EVERYDAY SCIENCE

Detailed explanation-1: -Notochord. The chordates are named for the notochord: a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and also in the adult stage of some chordate species. It is located between the digestive tube and the nerve cord, providing skeletal support through the length of the body.

Detailed explanation-2: -The notochord is a stiff but flexible rod of cells and connective tissue (from the Greek root words noto meaning back and chord meaning string) that gives the phylum its name, Chordata. In some chordates the notochord is a major support structure (Fig. 3.98).

Detailed explanation-3: -The notochord is the defining structure of the chordates, and has essential roles in vertebrate development. It serves as a source of midline signals that pattern surrounding tissues and as a major skeletal element of the developing embryo.

Detailed explanation-4: -All animals that possess a notochord are called chordates. Vertebrata is a sub-phylum under Phylum Chordata and are hence, “vertebrate” is not synonymous to “chordate". Vertebrates possess notochord during the embryonic period.

Detailed explanation-5: -They have well developed vertebral column forming the main axis of their internal skeleton, which may be of bones or cartilage.