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Porifera

(Phylum)

Overview

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The sponges. Non-mobile animals consisting of many cells but built on a different plan from the Metazoa and are hence grouped separately. They have no nervous system and posses collar cells (choanocytes). Currents of water are drawn into the body through small pores (ostia) and passed out through larger pores (oscula), food particles being collected in the process. In most sponges the body is supported by a skeleton of calcium carbonate, silica or spongin.

Multicellular organisms containing a system of chambers and passageways that allow water to circulate constantly through the body. In many species, body size and shape is highly variable. Many sponges have a skeleton consisting of either calcium carbonate, silicon dioxide, or collagen fibers, or a combination of these substances. Sponges can reproduce sexually or asexually. In sexual reproduction, a larva called a parenchymula often develops in the sponge and swims out to live freely for a day or two before settling to the substrate. Sponges are suspension feeders, creating currents that draw in plankton and organic detritus from the water column.

Photos

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Taxonomy

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The Phylum Porifera is a member of the Superphylum Eutrochozoa. Here is the complete "parentage" of Porifera:

The Phylum Porifera is further organized into finer groupings including:

Classes

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Archaeocyatha

The Archaeocyatha or archaeocyathids ("ancient cups") were sessile, reef-building marine organisms of warm tropical and subtropical waters that lived during the early (lower) Cambrian period. It is believed that the centre of the Archaeocyatha origin is in East Siberia, where they are first known from the beginning of the Tommotian Age of the Cambrian, 525 million years ago (mya). In other regions of the world, they appeared much later, during the Atdabanian, and quickly diversified into over a hundred families. They became the planet's very first reef-building animals and are an index fossil for the Lower Cambrian worldwide. [more]

Calcarea

The calcareous sponges of class Calcarea are members of the animal phylum Porifera, the cellular sponges. They are characterized by spicules made out of calcium carbonate in the form of calcite or aragonite. While the spicules in most species have three points, in some species they have either two or four points. [more]

Demospongea

The Demospongiae are the largest class in the phylum Porifera. Their "skeletons" are made of spicules consisting of fibers of the protein spongin, the mineral silica, or both. Where spicules of silica are present, they have a different shape from those in the otherwise similar glass sponges. The demosponges include 90% of all species of sponges and are predominantly leuconoid in structure. [more]

Demospongiae

The Demospongiae are the largest class in the phylum Porifera. Their "skeletons" are made of spicules consisting of fibers of the protein spongin, the mineral silica, or both. Where spicules of silica are present, they have a different shape from those in the otherwise similar glass sponges. The demosponges include 90% of all species of sponges and are predominantly leuconoid in structure. [more]

Hexactinellida

Hexactinellid sponges are sponges with a skeleton made of four- and/or six-pointed siliceous spicules, often referred to as glass sponges. They are usually classified along with other sponges in the phylum Porifera, but some researchers consider them sufficiently distinct to deserve their own phylum, Symplasma. [more]

Hyalospongea

[more]

Irregulares

[more]

Regulares

The Fuerzas Regulares Ind?genas ("Indigenous Regular Forces"), known simply as the Regulares (Regulars), were the volunteer infantry and cavalry units of the Spanish Army recruited in Spanish Morocco. They consisted of Moroccans officered by Spaniards. These Moroccan troops played a major role in the Spanish Civil War (1936?39). [more]

Stromatoporoidea

More info about the Class Stromatoporoidea may be found here.

Sources

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Last Revised: October 03, 2013
2013/10/03 15:48:30