porifera n.
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  1. Porifera This project was done by… Rebecca Blankenship Jacob Collins Elizabeth Graves Christian Vauiso And Avery Waters

  2. Animals in the phylum Porifera (just sponges), are the simplest multicellular organisms on Earth. They can live in either salt or fresh water and are sessile for the first half of their life (polyp), free-living for the second (medusa). Sponges are invertebrates made up of a collection of cells. They do not have a circulatory system, a digestive system, or a nervous system. Sponges have a symmetric, irregular body that is made up of calcium carbonate, silica, or a protein called spongin.

  3. Filter Feeding Sponges are filter feeders. The sponge will draw in water through pores located throughout their body wall into a central cavity. The central cavity is lined with collar cells which have a ring of tentacles that surround the flagellum. Movement of the flagellum creates currents that keep the water flowing through the central cavity and out of a hole at the top of the sponge called the osculum. As water flows over the collar cells, food is captured by the collars ring of tentacles. Once absorbed, food is digested into the food vacuoles or transferred to the amoeboid cells in the middle layer of the wall for digestion. The water current also delivers a constant supply of oxygen to the sponge and removes nitrogenous waste products. Water exits the sponge through the osculum.

  4. Reproduction Sponges can reproduce asexually or sexually. Sponges are hermaphrodites, which means that either adult can act as the male or female in the reproduction process. Asexual reproduction happens when fragments the sponges body are broken off by water currents and carried to another location where the sponge will grow into a clone of its parent (identical DNA to the parent). Fertilization is internal for most species of sponge: some released sperm randomely float to another sponge down the water current. If a sperm is caught by another sponges collar cells (choanocytes), fertilization of the egg by the traveling sperm takes place inside the sponge. The resulting tiny larva is released and free-swimming (it uses cillia to propell itself through the water). The larva eventually settles on the ocean floor to spend its first half of life sessile, or attatched to the bottom of the ocean and grows into an adult.

  5. Examples There are three classes of sponges. Class Calcarea, Class Hexactinellida, and Class Demospongiae. Class Calcarea are chalk sponges that have calcareous spicules. These sponges are usually smaller than other sponges. Class Hexactinellida are glass sponges that have siliceous spicules. Class Demospongiae are horn sponges that have a skeleton of spongin or has no skeleton at all. These sponges can also grow to be the largest of sponges and the most vibrantly colored.

  6. CreditsEvanston, Illinois: McDougal Little, 2008…Animation brought to you by Avery WatersPower Point by Avery WatersPhotos and diagrams found by Avery Waters Information on slides brought to you by Rebecca Blankenship,Jacob Collins,Elizabeth Graves,and Christian Vauiso.Thank you for watching this Power point on the Phylum Porifera.