P HYLUM P ORIFERA (Sponges)

PHYLUM PORIFERA(Sponges) ~9000 species FACT: A sponge that is 10cm tall must filter more than 100L of water a day to stay alive!!

PORIFERA • “pore bearer” • many pores (openings) on the surface • Perhaps one of the earliest animals to evolve • Fossil evidence of sponge “spicules” over 600 millions years old

PORIFERA • MULTICELLULAR • cells are specialized but do not form organized “tissues” or organs • GERM LAYERS • Only endoderm and ectoderm • Endoderm – forms inner cell types • Ectoderm – forms outer cell types

PORIFERA • MOVEMENT • Larvae stage is motile (moving) • Mature form is sessile (non-moving)

PORIFERA • REPRODUCTION • SEXUAL • monoecious = produce both sperm and eggs • broadcast spawn = sperm shed into water • sperm taken up by incurrent of neighbouring sponges • egg + sperm  zygote  swimming larva adult • ASEXUAL • budding – “mini-me” buds off from the adult’s body • gemmules - groups of cells with a tough coat that survive dry periods and winter seasons (similar to spores)

PORIFERA • BODY ORGANIZATION • no body cavity because no true mesoderm • asymmetrical • non-segmented • no tissues or organ systems (just specialized cells)

PORIFERA • DETAILED STRUCTURE

PORIFERA • DETAILED STRUCTURE • Two cell layers with jellylike material between • Endoderm – inside “skin” • Ectoderm – outside “skin” that is protective • “middle area” containing amebocytes cells and spicules • Spicules provide structure and protection • Made up of: • Calcium • Silicon (glass) • Spongin (protein)

PORIFERA • SPECIALIZED CELLS • Collar cells/Choanocytes • on the inside of sponge • flagella beat to draw in H2O (incurrent) • digest food and pass on nutrients to amebocytes • Amebocytes • in “gel-like” layer • carry nutrients, gasses and waste throughout sponge

PORIFERA • BODY SYSTEMS • REPRODUCTIVE SYSTEM – not a true system • specialized cells = sperm and egg • monoecious = a sponge can make both egg and sperm • also asexual reproduction (budding) • DIGESTIVE SYSTEM – not a true system • filter feeds – food enters with water • water enter via tiny pores (ostia) = incurrent • water exits via massive pore (osculum) = excurrent • Collar cells (choanocytes) engulf and digest food

PORIFERA • BODY SYSTEMS • CIRCULATORY SYSTEM – not a true system • specialized cells = amebocytes circulate nutrients to other cells in the sponge • RESPIRATORY SYSTEM – not a true system • gas exchange directly between cells and water by diffusion (O2diffuses into and CO2 out of cells) • water enters via tiny pores (ostia) = incurrent • water exits via massive pore (osculum) = excurrent

PORIFERA • BODY SYSTEMS • EXCRETORY SYSTEM – not a true system • specialized cells = amebocytes can help remove waste from other cells in the sponge or cells release waste directly to water • Water enter via ostia = incurrent • Water exits via osculum = excurrent • NERVOUS SYSTEM – NONE • MUSCULAR SYSTEM – NONE • SKELETAL SYSTEM – NONE

PORIFERA • GENERAL INFORMATION • HABITAT • mostly warm marine waters (marine = salt water) • some freshwater species • e.g., Grantia (microscope slide) • SIZE • as small as 0.5 cm tall • as large as 2 meters tall

PORIFERA • GENERAL INFORMATION • Classes • Demospongea – contains spicules made of spongin • Hexactinellida – contains spicules made of silicon dioxide (glass) • Calcarea - contains spicule made of calcium carbonate (bone-like) • Demospongea Hexactinellida Calcarea

PORIFERA • GENERAL INFORMATION • From http://cgc.rncan.gc.ca/marine/index_e.php • SPONGE REEFS • thought to be abundant during Jurassic period (200 mya) • were once thought to be extinct • in early 1990’s 4 sponge reefs were found off the coast of BC in Hecate Strait and Queen Charlotte Sound

PORIFERA • GENERAL INFORMATION • ECONOMIC SIGNIFICANCES • harvested from Gulf of Mexico and Greece • used for cleaning • spicules of spongin = abrassive • ability to hold large amounts of water • replaced with synthetic materials to protect ecosystems

P HYLUM P ORIFERA (Sponges)