Question

The feature that is not a characteristic of protochordata?
A. Presence of notochord
B. Bilateral symmetry and coelom
C. Jointed legs
D. Presence of closed circulatory system
E. Both C and D

Answer 1

Chordates are included in the phylum Chordata. These are vertebrates that possess a notochord, a dorsal nerve cord, post-anal tail or pharyngeal silk during their stage of development. Example: Fishes, reptiles, birds, and mammals.

Complete answer:
Presence of notochord at some stage of development is the characteristic feature of chordates. Protochordates are the most primitive or oldest chordates. It includes tunicates and cephalochords .
Chordates have a bilaterally symmetrical body with the presence of three germinal layers. They have a segmented body with a well-developed and complete digestive tract.The feature that is not a characteristic of protochordata is jointed legs and presence of closed circulatory system so option (E) both (C) and (D) are correct.

Jointed legs are found in arthropods and surely it is not found in protochordata. These are generally marine animals. Example: Balanoglossus. The phylum chordata is divided into three sub phylum namely.
(a) Cephalochordata: These are borrowed in habitat and are filter feeders. They are small, vaguely fish shaped animals. They look brainy.
(b) Urochordata: They are also known as turnicata. They exist in two forms ‘sea squirts’ and ‘slaps’. These are soft-bodied filter feeders. They form colonies and even exist in solitary form. They feed on plankton.
(c) Craniata: These organisms have distinct skulls. They are vertebrates in which the notochord is replaced by the vertebral column.

Therefore, from the above explanation the correct option is (E) Both C and D.

Note: Chordates are named due to the presence of chordate or rod like structure called notochord is located between the digestive tube and nerve cord. It provides support and helps in flexible location for attachment of axial muscle.