Interesting Invertebrates

What you’ll learn

• Sponges (Porifera) filter water through pores and lack true tissues; cnidarians have stinging cells and often radial symmetry.
• Flatworms, roundworms, and segmented worms show different answers to bilateral bodies, guts, and habitats.
• Mollusks include bivalves, gastropods, and cephalopods; arthropods have jointed legs and must molt their exoskeletons.
• Echinoderms are marine animals with radial symmetry (often five part) and a water vascular system with tube feet.