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Phylum Porifera. Sponges. Basic fun facts. Adult sponges are sessile (they are attached to a surface) There are over 5000 species of sponges. Most are marine but some are found in fresh water.
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Phylum Porifera Sponges
Basic fun facts • Adult sponges are sessile (they are attached to a surface) • There are over 5000 species of sponges. • Most are marine but some are found in fresh water. • They are the simplest animal to have cells specialized to do tasks but they do not form true tissues. • Some sponges make poisonous toxins. We use these to research new medicines. • We use the skeletons of sponges to help us clean.
symmetry of the sponges • Sponge classification is difficult because shapes are so variable appearance can not be used reliably for identification. • They are asymmetrical (have no symmetry).
Cellular Structure of Sponges • There are two basic cells that make up a sponge: • Choanocytes (or collar cells): Line the inner canals of the sponge. Have flagella that used used to move the water through. • Amoebocytes: (or archaeocyte )These are mobile cells that travel through the sponges body wall. They carry nutrients , create spicules, and sexually reproduce. • Pinacocyte: Cells that make up the outer epidermis • Porocyte: Cells on surface with pores
Pictures taken from: http://io.uwinnipeg.ca/~simmons/Chap3298/img013.jpg
Skeletal Structure of Sponges. • The framework of the sponge is provided by spicules and spongin. • Spicules come in a variety if shapes and sizes. • Spicules are made of calcium carbonate or silica • Spongin: fibrous proteins that help support
The anatomy of the sponge The sponge is made of two distinct cell layers that are separated by a space filled with Spicules, Spongin and amebocytes. This space is called the mesenchyme or mesohyl. • The outer layer of cells is called the epidermis. It is made of pinacocyte and porocyte cells. • The inner layer of Choanocytes have flagella (whip like structures that are used to move the water) • There are small pores in the sponge called Ostia. • The central space in a sponge is called the spongocoel • The space where water exits the cell is called the Osculum (oscula plural) (there can be many)
Pictures taken from: http://io.uwinnipeg.ca/~simmons/Chap3298/img013.jpg
Structure Related to the Function • The spongin and spicules give the sponge shape • The collar cells with moving flagella create a lower water pressure inside the sponge. • The water with oxygen and nutrients enters through the ostia and flows into the oscula. • Nutrients and oxygen is absorbed by the cells. • To see a digram go to • www.enchantedlearning.com/subjects/invertebrates/sponge
Reproduction • The sponges can reproduce sexually or asexually. • Sexual: The sponges are hermaphroditic (have both sex cells in one sponge. Most reproduction is internal but some sex cells can float to other sponges. • Asexual: some sponges can slough or break of pieces that float in currents to new locations.
Sponges and the Environment • Sponges filter the water and are helpful in purifying the water. • Sponges are particularly important in coral reefs. • Scientists are interested in their ability to reduce nitrogen levels in reefs.