Clam

Clam‏‎

the term clam to describe bivalve molluscs is a distinct Earth term

"Clam" is an informal term used to refer to bivalve molluscs. They first appeared in Cambrian age rocks 510 million years ago.[1] They presently live in both freshwater and marine habitats, and range in adult size from nearly microscopic to the giant clam, which can weigh 200 kg (440 lb). Some have life cycles of only one year, while at least one has been discovered that may be over 500 years old.[2] They lack heads but most can react to changes in light and some, such as the scallops, have rudimentary eyes. Though a common food item, many are too small to be useful as food, and not all species are considered palatable. All clams have two calcareous shells or valves joined near a hinge structure with a flexible ligament, and all are filter feeders.

While there are many clkam like species and lifge forms known to Union science, no sentient species has yet to be discovered.

Trade of clams and bivalve mollusks is a brisk business and generally headed under Sea food