Gdz Biologiia 7 Sumatokhin Klass Dvukhstvorchatye Molliuski Onlain Apr 2026

: The body is laterally compressed and enclosed in a bilateral shell. This shell consists of three layers: an outer organic layer (periostracum), a middle calcareous layer, and an inner pearly layer (nacre).

: The nervous system is simplified, consisting of three pairs of ganglia. Ecological and Economic Importance

: Many species, such as scallops and oysters, are significant food sources for humans. Freshwater pearl mussels are also cultivated for pearl production.

: They breathe through plate-like gills (ctenidia) located in the mantle cavity.

: Most bivalves are filter feeders. They draw water into their mantle cavity through a siphon, where specialized gills trap organic particles. Internal Systems

: Unlike gastropods (snails), bivalves lack a distinct head. Their body consists of a torso and a muscular "foot" used for burrowing or anchoring.

: By filtering vast amounts of water, bivalves like mussels and oysters act as natural water purifiers in ecosystems.

: The body is laterally compressed and enclosed in a bilateral shell. This shell consists of three layers: an outer organic layer (periostracum), a middle calcareous layer, and an inner pearly layer (nacre).

: The nervous system is simplified, consisting of three pairs of ganglia. Ecological and Economic Importance

: Many species, such as scallops and oysters, are significant food sources for humans. Freshwater pearl mussels are also cultivated for pearl production.

: They breathe through plate-like gills (ctenidia) located in the mantle cavity.

: Most bivalves are filter feeders. They draw water into their mantle cavity through a siphon, where specialized gills trap organic particles. Internal Systems

: Unlike gastropods (snails), bivalves lack a distinct head. Their body consists of a torso and a muscular "foot" used for burrowing or anchoring.

: By filtering vast amounts of water, bivalves like mussels and oysters act as natural water purifiers in ecosystems.