Echinoderms and Mollusks. Invertebrates 2: Porifera , Cnidarians, Echinoderms, and Mollusks. Phylum Mollusca. Section 27-4. Over 80,000 different species of mollusks 2 nd largest phylum in the animal kingdom . . Mollusk. Soft bodies covered with a mantle.
Invertebrates 2: Porifera, Cnidarians, Echinoderms, and Mollusks
live in burrows on the deep-sea floor.
live in the depths of the ocean
Live on rocky shorelines and graze on plants.
Long tube-shaped shell tapered at one end with both ends open.
Burrow into the sand.
Nudibranchs – No Shell (Slugs)
Sea hare – Defense System
to burrow into the
soft sand and mud.
Scallops – Free Swimming
Blue-Ringed Octopus – Very small but deadly
Cuttlefish – Changes color
Comparing the Three Major Groups of Mollusks
Two shells held together by oneor two muscles
Internal shell orno shell
Muscular foot located on ventral side and used for movement
Burrowing species have muscular foot. Surface-dwelling species have either no foot or a “reduced” foot.
Head is attached to a single foot. The foot is divided into tentacles or arms.
Snail, slug, sea hare, nudibranch
Clam, oyster, mussel, scallop
Octopus, squid, cuttlefish, nautilus
over the bottom of the ocean floor.
stomach into the clam
to digest its soft
The Anatomy of a Starfish
Some Examples are….