Zoology MCQs for NEET — Practice Questions with Answers

According to the NCERT text, the fundamental features of Phylum Chordata include a notochord, a dorsal hollow nerve cord, and paired pharyngeal gill slits. The central nervous system is dorsal, hollow, and single, not ventral, solid, and double. This latter description applies to non-chordates.

The NCERT states, 'Subphyla Urochordata and Cephalochordata are often referred to as protochordates and are exclusively marine.'

The NCERT explicitly states: 'In Urochordata, notochord is present only in larval tail, while in Cephalochordata, it extends from head to tail region and is persistent throughout their life.'

The NCERT lists 'Branchiostoma (Amphioxus or Lancelet)' as an example of Cephalochordata, while Ascidia, Salpa, and Doliolum are examples of Urochordata.

The NCERT text states: 'They possess a post anal tail and a closed circulatory system' referring to Chordates in general.

Table 4.1 in NCERT states: 'Chordates: Central nervous system is dorsal, hollow and single.' and 'Non-chordates: Central nervous system is ventral, solid and double.'

The NCERT states: 'The members of subphylum Vertebrata possess notochord during the embryonic period. The notochord is replaced by a cartilaginous or bony vertebral column in the adult.'

The NCERT explains this: 'Thus all vertebrates are chordates but all chordates are not vertebrates.' This is because subphyla Urochordata and Cephalochordata (protochordates) are chordates, but they do not develop a vertebral column from the notochord, which is a defining characteristic of vertebrates.

Examples of Urochordata given in NCERT are 'Ascidia, Salpa, Doliolum'. Branchiostoma/Amphioxus/Lancelet are Cephalochordates. Balanoglossus is a Hemichordate. Asterias/Ophiura are Echinoderms.

The NCERT states: 'Subphyla Urochordata and Cephalochordata are often referred to as protochordates and are exclusively marine.'