughout the life cycle. Animals belonging to subphyla Vertebrata possesses a notochord only during the embryonic period which is later replaced by a cartilaginous or bony vertebral column in adults. Thus, all vertebrates are chordates but all chordates are not vertebrates. Final Answer The characteristic feature of phylum Chordata is the presence of a notochord. Chordates possess a notochord during some point of their life cycle where some members show the presence of notochord throughout the life cycle. Whereas, the members of sub-phyla Vertebrata within the phylum Chordata possess a notochord only during the larval stage which is later during the adult stage replaced by a cartilaginous or bony vertebral column.
