Explain why the notochord is an evolutionary advancement Wha

Explain why the notochord is an evolutionary advancement. (What is a notochord and why is it adaptive?) Annelid worms such as the earthworm are able to exchange gases using their skin. Why then do we see the development of complex gills in animals such the clam and amphibian? (Why are gills adaptive?) Describe the evolutionary trends regarding jaws and internal support (i.e. skeleton) for the following three groups of fish: hagfish, lamprey, and the other fishes (e.g. bony fish and shark). Why might the evolutionary development of vertebrae and jaws be adaptive? Explain how the skin of reptiles adaptive for terrestrial existence. (Is your skin also adaptive for a terrestrial existence?) Amphibians lack an amniotic egg. In what way does this limit them?

Solution

Notochord is a solid,flexible, rod like sreucture present on the dorsal side of the body at some stage of life of certain group of animals called chordates. It is also called chorda dorsalis.

Notochords are thought to be advantageous in an evolutionary and developmental context, because it provides rigid structure for muscle attachment, but is still flexible. In some chordates, it persists throughout life as the main axial support of the body, while in most tetrapods it is replaced partly or fully by vertebral column. The notochord plays a key role in signaling and coordinating development.