Science, Tech, Math › Animals & Nature The Deifinition and Origin of a Notochord Notochords are often described as a backbone for chordates Share Flipboard Email Print Sirachai Arunrugstichai / Getty Images Animals & Nature Marine Life Key Terms Marine Life Profiles Marine Habitat Profiles Sharks Amphibians Birds Habitat Profiles Mammals Reptiles Insects Forestry Dinosaurs Evolution View More By Jennifer Kennedy Marine Science Expert M.S., Resource Administration and Management, University of New Hampshire B.S., Natural Resources, Cornell University Jennifer Kennedy, M.S., is an environmental educator specializing in marine life. She serves as the executive director of the Blue Ocean Society for Marine Conservation. our editorial process Jennifer Kennedy Updated September 15, 2017 A notochord is often described as a primitive backbone. The word notochord comes from the Greek words notos (back) and chorde (cord). It is a rigid, cartilaginous rod that is present at some stage of development in all chordates. Some organisms, like African lungfish, tadpoles, and sturgeon, retain a post-embryonic notochord. The notochord is formed during gastrulation (an early phase in the development of most animals) and lies along the axis from the head to the tail. Notochord research has played an important role in scientists' understanding the development of animals' central nervous system. Notochord Structure Notochords provide a rigid, yet flexible structure that enables muscle attachment, which is believed to be advantageous both for individual development and evolution. It is made from a material that is similar to cartilage, the tissue you find at the tip of your nose and a shark's cartilaginous skeleton. Notochord Development The development of the notochord is known as notogenesis. In some chordates, the notochord is present as a rod of cells that lies beneath and parallel the nerve cord, giving it support. Some animals, like tunicates or sea squirts, have a notochord during their larval stage. In vertebrates, the notochord is typically present only in the embryo stage.