Bivalves (Clams, Mussels, Oysters)

This group gathers Mollusks subcategory members belonging to the class Bivalvia, mollusks enclosed within a pair of hinged shells, called valves, that a set of powerful muscles can clamp shut for protection or gape open to feed and breathe. It spans clams, burrowing into sand or mud with a muscular foot, mussels, which anchor themselves to rocks, pilings and other hard surfaces with tough protein threads called byssal threads, oysters, prized both as food and, in several species, for the calcium carbonate pearls some individuals form around an irritant lodged inside the shell, and scallops, unusual among bivalves for an ability to swim short distances by rapidly clapping their two valves together to jet away from a predator. Nearly every bivalve is a filter feeder, drawing water across gills that strain out microscopic algae and other suspended food particles, a feeding style that also makes many species useful, real-world indicators of local water quality.