Question

Write the features of chordates.

Answer 1

The non-chordates and chordates are differentiated from each other based upon certain characteristics. Taxonomic classification of animals is done depending on certain characteristic features that differ from one group to the others.

Complete answer:
The Phylum Chordate under Kingdom Animalia possesses the following key characteristics that are not present in the Non- chordates:
-Notochord
-Nerve cord
-Pharyngeal gill slits
-Post- anal tail.
Notochord- A rod-like structure formed from the mesodermal germ layers and extends longitudinally in the body of chordates. In some animals, for example, Lamprey, notochords are found throughout the lifetime whereas in others it transforms to other structures with increasing age.
Nerve cord- A cord that is dorsally placed in a vertebrate body from where the important structures like the brain and parts of the spinal cord arise is known as nerve- cord.
Pharyngeal gill slits- In the thorax region, pharyngeal gill slits are present for the gaseous exchange. In certain animals, slits also function in removing food particles.
Post-anal tail- The posterior part of the chordate body gets extended to give rise to the post-anal tail. In humans and apes, such structures are only present during embryonic development. The post-anal tail is an extension of the spinal cord in the posterior end.

Note: Fishes, amphibians, reptiles, mammals, birds belong to phylum Chordata. Thus all chordates possess the above mentioned distinguishing features though in higher grade organisms some structures later disappear. The hemichordates with only the pharyngeal gill slits are the closest to chordates. They lack the other characteristics and thus are differentiated from the chordates.