Question

Presence of notochord, is the distinctive feature of which of the following Phylum?
1.  Annelida
2. Chordata
3. Echinodermata
4. Arthropoda

Answer 1

Correct Answer - Option 2 : Chordata

The correct answer is Chordata.

• Animals belonging to the phylum Chordata are basically characterized by the presence of a notochord, a dorsal hollow nerve cord, and paired pharyngeal gill slits. 
• These are bilaterally symmetrical, triploblastic, coelomate with the organ-system level of organization.
• The notochord is a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and in the adult stage. It is located between the digestive tube and the nerve cord and provides support.
• The blood vascular system is present and it is closed type.
• They possess a post-anal tail and a closed circulatory system.
• Common Examples are- Branchiostoma, Ascidia, Lizards. 

Phylum	Distinctive Features	Examples
Porifera	Body with pores and canals in walls	Sycon (Scypha), Spongilla (Freshwater sponge), and Euspongia (Bath sponge).
Coelenterata	Cnidoblasts present	Aurelia (jellyfish), Physalia (Portuguese man-of-war), Adams (Sea anemone), Pennatula (Sea-pen), Gorgonia (Sea-fan), and Meandrina (Brain coral).
Ctenophora	Comb plates for locomotion	Pleurobrachia and Ctenoplana.
Platyhelminthes	Flat body, suckers	Tape warm and liver fluke
Aschelminthes	Often worm-shaped, elongated	Female roundworm
Annelida	Body segmentation like rings	Nereis, Hirudinaria
Arthropoda	The exoskeleton of the cuticle jointed appendages	Prawns, butterflies, houseflies, spiders, scorpions, and crabs
Mollusca	The external skeleton of the shell usually present	Mussels, scallops, oysters, periwinkles, whelks, squid, clams, snails, and octopus
Echinodermata	Water vascular system, radial symmetry	Starfish, Sea urchin, Sea lily, Sea cucumber, Brittle star.
Hemichordata	Worm-like with proboscis, collar, and trunk	Balanoglossus, Saccoglossus, Rhabdopleura, Atubaria, Dendrograptus.
Chordata	The notochord, dorsal hollow nerve cord, gill slits with limbs or fins	Urochordata – Ascidia, Salpa, Doliolum; Cephalochordata – Amphioxus or Lancelet.