Question

Give scientific reasons.

All vertebrates are chordates but all chordates are not vertebrates.

Answer 1

1. All chordates possess a notochord in some period of their development.
2. All vertebrates also have a notochord during embryonic life, which is later replaced by the vertebral column.
3. But some chordates like Urochordata and Cephalochordata do not possess a vertebral column, and hence they are not vertebrates.

Therefore, all vertebrates are chordates but all chordates are not vertebrates.