4 Fundamental Character of Chordata | Free Biology Notes

After reading this article you will learn about fundamental character of chordata

Fundamental Character of Chordata

1. Presence of notochord

• In Embryonic stage of chordate animals there is a solid stick/rod like structure called notochord
• It is present just below nerve cord and above alimentary canal
• Notochord is extended from anterior to posterior end of body at dorsal surface
• It is mesodermal in origin
• In protochordate, it persists throughout life
• In vertebrates, it is replaced by backbone / vertebral column in adults

2. Presence of nerve cord

• In chordates CNS is situated at dorsal surface of body
• Nerve cord is single, hollow and tubular
• Nerve cord is present below the body wall and just above notochord
• Nerve cord is ectodermal in origin

3. Presence of pharyngeal gill slits

• In each chordate animal there are paired lateral gill slits in wall of pharynx for respiration in any stage of life span
• In aquatic chordates and lower chordates pharyngeal gill slits are present throughout their life span for respiration
• In terrestrial chordates, gill slits are found only in embryonic stages and are absent in adults as they have lungs

4. Presence of post anal tail

• In chordates tail if present is the post anal part of body
• Tail is reduced or absent in many adult chordates