1. Metazoa
2. Porifera
3. Eumetazoa
4. Cnidaria
4.1. Medusozoan
4.1.1. Scyphosoan
4.1.2. Cubozoan
4.1.3. Hydrazoan
4.2. Anthozoa
4.2.1. Coral
4.2.2. Sea anemone
5. Lophotrochozoa
5.1. All have bilateral symmetry and triplobastic development
5.2. Most have a coelom and digestive tract with two openings
5.3. Some develop a lophphore for feeding
5.4. Some have a trochophore larval stage
5.5. Few have neither
5.6. Platyhelminthes (flatworms)
5.6.1. Are acoelomates
5.6.2. Are gastrovascular cavity with one opening
5.6.3. Gas exchange takes place across the surface by diffusion
5.6.4. Protonephrida regulate the osmotic balance
5.6.5. Catenulida (chain worms)
5.6.5.1. Reproduce asexually by budding
5.6.6. Rhabditophora
5.6.6.1. Free living example: planarians
5.6.6.2. Parasistic examples:
5.6.6.2.1. Trematodes
5.6.6.2.2. Tapeworms
5.7. Rotifers
5.7.1. Truly multicellular with specialized organ systems
5.7.2. Have alimentary canal: digestive tube with separate mouth/anus within fluid-filed pseudocoelom
5.7.3. Reproduce by pathenogenesis: female producing offspring from unfertilized eggs
5.8. Lophophorates
5.8.1. Have lophophore: a crown of cilliated tentacles around the mouth
5.8.2. Have true coelom
5.8.3. Ectoprocts (bryozoans)
5.8.3.1. Sessile
5.8.3.2. Colonial (slightly resemble plants)
5.8.3.2.1. Exoskeleton encases colony
5.8.3.2.2. Some species are reef builders
5.8.4. Brachipods
5.8.4.1. Marine
5.8.4.2. Slightly resemble clams but with two halves of shell being dorsal and central rather than just lateral like with clams
5.9. Molluscs
5.9.1. All have muscular foot, visceral mass, and mantle
5.9.2. Most have water-filled mantle cavity
5.9.3. Feed using rasplike radula
5.9.4. Polyplacophora (chitons)
5.9.4.1. Encased in armor of eight dorsal plates
5.9.5. Gastropoda
5.9.5.1. Have spiraled shell which protects from injury and predators and prevents dehydration
5.9.6. Bivalvia
5.9.6.1. Examples: clams, oysters, mussels, scallops
5.9.6.2. Mantle cavity contains gills for feeding and gas exchange
5.9.7. Cephaloda
5.9.7.1. Examples: squid, octopi
5.9.7.2. Use beak-like jaws and tentacles for feeding
5.9.7.3. Have, complex brain, circulatory system, and well-developed sense organs
5.10. Annelid
5.10.1. Coelomates with bodies composed of series of fused rings
5.10.2. Errantia
5.10.2.1. Mobile, marine organism
5.10.2.2. Most have parapodia: paddle-like "feet" on each body segment
5.10.2.3. Each parapodium has numerous chaetae: bristles made of chitin
5.10.3. Sedentaria
5.10.3.1. Less mobile
5.10.3.2. Some burrow into substrate, other live in protective tubes (tube-dwelling)
5.10.3.3. Leeches
5.10.3.3.1. Parasites that suck blood
5.10.3.3.2. Secrete chemical called hirudin to prevent blood from clotting
5.10.3.4. Earthworms
5.10.3.4.1. Have cuticle