Animal Kingdom Question 47
47. Which of the following statements are true for the phylum-Chordata?
(i) In Urochordata notochord extends from head to tail and it is present throughout their life. (ii) In Vertebrata notochord is present during the embryonic period only. (iii) Central nervous system is dorsal and hollow. (iv) Chordata is divided into 3 subphyla: Hemichordata, Tunicata and Cephalochordata.
(a) (iii) and (i)
(c) (ii) and (iii)
(b) (i) and (ii)
(d) (i) and (iii)
Show Answer
Answer : c
Hints & Solutions
(c) In vertebrata, notochord is present during embryonic period only as it is replaced by vertebral column. In chordates, central nervous system is dorsal and hollow. The notochord derives during gastrulation (infolding of the blastula, or early embryo) from cells that migrate anteriorly in the midline between the hypoblast and the epiblast (inner and outer layers of the blastula). These cells coalesce immediately beneath the developing central nervous system.
