MARB 435 Lecture 6 Outline of Last Lecture1. Writing Lab & Library Research Presentation2. Locomotion of Plankton3. Vertical Migration4. Continuous Plankton Recorder (CPR)5. Ocean Acidification6. Possible Effects of PlanktonOutline Current Lecture1. Phylum Porifera (Sponges) Introduction2. Sponge Cells & Body Wall Structures and Functions3. Sponge Tissues4. Levels of Complexity of Sponges5. Sponge Taxonomy6. Class Calcarea7. Class Demospongiaea. Demosponge Diversity8. Class Hexactinellida9. Feeding and Nutrition10. Cladorhizidae- Carnivorous demosponges11. Bioactive Metabolites12. Sponge Natural Products13. Bioerosion14. Sponge Symbionts15. Gemmules16. Sexual Reproduction17. Development18. Sponge Reefs19. Reef-Building Sponges20. ConservationCurrent Lecture Phylum PoriferaMainly 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 Functions1. Archaeocytes- Ameoboid cells which are essential in reproduction2. Pinacoderm- The outermost layer of cells in sponges3. Mesohyl- It’s a gelantenious matrix between the pinacoderm and choanoderm of sponges; commonly the middle layer4. Choanocyte- Cells that line the internal chambers of sponges5. Choanoderm- A layer of choanocytes and is the lower layer of sponges6. Sclerocyte- Is a type of spicule found in sponges7. Spicules- Tiny spike like structures found in the skeleton of sponges8. Pinocyte- A cell which undergoes pinocytosis which are fluids that that enter a cell by invagation9. Ostium- An opening into the sponges body cavity10. Porocyte- These are tubular cells that make up the pores of a spongeSponge TissueSponge’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 ComplexityThere are three levels of complexity for sponges, asconoid, syconoid and leuconid.- Asconoid- Simple sponges with a smooth body wall. They are simple base shapedwith 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 areato volume ration. Examples Haliclona sp., Cliona sp., and Aplysnia sp. they all have and incurrent and excurrent canal which assist in water movement.Sponge TaxonomySponges have three main classes which are as followed:- Class Calcarea- Calcareous- Class Hexactinellida- Glass sponges- Class Demosponge- DemospongeClass CalcareaClass calcarea sponges can be either asconoid, syconoid or leuconoid. There skeleton is composed of calcite spicules which are mostly unfused. They contain either monaxons, triaxonsand 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 DemospongiaeClass 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 HexactinellidaTheir 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 NutritionMost all sponges are efficient filter feeders except a few which a discussed later. Spongescan 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 DesmospongesThese 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 MetabolitesMany 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 ProductsThe 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 melanomapolymerization- Is a source of spongistatins which are cytotoxic towards types of lung, brain and colon cancers as well as melanomadiscodermolide which is cytotoxic towards immunosuppressive propertiesBioerosionBioerosion is the erosion of