Question

Bipinnaria is the larval stage of 
1. Coelenterata
2. Mollusca
3. Echinodermata
4. Hemichordata

Answer 1

Correct Answer - Option 3 : Echinodermata

Concept-

• The larva is a stage in the development of many animals, occurring after birth or hatching and before the adult form is reached. These immature, active forms are structurally different from the adults and are adapted to a different environment.
• There are different types of larvas like Tonaria larva, Muller's larva, Tadpole larva, etc.

Explanation:

Echinodermata:

• The five classes of existing echinoderms are these:

1. Crinoidea - Body form is plant-like i.e. fixed. Larva: Doliolaria
2. Asteroidea - Body form is flat & star-like. Larva: Bipinnaria, dipleura 
3. Ophiuroidea - Body form is flat & star-like. Larva: Ophiopluteus
4. Echinoidea - Body form is globular & disc-like. Larva: Echinopleutus 
5. Holothuroidea - Body form is long & cylindrical. Larva: Auricularia

Thereby, Bipinnaria is the larval stage of ''Echinodermata''

• Other important features of phylum Echinodermata are:

1. They have an endoskeleton made up of calcareous ossicles.
2. All are marine with an organ-system level of organization.
3. The adult echinoderms are radially symmetrical but larvae are bilaterally symmetrical.
4. They are triploblastic and coelomate animals.
5. The digestive system is complete with a mouth on the lower (ventral) side and anus on the upper (dorsal) side
6. Examples: Asterias (Starfish), Echinus (Sea urchin), Antedon (Sea lily), Cucumaria (Sea cucumber), and Ophiura (Brittle star)