Bivalvia is a class of mollusks within the phylum Mollusca, commonly known as bivalves. This diverse group consists of aquatic animals characterized by a two-part hinged shell, which is also referred to as a "valve." The name "bivalvia" is derived from the Latin words "bi," meaning two, and "valva," meaning folding door.
Bivalves possess a unique body structure, comprising a soft and elongated body enclosed by the two shell valves. The shells are made of a mineral substance called calcium carbonate and are usually symmetrical along the midline, allowing the animal to close and protect itself. The shells are linked by a flexible ligament, which enables the bivalve to open and close its shell valves.
These organisms typically inhabit diverse aquatic environments, including freshwater, marine, and even brackish habitats. Bivalves are known for their remarkable ability to filter feed, using specialized structures called gills to extract microscopic food particles, such as plankton, from the water column.
Bivalvia encompasses a wide range of species, including clams, mussels, oysters, scallops, and cockles, among others. They are economically and ecologically significant, as they serve as a food source for humans and other animals and provide important ecosystem services, such as water filtration and stabilization of sediment. Bivalves have a rich fossil record, dating back hundreds of millions of years, making them an important group for paleontologists studying Earth's history and evolution.
