5 Main Groups of Invertebrates 1. Porifera (Sponges) - Simple aquatic animals with porous bodies that filter water for food.2. Cnidaria (Coelenterates) - Radially symmetrical animals like jellyfish, sea anemones, and corals with stinging cells.3. Platyhelminthes (Flatworms) - Soft-bodied, flattened worms, some of which are parasitic.4. Annelida (Segmented Worms) - Worms with segmented bodies like earthworms and leeches.5. Arthropoda - The largest group, including insects, spiders, crustaceans, and others featuring jointed limbs and exoskeletons.