Phylum : Chordata

All the animals belonging to Phylum Chordata possess certain fundamental and unique characteristic features.

  • They possess a notochord (or chorda dorsalis) which persists as such throughout their life in some animals, or is replaced by a well developed vertebral column in some others.
  • They have a dorsal, hollow, tubular nerve cord (also known as spinal cord) above the notochord.
  • They possess paired pharyngeal gill slits in the embryonic stage. It either remains functional throughout the life or gets replaced by a pair of lungs.
  • There is also a post anal tail in the embryonic stage of all the members.

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Habitat: They are found in both terrestrial and aquatic habitats.

Body plan: They have organ-system level of organisation

Symmetry: Chordates are bilaterally symmetrical.

Germ layer: They are triploblastic and coelomate animals.

Classification

Phylum Chordata is divided into three subphyla.

  1. Urochordata or Tunicata
  2. Cephalochordata
  3. Vertebrata

Phylum Chordata

Subphylum

Vertebrata

Subphylum

Cephalochordata

Subphylum

Urochordata

Commonly known as Protochordates or Acrania.

They are exclusively marine.

  • Examples

Ascidia

Salpa

Doliolum

  • Examples

Branchiostoma

(Amphioxus or Lancelet).

  • Examples

Frog

Elephant

Whale

  • Notochord

Present only in the larval tail.

  • Notochord

Extends from head to tail and persists throughout life.

  • Notochord

Present in the embryonic period. It is replaced by Vertebral column in the adult.

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Vertebrates

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Branchiostoma

Ascidia

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Salpa