Explain the distinct features of Phylum Chordata.

Explanation

All chordates possess three fundamental distinct features at some stage of their life cycle.
2. Presence of elongated rod like notochord below the nerve cord and above the alimentary canal.
3. It serves as a primitive internal skeleton. It may persist throughout life in lancelets and lampreys.
4. In adult vertebrates, it may be partially or completely replaced by backbone or vertebral column.
5. A dorsal hollow or tubular fluid filled nerve cord lies above the notochord and below the dorsal body wall. It serves to integrate and co-ordinate the body functions.
6. In higher chordates, the anterior end of the nerve cord gets enlarged to form the brain and the posterior part becomes the spinal cord, protected inside the vertebral column.
A dorsal hollow or tubular fluid filled nerve cord lies above the notochord and below the dorsal body wall.
It serves to integrate and co-ordinate the body functions. In higher chordates, the anterior end of the nerve cord gets enlarged to form the brain and the posterior part becomes the spinal cord, protected inside the vertebral column triploblastic, coelomates with organ system level of organisation, they possess post anal tail, closed circulatory system with a ventral myogenic heart except in Amphioxus.