MARB 435 Lecture 6 Outline of Last Lecture 1 Writing Lab Library Research Presentation 2 Locomotion of Plankton 3 Vertical Migration 4 Continuous Plankton Recorder CPR 5 Ocean Acidification 6 Possible Effects of Plankton Outline Current Lecture 1 Phylum Porifera Sponges Introduction 2 Sponge Cells Body Wall Structures and Functions 3 Sponge Tissues 4 Levels of Complexity of Sponges 5 Sponge Taxonomy 6 Class Calcarea 7 Class Demospongiae a Demosponge Diversity 8 Class Hexactinellida 9 Feeding and Nutrition 10 Cladorhizidae Carnivorous demosponges 11 Bioactive Metabolites 12 Sponge Natural Products 13 Bioerosion 14 Sponge Symbionts 15 Gemmules 16 Sexual Reproduction 17 Development 18 Sponge Reefs 19 Reef Building Sponges 20 Conservation Current Lecture Phylum Porifera Mainly and some freshwater species of Porifera are common and there are 7 000 to 15 000 species They have choanocytes and are suspension feeders Sponges lack organs epithelia and symmetry Choanocytes are a Synapomorphy shared character trait for sponges Sponges represent the second largest biomass on tropical reefs after corals Sponge Cells Body Wall Structures and Functions 1 Archaeocytes Ameoboid cells which are essential in reproduction 2 Pinacoderm The outermost layer of cells in sponges 3 Mesohyl It s a gelantenious matrix between the pinacoderm and choanoderm of sponges commonly the middle layer 4 Choanocyte Cells that line the internal chambers of sponges 5 Choanoderm A layer of choanocytes and is the lower layer of sponges 6 Sclerocyte Is a type of spicule found in sponges 7 Spicules Tiny spike like structures found in the skeleton of sponges 8 Pinocyte A cell which undergoes pinocytosis which are fluids that that enter a cell by invagation 9 Ostium An opening into the sponges body cavity 10 Porocyte These are tubular cells that make up the pores of a sponge Sponge Tissue Sponge s tissues are dynamic and contain complex parts The mesohyl cells are amoeboid and are in more or less constant motion The pinacocytes and choanocytes can move to reorganize the aquiferous system Absence of basal lamina and intercellular junctions allows independent and frequent cell movements Levels of Complexity There are three levels of complexity for sponges asconoid syconoid and leuconid Asconoid Simple sponges with a smooth body wall They are simple base shaped with pores The pores allow water to move through and throughout the sponge The sponges move the with flagella If the sponges grow too big the flagella wouldn t be able to efficiently pump water which results in stagnant water inside the sponge Ex Leucosolenia sp Clathrina clathrus Syconoid These sponges are a little more complex and they have bubble son the outside making the body wall bumpy They range in size but an example of a small syconoid sponge is Grantia sp and Sycon Sp they grow to be one inch in size Choanocytes chambers are also present in syconoid sponges Leuconoid These are the largest types of sponges They have a large surface area to volume ration Examples Haliclona sp Cliona sp and Aplysnia sp they all have and incurrent and excurrent canal which assist in water movement Sponge Taxonomy Sponges have three main classes which are as followed Class Calcarea Calcareous Class Hexactinellida Glass sponges Class Demosponge Demosponge Class Calcarea Class calcarea sponges can be either asconoid syconoid or leuconoid There skeleton is composed of calcite spicules which are mostly unfused They contain either monaxons triaxons and tetraxons The words monoaxons describe the type of spicules and their sizes Mono being one tri being three and tetra meaning four spicule dissections Class Demospongiae Class Demospongiae represents represents nearly 80 990 of all sponge species including freshwater species They are commonly always leuconoid Demospongiae has spongin which is an elastic spongy collagen like sponging Their skeletons are made up of siliceous spicules they re never calcareous sponging spicules or mesohyl Demospongiae are the most diverse of sponges and have diverse sizes Demospongiae Diversity Bath Sponges No spicules Spongia sp Encrusting Sponge Have growths on the surface Vase sponge Have no symmetry Boring sponge Bores into the calcareous material Cliona sp Class Hexactinellida Their body walls are syncytial They also don t have a pinacoderm or choanoderm The collar body chambers are lined with choanosyncytium which have individual collar bodies They can be syconoid or leuconoid Their spicules are six rayed siliceous spicules called hexactines Feeding and Nutrition Most all sponges are efficient filter feeders except a few which a discussed later Sponges can pump a volume of water equal to their body volume once every five seconds The current is produced by the beating of the choanocytes flagella When it comes to nutrition the sponges are unicellular plankton and eat on small organic debris Cladorhizidae Carnivorous Desmosponges These are one species of sponges that aren t filter feeders They inhabit deep seas or caves They enjoy oligotrophic environments Oligotrophic means locations that has low levels of plant nutrients but has an abundance of oxygen in deeper parts They feed mostly on small crustaceans for example shrimp The capture their prey with their filaments with hook like spicules and they have no ostia oscula or choanocytes The sponges migrate towards their prey and then they engulf them They digest their food using extracellular digestion Bioactive Metabolites Many sponges have chemical defenses secondary metabolites to assist in deference towards their prey Desmosponges are the most utilized and studies sponge for pharmaceutical purposes Some metabolites might not be produced by the sponges but by their microbial symbionts Sponge Natural Products The notes cover three main sponges used for pharmaceutical purposes Halichondria okadai Spongia sp Discoderma dissoluta Found in Japan Inhibit tubulin Is a source of Inhibit microtubule assembly Is a source of halichondrins cytotoxins toxins to certain cells towards some types of leukemia and melanoma polymerization Is a source of spongistatins which are cytotoxic towards types of lung brain and colon cancers as well as melanoma discodermolide which is cytotoxic towards immunosuppressive properties Bioerosion Bioerosion is the erosion of materials by biological means Species of the Family Clionidae break down calcareous shells and coralline rocks This is done by the formation of a network of tunnels in