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Sponge

Sponges (also known as sea sponges), the members of the phylum Porifera[3] (/pəˈrɪfərəˌ pɔː-/ pər-IF-ər-ə, por-; meaning 'pore bearer'),[4] are a basal animal clade as a sister of the diploblasts.[5][6][7][8][9] They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells.

This article is about the phylum of aquatic animal. For the porous cleaning tool, see Sponge (tool). For other uses, see Sponge (disambiguation).

Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have complex nervous,[10] digestive or circulatory systems like humans. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Believed to be some of the most basal animals alive today, sponges were possibly the first to branch off the evolutionary tree from the last common ancestor of all animals, which would make them the sister group of all other animals.[5]


The branch of zoology that studies sponges is known as spongiology.[11]

Etymology

The term sponge derives from the Ancient Greek word σπόγγος spóngos.[12]

are amoeba-like cells that move slowly through the mesohyl and secrete collagen fibres.

Lophocytes

are another type of collagen-producing cell.

Collencytes

cells secrete polysaccharides that also form part of the mesohyl.

Rhabdiferous

and spermatocytes are reproductive cells.

Oocytes

secrete the mineralized spicules ("little spines") that form the skeletons of many sponges and in some species provide some defense against predators.

Sclerocytes

In addition to or instead of sclerocytes, have spongocytes that secrete a form of collagen that polymerizes into spongin, a thick fibrous material that stiffens the mesohyl.

demosponges

("muscle cells") conduct signals and cause parts of the animal to contract.

Myocytes

"Grey cells" act as sponges' equivalent of an .

immune system

(or amoebocytes) are amoeba-like cells that are totipotent, in other words, each is capable of transformation into any other type of cell. They also have important roles in feeding and in clearing debris that block the ostia.

Archaeocytes

Systematics

Taxonomy

Carl Linnaeus, who classified most kinds of sessile animals as belonging to the order Zoophyta in the class Vermes, mistakenly identified the genus Spongia as plants in the order Algae.[82] For a long time thereafter, sponges were assigned to subkingdom Parazoa ("beside the animals") separated from the Eumetazoa which formed the rest of the kingdom Animalia.[83] They have been regarded as a paraphyletic phylum, from which the higher animals have evolved.[84] Other research indicates Porifera is monophyletic.[85]


The phylum Porifera is further divided into classes mainly according to the composition of their skeletons:[20][32]

are most closely related to Eumetazoa;

Homoscleromorpha

calcareous sponges are the next closest;

the other demosponges are evolutionary "aunts" of these groups; and

the , bag-like animals whose fossils are found in Cambrian rocks, may be sponges.[110]

chancelloriids

Stephen Hillenburg

Lists of sponges

Sponge Reef Project

compounds found in marine Haplosclerida sponges

3-Alkylpyridinium

Flash animations of sponge body structures, water flow and feeding

Water flow and feeding in the phylum Porifera (sponges)

Information on the ecology and the biotechnological potential of sponges and their associated bacteria.

Carsten's Spongepage

Tarpon Springs, Florida

History of Tarpon Springs sponge industry

Nature's 'fibre optics' experts

The Sponge Reef Project

Queensland Museum information about sponges

Queensland Museum Sessile marine invertebrates collections

Queensland Museum Sessile marine invertebrates research

Archived 2008-12-08 at the Wayback Machine, Bernard Picton, Christine Morrow & Rob van Soest

Sponge Guide for Britain and Ireland

the world list of extant sponges, includes a searchable database.

World Porifera database

// Food and Agriculture Organisation

Sponges: World production and markets