Mollusks

Mollusk Features True coelum Bilateral symmetry 3 part body plan A) Visceral Mass: central section; contains organs B) Mantle: Tissue that secretes shell C) Muscular Foot

Mollusk Features Have organ systems Usually separate male/female sexes Shells: made of protein and calcium Radula: tongue-like organ to scrape food

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

Poor fishy

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

The Cuttlefish

The Cuttlefish in Action