Characteristics of Phylum Chordata




Characteristics of Phylum Chordata

  1. (Noton; back and chorda; cord).
  2. Kingdom: Animalia
  3. Presence of a notochord
  4. They are backboned animals (vertebrates),
  5. Most of the living chordates are familiar vertebrate animals.
  6. Presence of dorsal hollow nerve cord
  7. Blood vascular system: Present, closed type
  8. Ventral heart, hepatic portal system and RBC are present.
  9. Germ layer: Triploblastic.
  10. Symmetry: bilateral symmetry body.
  11. Coelom: Present. Well developed
  12. Presence of gill (pharyngeal) slits
  13. Presence of post anal tail

 

Phylum Chordata is divided into four sub-phylum:

  1. Hemichordata,
  2. Urochordata,
  3. Cephalochordata
  4. vertebrata or Craniata

 

1. Sub-Phylum: Hemichordata

  • (hemi: half; chorde: cord)
  • Habitat: exclusively marine
  • Notochord present only in anterior region
  • Notochord is also known as Buccal diverticulum
  • Body is soft worm like
  • Body is divided into Probosis, collar and trunk
  • Sexes are separate
  • Fertilization: external
  • Examples: Balanoglossus, Cephalodiscus, Atubaria

 

2. Sub-phylum: Urochordata

  • ( uros: tail; chorde: cord)
  • Habitat: marine
  • Notochord present only in tail region of tadpole larvae
  • Adult lack tail and organ for locomotion
  • Sex: Hermaphrodite
  • Fertilization: Cross and external
  • Development: indirect
  • Examples: Hermania, Salpa, Doliolum

 

3. Sub-phylum: Cephalochordate

  • (kephalo: head; chorde: cord)
  • Notochord present from head to tail and persist throughout life
  • Pharynx is well developed with numerous gill slits
  • Coelom present
  • Body resemble small fish like
  • Circulatory system well developed
  • Sexes: separate
  • Fertilization: external
  • Development: indirect
  • Examples; Amphioxus, Asymmetron

 

4. Subphylum: Vertebrata

  • (vertebra: backbone)
  • Also known as craniate)
  • Habitat: Aquatic as well as terrestrial
  • Notochord is replaced by vertebrae or backbone
  • Germ layer: triploblastic
  • Symmetry: bilateral
  • Body divided into head, trunk and tail
  • Excretion: a pair of kidney
  • Circulation system: closed type
  • Blood pigment present
  • Sexes: separate
  • Fertilization; internal or external

The vertebrata is sub-divided into two divisions:

i. Agnatha (Lack jaw) and

ii. Gnathostomata (Possess jaw).

  • The Gnathostomata are further divided into six classes:
  • Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves and Mammalia.

Characteristics of Phylum Chordata