Phylum Chordata

1.	Phylum Chordata
Answer» All chordates are characterized by four features at different stages of their life:\tNotochord– It is a longitudinal, cartilaginous rod running between the nerve cord and the digestive track. It acts as a support for the nerve cord. In vertebrates, it is replaced by vertebral column after the embryonic stage.\tDorsal nerve cord–It is a bundle of nerves which runs along the “back” and splits into the brain and the spinal cord\tPharyngeal slits–They are the openings which allow the entry of water through the mouth without entering the digestive system i.e., they connect mouth and throat.\tPostanal tail–It is an extension of the body to the ****. In chordates, the tail is composed of skeletal muscles which help in locomotion in fish-like species.\xa0Other features of chordates include:\tBilaterally symmetrical, triploblastic, coelomic and segmented body.\tThe body design is complex and well-differentiated.\tThe body has organ system level of organization.

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