Question

"All vertebrates are chordates but all chordates are not vertebrates". Justify the statement.

Answer 1

• The characteristic features of the phylum Chordata include the presence of a notochord and paired pharyngeal gill slits.
• Chordates include urochordates, cephalochordates, and vertebrates.
  
• In subphylum Vertebrata, the notochord present in embryos 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.