Trying to remember all those phyla! Invertebrates Review Trying to remember all those phyla!

Porifera sessile (don’t move) with porous bodies Lack tissues and organs (no nerves or muscles) Filter feed by drawing water through pores Choanocytes: cells ingest bacteria and particulate food suspended in the water Ex. Sponges!

Cnidaria Radial symmetery a gastrovascular cavity (one opening) Carnivores: possessing tentacles armed with cnidocytes (stinging capsules) that aid in defense and capture of prey Two body forms: sessile polyps and floating medusas Ex. Hydras, jellies, sea anemones, coral

Ctenophora Comb jellies possess rows of ciliary plates for locomotion Use retractable tentacles to catch food Tentacles bear adhesive colloblasts When prey contact a colloblast it releases a sticky thread that will capture the food Tentacle is then wiped into the mouth! Yum!

Platyhelminthes Acoelomates with gastrovascular cavities Triploblastic Tapeworms lack a digestive tract altogether and absorb nutrients across the body surface Triploblastic Ex. Flatworms (planaria!), flukes, tapeworms

Rotifera Tiny animals that mainly inhabit freshwater Multicellular and have specialized organs Complete digestive tract pseudocoelomates with jaws and crowns of cilia that draw water into the mouth Parthenogenetic: females can produce more females from unfertilized eggs

Lophophorates Coelomates Lophophore: a horeseshoe-shaped, suspension-feeding organ bears ciliated tentacles that surround the mouth Ex. Bryozoans – colonial organisms that live on reefs Ex. Phoronids – tube-dwelling marine worms Ex. Brachiopods – looks like a clam

Nemertea Proboscis worms are named for their prey-capturing apparatus Unique retractable tube used for defense and prey capture Acoelomate, but contains a fluid filled cavity Complete digestive tract and a closed circulatory system (blood is in vessels) Ex. Proboscis worms

Mullusca Muscular foot: used for movement Visceral mass: contains internal organs Mantle: fold of tissue that secretes a shell Most have separate sexes, but many snails are hermaphrodites, Ex. Snails, slugs, oysters, clams, octopuses, and squid

Interesting! 

Annelida Segmented worms, with a Coelom Have a digestive tract, blood vessels, and nerve cord that run the length of the animal Closed circulatory system: network of vessels contain blood with oxygen carrying hemoglobin Skin used for respiration Metanephridia: excretory tubes Hermaphrodites but cross fertilize Ex. Earthworms and leeches

Nematoda Roundworms: nonsegmented pseudocoelomates Tough exoskeleton – cuticle - covers the body Complete digestive tract, but lack a circulatory system Sexual reproduction

Arthropoda Segmentation Hard exoskeleton: cuticle – constructed from layers of protein and chitin Jointed appendages Well developed sensory organs: extensive cephalization Open circulatory system: organs bathed in hemolymph Ex. Spiders, ticks, scorpions, millipedes, mites, centipedes, insects, crabs, lobsters, shrimp

Echinodermata Sessile or slow moving Radial adults, bilateral larvae Water vascular system, a network of hydraulic canals branching into extensions called tube feet function in locomotion, feeding, and gas exchange Sexual reproduction Ex. Sea stars, sea urchins, sand dollars, sea cucumbers

Checking for Understanding #1 Which phyla is characterized by animals that have segmented bodies? A. Cnidaria B. Platyhelminthes C. Porifera D. Arthropoda E. Mollusca

Checking for Understanding #2 Although a diverse group, all cnidarians are characterized by ______. A. a gastrovascular cavity B. an alteration between a medusa and polyp stage C. some degree of cephalization D. muscle tissue of mesodermal origin E. the complete absence of sexual reproduction

Checking for Understanding #3 A land snail, a clam, and an octopus all share ________. A. a mantle B. a radula C. gills D. embryonic torsion C. distinct cephalization

Checking for Understanding #4 Which of the following is NOT a characteristic of most members of the phylum Annelida? A. hydrostatic skeleton B. segmentation C. metanephridia D. pseudocoelom E. closed circulatory system