Porifera

=Phylum Porifera (meaning "pore bearer") = Animals in the Phyla Porifera are commonly referred to as **Sponges.** Sponges are a diverse group of sometimes common types, with about 5000 species known across the world. Sponges are primarily marine, but around 150 species live in fresh water. Sponges have cellular-level organization, meaning that that their cells are specialized so that different cells perform different functions, but similar cells are not organized into tissues and bodies are a sort of loose aggregation of different kinds of cells. This is the simplest kind of cellular organization found among parazoans.

Other characteristics of sponges include a system of pores (also called ostia) and canals, through which water passes. Water movement is driven by the beating of flagellae, which are located on specialized cells called choanocytes (collar cells). Sponges are either radially symmetrical or asymmetrical. They are supported by a skeleton made up of the protein collagen and spicules, which may be calcareous or siliceous, depending on the group of sponges examined. Skeletal elements, choanocytes, and other cells are imbedded in a gelatinous matrix called mesohyl or mesoglea. Sponges capture food (detritus particles, plankton, bacteria) that is brought close by water currents created by the choanocytes. Food items are taken into individual cells by phagocytosis, and digestion occurs within individual cells.

Reproduction by sponges is by both sexual and asexual means. Asexual reproduction is by means of external buds. Some species also form internal buds, called gemmules, which can survive extremely unfavorable conditions that cause the rest of the sponge to die. Sexual reproduction takes place in the mesohyl. Male gametes are released into the water by a sponge and taken into the pore systems of its neighbors in the same way as food items. Spermatozoa are "captured" by collar cells, which then lose their collars and transform into specialized, amoeba-like cells that carry the spermatozoa to the eggs.

The **Classes of Porifera** are based on the type of spicules produced and body organization. //**Calcarea**// - spicules of calcium;small, shallow ocean forms. //**Hexactinellida**// - glass sponges;6-ray silicon spicules; deep ocean forms. //**Demospongiae**// - simple silicon spicules,95% of all sponges; all depths of oceans; 150 freshwater forms //**Sclerospongiae**// - silicon and calcium skeleton; few types in deep, hidden ocean bottoms; hard like corals.

**Student ZooKeeper Pages of Species: (Enter Your Species Pages Below)**
Haliclona Urceolus(Zookeeper: Sidney Baker) Red Beard Sponge (Zookeeper: Taylor Cebuly) Elephant Ear Sponge (Zookeeper: Kenzie Davidson) Purple Encrusting Sponge (Zookeeper: Shaiann Etwara) Orange Puffball Sponge (Zookeeper: Erin Holbert) Birds Nest Sponge (Zookeeper: Syed Islam) Yellow Tube Sponge (Zookeeper: Marissa Jenkins) Venus Flower Basket (Zookeeper: Hannah Jones) //Chalinula nematifera// (Zookeeper: James K. Kanthachack) Glass Sponge (Zookeeper: Savannah Kelley) Spongilla argyrosperma (Zookeeper: Tori Lopez) Finger Goblet Glass Sponge (Zookeeper Whopper) Dead Mans Finger Sponge (Zookeeper: Heath McGregor) Spiny Tennis Ball Sponge (Zookeeper: Lindsey Rafus) Boring Sponge ( Zookeeper: Sarah Riemer) Red-Brown Branching Sponge (Zookeeper: Paco Rodriguez) Aggregated Vase Sponge (Zookeeper: Paige Ryder) Red Volcano Sponge (Zookeeper: Haley Shelton) Brown Tube Sponge (Zookeeper: Jeffrey Slape) Leuconia nivea (Zookeeper: Riley Stewart) Azure Vase Sponge (Zookeeper Rachel Tolliver) Branching Vase Sponge (Zookeeper: Ashley Veilleux) Blue Caribbean Sponge(Zookeeper: Jayme Willingham) Bread-Crumb Sponge (Zookeeper: Katie Woolen) Stove Pipe Sponge (Zookeeper: Elisabeth Young)

Myers, P. 2001. "Porifera" (On-line), Animal Diversity Web. Accessed March 06, 2011 http://animaldiversity.ummz.umich.edu/site/accounts/information/Porifera.html. http://www.sciencenewsforkids.org/articles/20090304/a1835_1585.jpg
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