Biology 3 Animal Diversity Dr. Terence Lee Protostomes and Deuterostomes Symmetry • Asymmetry – no symmetry • Radial Symmetry – circular or round • Bilateral Symmetry – usually has a head and tail 1 Sponges • Asymmetrical • No true tissues Jellies • Ctenophores • Cnidarians Cnidarians • Named after their stinging cells • Radially symmetrical • First true tissues 2 Cnidarians Sea Anemone Coral Coral Reef Alternation of Generations Protostomes and Deuterostomes 3 Protostomes and Deuterostomes • Name comes from embryonic development – Protostome = As the embryo develops, the first opening becomes the mouth – Deuterostome = As embryo develops, the first opening becomes the anus . The Worms 1. Flatworms 2. Roundworms 3. Segmented Worms Flatworms • Playhelminthes – First with bilateral symmetry – Only one opening to gut planarians 4 Round Worms • Nematoda – One-way digestive tract 5 Nematodes Segmented Worms •Annelids –Body is divided into sections –Lives in many different habitats Annelids • Polychaetes are marine worms • Means “many feet” 6 Annelids This plan most Mollusks resembles the chiton body plan • Major Characteristics 1. Mantle – secretes the shell Mollusks • Live in very diverse habitats (aquatic and terrestrial) • Very diverse body plans – Some have shells while others are soft bodied • Very diverse locomotion 7 Mollusks Types of Mollusks: 1.Chitons – this is the most primitive 2.Bivalves – clams, oysters, mussels, etc. Chitons Bivalves • Two shells attached by a hinge • All are filter feeders • Mostly immobile but some species can swim • Good fossil record 8 Bivalves (Clams) Filter feeders Muscular foot for digging Bivalves (Clams) Bivalves (Oysters) 9 Bivalves (Oysters) Bivalves (Mussels) Bivalves (Mussels) 10 Bivalves (Scallops) Gastropods (Snails) Gastropods (Slugs) 11 Gastropods (Slugs) Cephalopods Octopus Squid Cuttlefish Nautilus Arthropods • Major Characteristics – Exoskeleton – Needs to molt – Jointed Limbs – Lives in very diverse habitats 12 Structural Support • Exoskeleton – external – Arthropods (shell) – Size limitations • Endoskeleton – internal – Vertebrates (bones) Arthropods (Insects) • Three body parts Arthropods (Arachnids) • Two body parts 1. Head/Thorax 2. Abdomen 13 Arthropods (Arachnids) Arthropods (Crustaceans) • Copepods • Crabs • Lobsters • Isopods Arthropods (Crustaceans) 14 Protostomes and Deuterostomes Echinoderms • Spiny Skin • Pentamerous Symmetry • Marine • Hydrostatic Skeleton • Representatives Echinoderms 15.