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Mollusks. Mollusk Features. Complete digestive system Bilateral symmetry Move on muscular foot 3 part body plan A) Radula tongue-like organ to scrape food B) Mantle Covers internal organs secretes shell C) Ctenidia Gills to extract oxygen. water. Mollusk Features. Have organ systems
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Mollusk Features • Complete digestive system • Bilateral symmetry • Move on muscular foot • 3 part body plan • A) Radula • tongue-like organ to scrape food • B) Mantle • Covers internal organs • secretes shell • C) Ctenidia • Gills to extract oxygen water
Mollusk Features • Have organ systems • Usually separate male/female sexes • Methods vary • Snail “love-darts” • Shells • made of protein and calcium • Some internal
Gastropods: slugs, snails • “Stomach Foot” • Mostly marine • Most single shell • Foot secretes slime to move • Feeding: • Herbivores: scrape food with radula • Predators: poisonous dart to swallow prey whole
Bivalves: clams • Most marine • Shell secreted by mantle • No distinct head region or radula • Filter feeders • Sperm & egg released into water • Larvae free swimming
Cephalopods: squid, octopus • “Head foot” • Large head attached to tentacles • Complex nervous system & brain • Expel water through siphon to move • Jet propulsion • Active predators