deoxyribonucleic acid, desoxyribonucleic acid, DNA(noun) (biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix; associated with the transmission of genetic information.
But even adults don't often know what a notochord is. A notochord is a primitive beginning to the backbone. It appears in embryos as a small flexible rod made from cells from the mesoderm, which is one of the three layers of cells of embryos. Notochords are only found in the phylum chordata, a group of animals that includes humans.
Classes Found In The Phylum-Chordata All chordates have a number of structures in common: A notochord (noto = the back; chord = string) is present in all embryos, and may be present or absent/reduced in adults.This is the structure for which the phylum was named.The notochord is a rod-like structure that forms the supporting axis of the embryo and gives birth to the vertebral column in vertebrates. Chordates are sometimes referred to as â vertebrates â because most possess a backbone with vertebrae.his is the structure for which the phylum was named. The notochord is a rod-like structure that forms the supporting axis of the embryo and gives birth to the vertebral column in vertebrates. Chordates are sometimes referred to as â vertebrates â because most possess a backbone with vertebrae.