Invertebrates make up 95% of all animal species and do not have backbones. They are classified into eight categories: sponges, which have no symmetry; cnidarians like jellyfish that have stinging tentacles; mollusks such as clams and oysters that all have shells; echinoderms with spiny skin and internal skeletons; arthropods including insects, spiders, crabs, and centipedes with hard exoskeletons; and three types of worms - flatworms, roundworms, and segmented worms that live inside and on land and sea animals.

1. The Animal Kingdom Chapter 2 Lesson 1: Invertebrates

2. I. What are invertebrates? Animals without backbones 95% of all animals

3. II. How do we classify Invertebrates? Into 8 categories Sponge - simplest kind No symmetry Cnidarians – have arm-like parts with stingers (jellyfish) Mollusks – all have shells (clam, oysters)

4. 4. Echinoderms – Have spiny skin & an internal soft skeleton Arthropods – Largest group with hard exoskeleton Insects Arachnids (spiders) Crustacean (crab, shrimp) Centipede

5. Worms – 3 types Flatworm – live inside animals Roundworm – live inside animals Segmented – live on land (earthworms)