PHYLUM PORIFERA Basics heterotrophic and cellular level with specialized cell types Locomotion none sessile attached to substrate Sensory nerves no specialized structures Circulation transport no specialized structures diffusion cell to cell Osmoregulation excretory no specialized structures simple diffusion with environment water Respiration simple diffusion with environment water Feeding suspension filter feeders using choanocytes with microvilli with intracellular digestion Reproduction mostly monoecious asexual by external budding fragmentation and gemmules o usually sequential hermaphrodites both sexual asexual modes o Asexual a gemmule for freshwater sponges is a dense hardened ball of archaeocytes in the mesohyl protected by collagen and spicules used for protection to allow overwintering o Sexual fusion of egg sperm gametes when the stimulus is right specialized flagellated choanocytes become sperm and are released into the water the fertilized egg develops into a simple parenchymula or amphiblastula larva a ball of cells with flagella on the outside the larva exits the parent sponge swims for a few hours then settles and develops into a new sponge Skeletal Support 2 components spicules and structural protein matrix Normally collagen another sponging a form of collagen Beating flagellated collar cells choanocytes line the spongocoel atrium and produce currents that bring water food into incurrent pores in the sponge wall termed ostia singular ostium into canals or a central cavity and out through the osculum opening Architecture Cell Types Pinacocytes outer sponge cells thin leathery and tightly packed together and collectively form the pinacoderm Mesohyl gelatainous proteinacous matrix beneath the outer pinacoderm layer in which some cells amebocytes and skeletal elements such as spicules spongin fibers are embedded Porocytes surround canal openings pore can contract to regulate water flow through the sponge Archaeocytes aka amebocytes amoebocytes totipotent cells i e can change into any other type of sponge cell move through mesohyl can turn into eggs Sclerocytes derived from archaeocytes responsible for the secretion of stiff skeletal elements called spicules Spongocytes also derived from archaeocytes secrete skeletal fibers made of the structural proteins collagen spongin 3 types of Body Types Asconoid archaeocyte amoebocyte mesohyl Synconoid Leuconoid 3 Classes Within Phyla Profiera classified by spicule morphology Hexactinellida glass sponges produce silicious spicules Commonly called glass sponges because of the 6 sided silicious spicules characteristic of the class Hexaxons are joined to each other to form complex cages marine don t have distinct cells cell layers are syncytial mass of protoplasm with many nuclei synconoid and leuconoid Demospongiae mostly silicious spicules in addition to spongin fibers Comprise 80 percent of living extant species of sponges Mostly marine only 150 freshwater species leuconoid in form Skeletal support from fibers of spongin a type of collagen protein siliceous spicules less often CaCO3 or both Calcarea produce calcium carbonate spicules Produce three and four rayed calcium carbonate spicules Includes all three sponge architectures asconoid syconoid and leuconoid All species are marine Sponge Life Cycle Ecological Roles often dominant structural elements in marinescapes important for water filtration bacteria size particles influence water chemistry provide refuge snappng shrimp juvenile spiny lobsters RADIATA Phyla Cnidaria and Ctenophora Basics Cnidaria Radial Symmetry Multicellular with true tissues diploblastic 2 germ layers and a blind gut with 1 opening Locomotion slow swimming or sessile attached to substrate Sensory nerves nerve net rhopalia statocysts ocelli in scyphozoan medusae primitive nerve net made up of nerve cells in the epidermis gastrodermis but no organs and no central control no brain Circulation transport gastrovascular canals in schyphozoan medusae Osmoregulation excretory no specialized structures simple diffusion with environment water Respiration simple diffusion with environment water Feeding mostly carnivorous capture prey with tentacles extracellular intracellular digestion has a GVC for capture of larger prey extracellular digestion then smaller particles are intracellularly digested in food vacuoles Reproduction both monoecious dioecious species both sexual asexual modes Polyps can reproduce asexually by budding fission or pedal laceration forming new polyp clones If sexual reproduction interstitial stem cells give rise to gametes in reproductive polyps or medusae that are released for fertilization Zygote develops into a free swimming multicellular ciliated planula larva that will settle and form a new polyp Skeletal support a hydrostatic skeleton The hydrostatic skeleton in a cnidarian consists of the fluid filled gut GVC that works with an outer epitheliomuscular cell layer with longitudinal myofibrils and an inner gastrodermal nutritive muscular cell layer with circular lateral myofibrils no excretory respiratory or circulatory organs gas exchange and elimination of metabolic wastes via diffusion across cells of the body wall Basic Architecture Body wall consists of two tissue layers an outer epidermis formed from ectoderm an inner gastrodermis formed from endoderm There is an acellular layer of mesoglea jelly separating the two layers NOTE no mesoderm gastrula is only diploblastic Body encompasses a 2 way blind sac incomplete gut or gastrovascular cavity GVC which communicates with the surrounding medium through a single opening or mouth actually mouth anus surrounded by tentacles that capture prey Two Body Types Polyp cylindrical generally attached to a substrate but some can glide solitary or colonial tentacles surround a mouth that faces away from substrate generally upward in some species e g corals polyp may secrete hard calcareous skeletal material Medusa umbrella shaped bell floats or swims by contraction tentacles surround mouth that generally faces downward Cnidaria may exist in polyp or medusa forms only or alternate between the two phases Cell Types Cnidarians derive their name from cnidocyte cells Cnidocytes contain organelles called cnidae cnidum sing the most common cnidae are nematocysts stinging cnidum that eject harpoon like barbed stinging toxin threads a cellular organelle capped by an operculum within a cnidocyte cell The cnidocil is the hair like trigger that causes the
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