what is the fate of notochord in vertebrates
Notochord Notochords are thought to be advantageous (both in an evolutionary and developmental context) because they provide(d) rigid structure for muscle attachment, but were still flexible. In some chordates, it persists throughout life as the main structural support of the body, while in most vertebrates it becomes the nucleus pulposus of the intervertebral disc.[1] The notochord plays a key role in signaling and coordinating development. Embryos of vertebrates still form transient notochord structures today during the gastrulation phase of development. The notochord is found ventral to the neural tube.
Evidence of common descent Evidence for common descent comes from the existence of vestigial structures.[62] These rudimentary structures are often homologous to structures that correspond in related or ancestral species. A wide range of structures exist such as mutated and non-functioning genes, parts of a flower, muscles, organs, and even behaviors. This variety can be found across many different groups of species. In many cases they are degenerated or underdeveloped. The existence of vestigial organs can be explained in terms of changes in the environment or modes of life of the species. Those organs are typically functional in the ancestral species but are now either semi-functional, nonfunctional, or re-purposed.