formation of notochord is a topic of which lesson in zoology
Answers
Answer:The notochord (axial mesoderm, notochordal process) is the defining structure forming in all chordate embryos (taxonomic rank: phylum Chordata). It is an early forming midline structure in the trilaminar embryo mesoderm layer initially ventral to the ectoderm, then neural plate and finally neural tube.
Explanation:
Answer:
Most schoolchildren know what a spine is and could even point it out on a diagram. Even if it was a diagram of a non-human animal like a dog, the spine is pretty easy to figure out. 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. In fact, it is the defining feature of that particular phylum. Notochords, and furthermore backbones, are what separate us from the more primitive living creatures that we encounter.
The notochord is oriented head to tail and is found between the digestive tube and the nerve cord. Since it is composed of stiffer tissue, it allows for skeletal support of the organism. In certain chordates, like the lamprey and the sturgeon, the notochord remains there for life. In vertebrates, such as humans, a more complex backbone appears with only portions of the notochord remaining. As our backbone fully forms, the discs in our back is where the pieces of notochord are found as a sort of gelatinous material.