Pelecypoda, also known as Bivalvia, is a class of mollusks characterized by their dual shell covering and soft, unsegmented body. The name "Pelecypoda" comes from the Greek words pelekys, meaning "hatchet," and poda, meaning "feet," which refers to their foot structure resembling a hatchet.
These animals are commonly referred to as bivalves or clams. They are aquatic organisms found in both freshwater and marine environments worldwide. The dual shells, also known as valves, are mirror images of each other and are hinged together by a flexible ligament allowing the bivalve to open and close its shells.
The body of a Pelecypoda is enclosed within the shells, featuring a head region with sensory organs and a mouth for feeding. Their body is covered by a mantle, a thin layer of tissue responsible for shell secretion and protection.
Pelecypoda display filter-feeding behavior, where they extend their paired siphons, drawing in water and filtering out microscopic organisms and organic particles as a source of nutrition. This feeding mechanism is facilitated by cilia lining the gills, which aid in the movement of water and food particles towards the bivalve's mouth.
Bivalves live a sedentary lifestyle, burrowing in sand or mud or attaching themselves to rocks or other surfaces. They play important ecological roles, serving as filter feeders, participating in nutrient cycling, and providing habitat for various organisms. Additionally, bivalves also have economic significance as food sources for human consumption and as indicators of environmental health due to their sensitivity to water pollution.
