Calcarea Hexactinellida Demospongiae The sponges or poriferans (from Latin porus "pore" and ferre "to bear") are animals of the phylum Porifera. They are primitive, sessile, mostly marine, waterdwelling filter feeders that pump water through their matrix to filter out particulates of food matter. Sponges are among the simplest of animals, with partially differentiated tissues but without muscles, nerves, or internal organs. In some ways they are closer to being cell colonies ...

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• Sponge - Anatomy
• Sponge - Taxonomy
• Sponge - Reproduction
• Sponge - Ecology
• Sponge - Skeleton as absorbent
• Sponge - Geological history

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Sponges comprise only four types of cells: Choanocytes (also known as "collar cells"), which line the spongocoel and function as the sponge's digestive system, are remarkably similar to the protistan choanoflagellates. Porocytes are tubular cells that make up the pores. Flat epidermal cells line the outside of the sponge and form its skin. Amoebocytes live between the choanocytes and the epidermis. They carry out many of the sponge's functions, such as transport of nutrients, secretion of the spicules, ...

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Sponge, Sponge - Anatomy, Sponge - Taxonomy, Sponge - Reproduction, Sponge - Ecology, Sponge - Skeleton as absorbent, Sponge - Geological history

Read more here: » Sponge: Encyclopedia II - Sponge - Anatomy

Modern sponges are predominantly marine, with some species adapted to freshwater environments, ranging from the inter-tidal zone to depths of 6,000 metres (19,680 feet). Certain types of sponges are limited in the range of depths at which they are found. Sponges are worldwide in their distribution, and range from waters of the polar regions to the tropical regions. Sponges are most abundant in both numbers of individuals and species in warmer waters. Their bodies are porous and they feed by filtering micro-organisms from the water. They lack any internal organs, a nervous system, or circulatory and digestive systems, such as are found i ...

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Sponge, Sponge - Anatomy, Sponge - Taxonomy, Sponge - Reproduction, Sponge - Ecology, Sponge - Skeleton as absorbent, Sponge - Geological history

Read more here: » Sponge: Encyclopedia II - Sponge - Ecology

Sponges are divided into classes based on the type of spicules in their skeleton. The three classes of sponges are bony (Calcarea), glass (Hexactenellida), spongin (Demospongiae). Some taxonomists have suggested a fourth class, Sclerospongiae, of coralline sponges, but the modern consensus is that coralline sponges have arisen several times and are not closely related.^{See also:}

Sponge, Sponge - Anatomy, Sponge - Taxonomy, Sponge - Reproduction, Sponge - Ecology, Sponge - Skeleton as absorbent, Sponge - Geological history

Read more here: » Sponge: Encyclopedia II - Sponge - Taxonomy