Phylum Porifora Phylum Cnidaria Chapter 9 Notes Phylum

Phylum Porifora & Phylum Cnidaria Chapter 9 Notes

Phylum Porifora • Sponges - porifora = “bears pores” • Habitat: Mostly Marine • Sessile (cannot move) • Sexual or Asexual – Monoecious – both sexes in the same individual – Asexual gemmules – released when parent dies in winter – Asexual regeneration • Filter feeders – Eat particles

Phylum Porifora • Loosely organized cells No tissues or organs • Evolutionarily, most primitive animals • ~9, 000 species • Size from <1 cm - 2 m • Asymmetrical/ superficially radially symmetrical • Central cavity & branching chambers – Used to circulate water

Phylum Porifera • 3 Types of Cells – Pinacocytes “pea-knock-o-cytes” • Thin, flat cells • Line outer surface of sponge • Porocytes – regulate water circulation – Mesenchyme cells • • • “Amoeboid cells” Middle, jellylike layer Reproductive cells Secrete skeletal elements Transport and store food – Choanocytes “funnel - cell” • • Inner layer “collar cells” – ring of cells with microvilli surrounding a flagellum Flagellated Creates water currents through the sponge

Phylum Porifora • Sponges skeleton – Spicules - Microscopic needlelike spikes – Spongin – fibrous protein made of collagen

Important Groups of Porifora • Calcarious Sponges – Spicules made of calcium carbonate – Spicules are needle shaped – All marine • Glass Sponges – Spicules made of silica • Bath Sponges – Colorful sponges – Siliceous spicules or spongin or both – 1 family of freshwater sponges

Phylum Cnidaria

Phylum Cnidaria Number of Species • 9, 000+ Species Habitat • All aquatic • Mostly Marine Food Source • Small crustaceans & fish

Phylum Cnidaria Unique Characteristics: • Important in coral reef ecosystems • Have specialized cells ‘cnidocytes’ – Epidermal/gastrodermal cells – Used in defense, feeding, and attachment • Produce cnidae – a fluid-filled, intracellular capsule enclosing a coiled, hollow tube – Ex: Nematocysts (a type of cnidae) – Contain barbs to penetrate prey

Phylum Cnidaria Important groups: • Jellyfish • Anemones • Corals

Phylum Cnidaria Body Structure • Radial or biradial symmetry (oral/aboral) • Have tissues! (…and I don’t mean kleenex…) • Diploblastic (endoderm + ectoderm +mesoglea) • Specialized cells – – – Food gathering Defense Digestion Absorption • Medusa (dioecious & free swimming) or polyp (sessile & asexual) Skeletal Support • Hydrostatic skeleton – water-filled gastrovascular cavity

Phylum Cnidaria Digestion/Food Capture: • Nematocysts – entangle and paralyze prey • Tentacles contract to bring food to the mouth • Enzymes and lysosomes break down the food in gastrovascular cavity • Makes a sort of soupy mixture • Phagocytosis

Phylum Cnidaria Muscular Movement: • Pulsate muscles to move tentacles in an inchworm fashion and glide • Nutritive muscular cells move materials in and out of the gastrovascular cavity Nervous Communication: • Primitive nerve net – does not lead to anything

Excretory Waste Removal & Respiration • Both processes occur in the gastrovascular cavity • Cnidarians have a large surface-area-tovolume ratio – All cells are near body surface – O 2, CO 2, and nitrogenous wastes exchange by diffusion

Reproduction • Mostly dioecious • Sperm & egg released from gastrovacular cavity – Planula = ciliated, free-swimming larva forms polyp – Polyps reproduce by budding forms medusa • Alternation of generations life cycle