Porifera are porous organisms that filter out water and other particles through various sizes of holes. In the phylum Porifera, there are about 8,000 different species, which are mostly marine. This phylum has many characteristics that make them unique. They do not have any organ systems, but instead they have highly specialized cells that do the same job. These organisms have totipotent cells, which means that they are capable of giving rise to any cell type.
By: Douglas Ericson
“Porifera and other filter feeders are crucial for the cycle of nutrients in these ecosystems. They take in nutrients that have been dissolved into the water column, from the seafloor or elsewhere. Additionally, poriferans take in organic matter from deceased organisms such as plankton.”
By: Alana Olendorf
“Sponges are typically harvested from the bottom of the ocean by divers. These divers will use either a specially designed hook or knife to do the harvesting. The divers will cut about 2/3 of the sponge off and keep it for harvesting, leaving the rest of the sponge to regrow. The divers will squeeze the gurry out of the harvested sponge and it will be taken back to the boat. On the boat the sponges are cleaned and left under a burlap sack in the sun. This method of harvesting sponges is much better than the original way that sponges were harvested.”
By: Jennifer Rosado
“Of the total anthropogenic carbon dioxide released into the atmosphere only half persists in the atmosphere, 20% is taken up by the earths biosphere and 30% is absorbed by the ocean. This number is believed to double in the next 50 years putting the marine life in danger.”
Class Descriptions By: Jessica Comeau
Skeletal composition is on of the main distinguishing feature between all Porifera species. Calcarea are sponges which possess spicule structures made of calcium carbonate. Found mainly in temperate areas, the small radially symmetrical Calcarea species can either present in the asconoid, syconoid, or leuconoid vase-like body form. The only asconoid body forms are found in the class Calcarea. These species may reproduce sexually or asexually. Calcarea produce coeloblastula larvae during reproduction that may develop into choanocytes, or the free swimming amphiblastula larvae form.
The Hextactinellida, also known as glass sponges, possess a skeleton composed of six-rayed siliceous spicules which create a sturdy mineral lattice. Glass sponges are mainly found at depths of 200-6000 meters and are cup-shaped organisms that have a syconoid or leuconoid body form. The distinguishing feature of Hextactinellida is the presence of an outer layer consisting of a single plasma membrane comprised of numerous nuclei. Due to this feature glass sponges do not have a pinacoderm layer and lack contractile elements.
Demospongiae are the largest class of Porifera, with nearly 80% of all living and extinct sponges being classified into this group. The skeletal structure of Demospongiae is comprised of spongin fibers or siliceous spicules, and nearly all of Demospongiae consist of a leuconoid body form. The Demospongiae species are some of the most brightly colored species displaying yellow, purple, red, or green pigments derived from the granules in amoebocytes. They can form thin encrustations, lumps, finger-like growths, or urn shapes.
Terms and Definitions
By: Simone McEwan
|Class Demospongiae: The most diverse class in the Porfera phylum. They include 90% of all species of sponges with nearly 7,000 species worldwide. They are predominantly leuconoid in structure.||Archeocytes: amoeboid cells found in sponges. They are totipotent and have varied functions depending on the species.|
|Class Calcarea: The class of calcareous sponges, Calcarea, includes 400, strictly marine species. Characterized by spicules made out of calcium carbonate in the form of calcite or aragonite.||Spicules (calcareous, siliceous): structural elements found in sponges that provide structural support and deter predators.|
|Class Hextactinellida: Hexactinellid sponges are sponges with a skeleton made of four- and/or six-pointed siliceous spicules, often referred to as glass sponges.||Spongin: the horny or fibrous substance found in the skeleton of many sponges.|
|Osculum (oscula): a large aperture in a sponge through which water is expelled.||Schlerocytes: specialised cells that secrete the mineralized structures in the body wall of some invertebrates.|
|Ostium (ostia): is a large neighbourhood in the X Municipio of the commune of Rome, Italy, near the ancient port of Rome, named Ostia, which is now a major archaeological site known as Ostia Antica.||Spongocytes: cells that are responsible for secretion of the perispicular spongin.|
|Spongocoel (atrium): is the large, central cavity of sponges. Water enters the spongocoel through hundreds of tiny pores and exits through the larger opening.||Gemmules: a tough-coated dormant cluster of embryonic cells produced by a freshwater sponge for development in more favorable conditions.|
|Choanocytes: a flagellated cell with a collar of protoplasm at the base of the flagellum, numbers of which line the internal chambers of sponges.||Totipotent: capable of giving rise to any cell type or (of a blastomere) a complete embryo.|
|Aquiferous system: an essential character of poriferans and supports their monophyly.||Asconoid: Sponge that has a tube or vase-like structure.|
|Pinacocytes: flattened cells containing many granules; capable of contracting.||Syconoid: a body form of medium complexity in sponges where the body wall has become folded and the choanocytes (flagellated collar cells) are not located along the spongocoel, but along radial canals.|
|Porocytes: tubular cells which make up the pores of a sponge known as ostia.||Leuconoid: the body form of highest complexity in sponges. The leucanoid form is highly irregular, displays the greatest degree of folding of the body wall, and has lost radial symmetry.|
|Mesohyl: formerly known as mesenchyme or as mesoglea, is the gelatinous matrix within a sponge.||Reaggregation: The ability of sponge cells to recognize each other and come to together.|
Terms and Definitions
By; Devon Audibert
Choanocytes: Cells specialized in sponges, use flagellum to allow water to enter the sponge through the ostium.
Aquaiferous system: Water circulatory system found in sponges, water in through ostium, out through osculum.
Pinacocytes: Flat cells that form the dermal layer in sponges.
Porocytes: Cells along the pores (ostium) that allow the water to flow into the central cavity of the sponge.
Mesohyl: The gelatinous matrix in a sponge, fills the space between the pinacoderm and the choanoderm.
Sclerosponges: Sponges which have a soft body that is used to cover a hard skeleton, usually made of calcium carbonate.
Archeocytes: Totipotent cells that work like organ systems within a sponge.
Spicules: Micro sized spike like structures that line the outside of some sponges, made up of calcium carbonate for the most part.
Spongin: A modified protein which is the main component in the sponges skeleton
Schlerocytes: Specialized cells that secrete spicules which are found on the outer layer of sponges.
Spongocytes: Cells that secrete spongin fibers inside of sponges.
Gemmules: Bubd on the inside of sponges which are used during asexual reproduction.
Totipotent: When something is totipotent, it can give rise to ANY CELL.
Asconoid: The tube, unique structure that sponges hold.
Syconoid: Body structure where the sponge folds and the choanocytes change location.
Leuconoid: Most complex body structure in sponges, water is selected to flow into sponge and pumping is increased due to increase of mesohyl.
Reaggregation: Cells in sponges come together and reform to create multicellular structures.
By: Marisa Benjamin
Group: Demospongiae/ Image Magnification: 10x
Orange Devil’s Finger