1. Phylum within Kingdom Animalia

2. Prorifera Multicellular with little or no tissue organization No segmentation No backbone Body is in the form of a sac-like structure consisting of three layers -The cavity of this sac is called the spongocoel Commonly referred to as Sponges Have bodies consisting of pores and channels allowing water to circulate through them A matrix of mesophyl acts as an endoskeleton

3. Cnidaria No segmentation Lack an endoskeleton and backbone Exhibit radial symmetry Common Name Sea Anemones, Corals and Jellyfish • Body consists of two tissue layers • - inner layer lines the gut cavity called the gastrovascular cavity

4. Platyhelminthes Lack a body cavity and backbone No true endoskeleton Commonly referred to as flatworms No segmentation The first organisms to demonstrate bilateral symmetry • The first organisms to have tissues organized into organs • - 3 major organ systems: nervous system, excretory system, and digestive tract

5. Nematoda Have complete gut (body cavity) that consists of two openings Have 3 layers of tissue that give rise to organs No segmentation Show bilateral body symmetry Commonly referred to as roundworms Lack a backbone and endoskeleton

6. Mollusca Show bilateral symmetry Have a fluid filled body cavity called a coelom No segmentation or backbone Commonly referred to as mollusks Do not possess an endoskeleton Contain organs derived from tissue

7. Annelida Organs derived from organized tissue Show bilateral symmetry Commonly called segmented worms Absence of a backbone Segmented body Have a fluid filled body cavity called a coelom Considered soft bodied organisms therefore do not have an endoskeleton

8. Arthropoda Lack endoskeleton but do possess an exoskeleton made of chitin Segmented body plan Lack a backbone Bilateral body symmetry Have a fluid filled body cavity called a coelom Organs derive from 3 tissue layers Consists of and commonly called insects, spiders, and crustaceans

9. Echinoderm Commonly called starfish, sea urchins, and sand dollars Organs derived from 3 tissue levels Have a fluid filled body cavity called a coelom Lack a backbone No segmentation in body plan Endoskeleton made of calcium Pentamerous radial body symmetry

10. Chordata AKA “vertebrates” Bilateral body symmetry Body consists of organs and muscles derived from tissue layers Endoskeleton allows for muscle attachment Possess a backbone Segmented body plan Possess a body cavity called a coelom