Phylum Chordata: Introduction to Phylum Chordata, Features of Chordates (For CBSE, ICSE, IAS, NET, NRA 2022)

Get unlimited access to the best preparation resource for UGC : Get detailed illustrated notes covering entire syllabus: point-by-point for high retention.

Introduction to Phylum Chordata

  • Phylum Chordata possess a bilaterally symmetrical body and presence of notochord is most distinguishing character that all animals belonging to this phylum.
  • It belongs to the Kingdom Animalia and includes all the vertebrates, i.e.. , animals with a backbone along with several invertebrates, i.e.. , organisms without a backbone.

Features of Chordates

Features of Chordates

Notochord

  • Its main function is to support the nerve cord.
  • The vertebral column replaces the notochord in vertebrate animals.
  • Notochord further consists of a longitudinal rod that is made of cartilage and runs between the nerve cord and the digestive tract.

Dorsal Nerve Cord

A bundle of nerve fiber which connects the brain to the muscles and other organs.

Post-Anal Tail

The tail has skeletal muscles in some chordates which help in locomotion.

Pharyngeal Slits

  • These are the openings connecting the mouth and the throat.
  • The entry of water through the mouth is allowed without entering the digestive system.
  • This is the third largest phylum in the subphylum Vertebrata.

Division of Phylum Chordata

Division of Phylum Chordata

Urochordata

  • It is also known as Tunicata because the body of an adult is enclosed within a tunic made up of cellulose like substance known as tunicin.
  • A dorsal ganglion in adults replaces the nerve cord present in larva.
  • The larva can move and undergoes metamorphosis.
  • For e. g. Ascidia, Salpa, Doliolum.

Cephalochordata

  • The tail is present throughout the life.
  • Progressive metamorphosis is shown.
  • The notochord is found throughout life.
  • For e. g. Lancelets possess the notochord and nerve cord throughout their life.

Vertebrata

  • These contain advanced chordates and have cranium around the brain.
  • A high degree of cephalization is observed.
  • They have a well-developed coelom (the principal body cavity in most animals) .
  • The alimentary canal is complete.
  • For e. g. in Humans.