How do gastropods differ from bivalves?
1 Answer
Sep 6, 2014
Molluscs possess a soft body, which is divided in visceral mass and foot. Visceral mass remains covered by special skin called mantle, which is capable of secreting a shell.
Gastropods and Bivalve belong to the same phylum, Mollusc, but different classes due to very striking differences.
Explanation:
Class: Gastropod
- Symmetry: The gastropods are asymmetrical because of an embryonic event, which is called torsion: this could be followed by coiling; visceral mass is covered by a single piece, usually coiled, shell.
- Habitat: They are either aquatic or terrestrial (in damp environment).
- Respiration: The aquatic gastropods have gills while in terrestrial gastropods the mantle cavity is converted into lungs.
- Example: garden snail and slug (shell lost).
Class: Bivalve
- Symmetry: These animals are bilaterally symmetrical. Their body is laterally compressed and is enclosed in two pieces of shells.
- Habitat: Bivalves are aquatic animals.
- Respiration: The process of respiration is carried out by plate-like gills.
- Example: marine mussel and oyster