Question

In some chordates, the notochord is modified as thevertebral column. Such animals are called vertebrates.Which one of the following statements make sense?

• A. All chordates are vertebrates but all vertebrates are not chordates
• B. All vertebrates are chordates and all chordates are vertebrates
• C. All vertebrates are chordates but all chordates are not vertebrates
• D. Chordates are not vertebrates and vertebrates are not chordates

Answer 1

Answer: (C)

The terms chordate and vertebrate are not synonymous. Chordates include all those animals which possess three peculiar features-dorsal tubular nerve cord, rod like notochord and pharyngeal gill slits. All these conspicuous features are too shared by vertebrates; but in most adult vertebrates the notochord is replaced with the backbone or vertebral column, which is the peculiar feature of vertebrates. All chordates except hag fishes convert their notochord into a vertebral column.