: Some species (pearl oysters) produce pearls and mother-of-pearl (nacre) used in jewelry.
: As filter feeders, they clean bodies of water by removing organic suspension.
: Like most mollusks, they have an open circulatory system where the heart pumps blood into the body cavity. Internal Anatomy Summary Characteristic Digestive gdz biologiia 7 sumatokhin klass dvukhstvorchatye molliuski
: Consists of two symmetrical valves connected by a flexible ligament and a "lock" (hinge).
: The body is laterally compressed and divided into two main parts: the trunk and the wedge-shaped foot . Unlike gastropods, bivalves lack a head, tentacles, and eyes. : Some species (pearl oysters) produce pearls and
: They are filter feeders . Water enters through an inhalant siphon, passes over the gills where food particles are trapped, and exits through an exhalant siphon.
Урок 2: Классы моллюсков - Ростелеком Лицей : They are filter feeders
: Species like oysters, mussels, and scallops are important food sources for humans and marine life.