Bivalvia – Marine molluscs
Widely distributed class of invertebrates found in aquatic habitats throughout the world
The defining feature of bivalves is their hinged, two-part shells. These shells provide protection and serve as a defense mechanism against predators. The shells can vary in shape, size, and ornamentation, reflecting the diverse adaptations of different species. They are also efficient filter feeders, extracting microscopic algae and particles from the water. They use specialized structures called gills to filter and extract nutrients, playing a crucial role in maintaining water quality and nutrient cycling in aquatic ecosystems.
Some bivalves, such as oysters, are known for producing pearls. When an irritant enters the mantle of the bivalve, layers of nacre (mother-of-pearl) are secreted to coat the irritant, forming a pearl over time. This process creates lustrous gems admired for their beauty. They can be found in shallow coastal areas, deep ocean floors, and even in brackish estuaries. This adaptability has contributed to the success and global distribution of bivalves.