Phylum Chordata MCQ - Practice Questions with Answers

The phylum chordata is characterized by the following:

Notochord: 

• The name ‘Chordata’ is based on the presence of notochord at some stage or throughout the life cycle
• It is a rod-like structure placed dorsally between the alimentary canal and nerve cord
• It is derived from the mesoderm
• In vertebrates, it is present during the embryonic development
• It is then replaced by the vertebral column (spine) in the postnatal stage

Dorsal Hollow Nerve Cord: 

• It is placed dorsally to the notochord 
• It is hollow rod and is derived from the ectoderm
• It develops into the brain and spinal cord and forms the central nervous system

Pharyngeal Gill Slits: 

• These are the openings present in the pharynx. 
• They allow the entry and exit of water in aquatic animals. 
• In vertebrate fishes, these develop into gills. In tetrapods, these are modified into tonsils and components of ears. 

Post-anal Tail: 

• It is the posterior elongation of the body that goes beyond the anus. 
• It consists of skeletal elements and muscles. 
• It helps in locomotion in fishes and in balancing in terrestrial vertebrates. 
• It is reduced and non-functional in man.