Урок 2: Классы моллюсков - Ростелеком Лицей
: 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. gdz biologiia 7 sumatokhin klass dvukhstvorchatye molliuski
: 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.
(class Bivalvia ) are a unique group of aquatic mollusks characterized by a shell consisting of two hinged valves and, most notably, the absence of a head . In the Grade 7 Biology curriculum by Sumatohin, they are studied as essential bio-filters and members of aquatic ecosystems. Key Biological Features : They are filter feeders
Mouth (near the foot), stomach, liver, and intestine. They lack a radula (grating tongue). Plate-like gills (ctenidia) located in the mantle cavity. Excretory Two kidneys that open into the mantle cavity. Nervous Simplified, consisting of three pairs of ganglia. Ecological and Economic Importance
: Like most mollusks, they have an open circulatory system where the heart pumps blood into the body cavity. Internal Anatomy Summary Characteristic Digestive In the Grade 7 Biology curriculum by Sumatohin,
: As filter feeders, they clean bodies of water by removing organic suspension.