Question

Vertebrates belong to a group of chordates in which the notochord is modified into vertebral column. Which one of the following statement is true?

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

Answer 1

The correct option is A All vertebrates are chordates but all chordates are not vertebrates.

All vertebrates are chordates but all chordates are not vertebrates.

The characteristic features of the phylum Chordata include the presence of a notochord and paired pharyngeal gill slits. In sub-phylum Vertebrata, the notochord present in the embryo gets replaced by a cartilaginous or bony vertebral column in adults. But in cephalochordates, notochord persists throughout life as such and in urochordates, the notochord is present only in larval stages and absent in adults. Thus, it can be said that 'All vertebrates are chordates but all chordates are not vertebrates'.