Question

Why are Urochordata and Cephalochordata called Protochordata?

Answer 1

Protochordate:

1. Phylum Chordata is divided into three subphyla: Urochordata or Tunicata, Cephalochordata, and Vertebrata.
2. Urochordata and Cephalochordata are collectively called protochordate.
3. Characteristics feature of Phylum Chordata is the presence of notochord.
4. In the sub-phylum Urochordata, the notochord is present only in the larval tail.
5. In the sub-phylum Cephalochordata, the notochord is present in head to toe region and persistent throughout life.
6. In the sub-phylum Vertebrata, the notochord is changed into the bony, hollow vertebral column.
7. Hence, the Urochordata and Cephalochordata are called protochordate because they are the primitive form of chordates.