Phylum Chordata

Topic Content:

Characteristics of Phylum Chordata: 

1. All chordates including the vertebrates have a flexible rod-like structure, the notochord (a simple pre-backbone structure), at some stage of their development. 

2. They have a tubular dorsal nerve chord . This a bundle of nerves running along the “back” that splits into the brain and the spinal cord. It is hollow and lies dorsal to the notochord.

3. They have pharyngeal gill slits at some stage of their life histories. They are openings that allow the entry of water through the mouth without entering the digestive system. In many aquatic forms, they are lined with vascular lamellae, which form gills for respiration.

4. Post-anal tail: It is an extension of the body that runs past the anal opening.

5. The body has an organ system level of organisation.

6. They are true coelomates .

7. Bilaterally symmetrical, triploblastic, coelomic, and segmented body.

8. A well-differentiated and complex body.

Note: The notochord is the defining structure of the chordates, and has essential roles in vertebrate