Question

“All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement.

Answer 1

Hint: As we know that chordates are characterized by the presence of notochord in this should persist through the whole life span.

Complete Answer:
- In the given statement we need to justify the statements with proper reasoning.
- As we know that all vertebrates have the presence of notochord during their embryonic stages but the adults have a replacement of notochord with the bony or cartilaginous vertebral column.
- This is also a well known fact that the vertebrates have a characteristic feature of having a notochord with the presence of paired pharyngeal gill slits as well as the presence of an post-anal tail.
- In the phylum chordata there is the presence of sub phylum in it such as vertebrates, hemichordates, cephalochordates, etc which clearly tells that the all vertebrates are chordates but all chordates are not vertebrates as other subphyla are also present.
- Chordates do not have the presence of vertebral column whereas the vertebrates have one present in them.

Note: It is noted that notochord presence is the specialized feature of the chordates which tends to change in some subphylums and stays the same in other sub phylums. Chordates are all the members present in it whether urochordates, cephalochordates or vertebrates but vertebrates are only the members present in this subphylum.