The Animal Kingdom

Chapter 2

Lesson 1: Invertebrates

I. What are invertebrates?

A. Animals without backbones

B. 95% of all animals

II. How do we classify Invertebrates?

A. Into 8 categories

1.Sponge- simplest kind

• No symmetry

2.Cnidarians – have arm-like parts with stingers (jellyfish)

3.Mollusks – all have shells (clam, oysters)

4. Echinoderms – Have spiny skin & an internal soft skeleton

5.Arthropods – Largest group with hard exoskeleton

• Insects

• Arachnids (spiders)

• Crustacean (crab, shrimp)

• Centipede

6.Worms – 3 types

• Flatworm – live inside animals

• Roundworm– live inside animals

• Segmented – live on land (earthworms)