PORIFERA

1. PORIFERA http://www.insidesocal.com/tv/612~SpongeBob-SquarePants-Posters.jpg The best Porifera of all!  Period six By: Matt Figueroa and Paige Cornwell

2. What stays in one place, lives in the water, and eats minuscule organisms? • No, it's not a Venus's fly-trap with a scuba tank, it's the carnivorous sponge!

3. PORIFERA •   Porifera are also known as Sponges. • Sponges are among the oldest known animal fossils, dating from the late Precambrian. • About 5,000 species worldwide • About 25 species in freshwater • They have no organs or tissues; cells are somewhat independent. • composed of three distinct groups, the Hexactinellida (glass sponges), the Demospongiae, the Calcarea (calcareous sponges), and Sclerospongiae

4. Class Calcarea 1. These are calcareous sponges with spicules of calcium carbonate. 2. The spicules are straight or have three or four rays. 3. Most are small sponges with tubular or vase shapes. Spicules - A small needlelike structure or part, such as one of the silicate or calcium carbonate processes supporting the soft tissue of certain invertebrates, especially sponges. http://seanet.stanford.edu/Porifera/leucandr_hea580.jpg

5. Class Hexactinellida 1. These are glass sponges with six-rayed spicules of silica. 2. Most are radially symmetrical. 3. There are about 500 species. They occur mainly in deep, cold waters between 200 - 2000 m, although some can be found below 6000. http://tolweb.org/tree/ToLimages/staurocalyptus1.200a.jpg

6. Class Demospongiae 1. This class contains 95% of living sponge species. 2. Spicules are siliceous but not six rayed; they may be absent or bound together by spongin. 3. Demospongiae are often brightly coloured. 4. All are marine except for Spongillidae, the freshwater sponges. http://www.lvp.com/data/mso2007/SCUBA%20SPONGES.jpg

7. Class Sclerospongiae 1. Small group of sponges that resemble corals. 2. Found in dark tunnels in coral reefs. 3. The skeleton consists of siliceous spicules and spongin on a thick basal layer of calcium carbonate. 4. a soft body that covers a hard, often massive skeleton

8. Body Plan • No definite symmetry. • Body multicellular, few tissues, no organs. • Cells and tissues surround a water filled space but there is no true body cavity. • Often have a skeleton of spicules.

9. Feeding • Water flowing through sponges provides food and oxygen • In general, sponges feed by filtering bacteria from the water that passes through them. • Some sponges trap roughly 90 percent of all bacteria in the water they filter. • Harbor symbionts such as green algae, dinoflagellates, or cyanobacteria to derive nutrients. • Capture small crustaceans with their spicules which act like Velcro when they come in contact with the crustacean exoskeletons. • Cells then migrate around the helpless prey and digestion takes place extracellularly.

10. Respiration • Takes in water through its pores • in more advanced forms, with canals that move the water to all throughout the sponge • Oxygen from the water is diffused into the cells of the organism • Rates of respiration depend on the concentration of oxygen in the water • Respiration takes place extracellularly • Sponges have no respiratory organs

11. Circulation • Water is drawn into the sponge through a series of incurrent pores, or dermal ostia • Enters central cavity • Exits the sponge through a large opening at the top called the osculum • Rate of circulation depends on current of water • Oxygen and other nutrients diffuse into the cells as it passes through the body cavity

12. Excretion • Just as in respiration and circulation, excretion depends on the movement of water • Wastes such as ammonia and carbon dioxide are diffused into surrounding water • The water is then carried away due to current

13. Response • Sponges have no nervous or sense organs • Simplest contractile elements • Protects itself by producing toxins that make themselves poisonous to predators. • Interestingly, one of these is being tested to treat cancer (a Caribbean sponge)

14. Movement • Sponges are generally sessile • Meaning they do not physically move • The only movement observed in a sponge is the opening and closing of pores • Some observed to move up to 4mm per day within aquaria • May attach to organisms such as hermit crabs to use as transportation • Larvae of the sponges are free moving

15. Reproduction • Asexually • fragments that break off from the parent animal may become new sponges  • gemmules: collections of amoebocytes within a hard, protective outer layer • Sexual reproduction in sponges is highly specialized • External: the sperm and egg cells shed into the water • Internal: sperm cells are carried by the water currents out of the osculum of one sponge and into the interior cavity of another sponge • Most kinds of sponges are hermaphrodites

16. Works Cited • "Phylum Porifera: Sponges ." infusion.allconet.org. N.p., n.d. Web. 19 Apr 2010. <http://www.infusion.allconet.org/webquest/PhylumPorifera.html>. • "Porifera: Life History and Ecology ." ucmp.berkeley.edu. Berkeley, n.d. Web. 19 Apr 2010. <http://www.ucmp.berkeley.edu/porifera/poriferalh.html>. • Myers, P. 2001. "Porifera" (On-line), Animal Diversity Web. Accessed April 20, 2010 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Porifera.html. • Johnson, Raven. Biology. 6th. New York: McGraw Hill, 2002. 884-885. Print.