OCEA 80A – Life in the Sea Fall 2009 Outline of notes on marine invertebrates I. Topics in invertebrate biology A. Body symmetry 1. Bilateral symmetry 2. Radial symmetry - consequences of radial symmetry? B. Habitat 1. Benthic 2. Pelagic 3. Infaunal C. Reproduction 1. Monoecious (hermaphroditic) vs. dioceious (separate sexes) 2. Free-spawning 3. Brooding D. Larval development 1. Indirect development 2. Direct development E. Feeding 1. Predation (a) passive predation (b) active predation 2. Herbivory 3. Suspension feeding (incl. filter feeding) 4. Deposit feeding II. Phylum Mollusca A. Features of the phylum 1. Calcareous shell 2. Foot 3. Radula B. Molluscan groups 1. Gastropoda 2. Bivalvia – 2 equal shells 3. Cephalopoda 4. Polyplacophora – 8 shell plates III. Phylum Arthropoda, Subphylum Crustacea A. Features of the phylum 1. Segmented body 2. Jointed exoskeleton B. Crustacean groups 1. Crabs 2. Barnacles 3. Many others - copepods - isopods - shrimps - krill 4. Crustacean larval forms IV. Phylum Annelida, Class Polychaeta – marine segmented worms A. Features of the phylum 1. Segmented body 2. Bilateral symmetry 3. Parapodia with bristles on sides of body B. Polychaete lifestyles 1. Free crawling 2. Tube dwelling 3. Swimming V. Phylum Cnidaria A. Features of the phylum 1. Benthic and pelagic forms 2. Polyp and medusa 3. Two-way gut 4. Cnidocytes B. Generalized cnidarian life cycle C. Asexual reproduction 1. Colonies 2. Clones D. Cnidarian groups 1. Anthozoans – anemones, corals, etc. (a) polyps only; no medusa stage (b) zooxanthellae (some) (c) coral bleaching 2. Hydrozoans – hydroid colonies, siphonophores, chondrophores (a) polyps and medusae present (b) examples of neuston – man-o-war, by-the-wind sailor 3. Scyphozoans – large medusae (a) polyps and medusae present (b) life cycle of the moon jelly VI. Phylum Echinodermata A. Features of the phylum 1. Pentaradial symmetry 2. Water vascular system B. Echinoderm groups 1. Asteroids – sea stars 2. Ophiuroids – brittle stars 3. Echinoids – sea urchins and sand dollars 4. Holothurians – sea cucumbers VII. Phylum Chordata A. Features of the phylum 1. Dorsal, hollow nerve cord 2. Pharyngeal gill slits 3. Notochord 4. Post-anal tail B. Invertebrate chordate groups 1. Ascidians – sea squirts (a) benthic filter feeders (b) colonial and solitary forms (c) tadpole larva 2. Salps (a) pelagic filter feeders, unidirectional water flow (b) colonial and solitary forms 3. Larvaceans (a) pelagic filter feeders, pulling water through a mucus house (b) marine snow 4. Cephalochordates – the lancelets ***Note: You will not need to know the following groups in detail, but you should be able to recognize the name and know what kind of animal it refers to.*** VIII. Miscellaneous invertebrate phyla A. Phylum Porifera – sponges - filter-feeders B. Phylum Ctenophora – comb jellies - swim using cilia - 8 comb rows of cilia C. Phylum Platyhelminthes – flatworms - parasites and others D. Phylum Chaetognatha – arrow worms - transparent pouncers, prey on copepods E. Phylum Echiura – spoon worms - e.g., fat innkeeper worm - a filter feeder, feeds by filtering water through a mucus net .