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Sponges
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. 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. 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 nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demospongiae
Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species worldwide (World Porifera Database). They are sponges with a soft body that covers a hard, often massive skeleton made of calcium carbonate, either aragonite or calcite. They are predominantly leuconoid in structure. 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. Some species, in particular from the Antarctic, obtain the silica for spicule building from the ingestion of siliceous diatoms. The many diverse orders in this class include all of the large sponges. Most are marine dwellers, but one order (Spongillida) live in freshwater environments. Some species are brightly colored, with great variety in body shape; the largest species are over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Some experts believe glass sponges are thlongest-lived animals on earth these scientists tentatively estimate a maximum age of up to 15,000 years. Biology Glass sponges are relatively uncommon and are mostly found at depths from below the sea level. Although the species '' Oopsacas minuta'' has been found in shallow water, others have been found much deeper. They are found in all oceans of the world, although they are particularly common in Antarctic and Northern Pacific waters. They are more-or-less cup-shaped animals, ranging from in height, with sturdy lattice-like internal skeletons made up of fused spicules of silica. The body is relatively symmetrical, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal Animal
Marine life, sea life, or ocean life is the plants, animals and other organisms that live in the salt water of seas or oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. Marine organisms, mostly microorganisms, produce oxygen and sequester carbon. Marine life in part shape and protect shorelines, and some marine organisms even help create new land (e.g. coral building reefs). Most life forms evolved initially in marine habitats. By volume, oceans provide about 90% of the living space on the planet. The earliest vertebrates appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians, which spend portions of their lives in water and portions on land. One group of amphibians evolved into reptiles and mammals and a few subsets of each returned to the ocean as sea snakes, sea turtles, seals, manatees, and whales. Plant forms such as kelp and other algae grow in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homoscleromorpha
Homosclerophorida is an order of marine sponges. It is the only order in the monotypic class Homoscleromorpha. The order is composed of two families: Plakinidae and Oscarellidae. Taxonomy Homoscleromorpha is phylogenetically well separated from Demospongiae. Therefore, it has been recognized as the fourth class of sponges. It has been suggested that Homoscleromorpha are more closely related to eumetazoans than to the other sponge groups, rendering sponges paraphyletic.Sperling, Pisani and Peterson 2007, cited in: The Cambrian Explosion p. 80, Erwin and Valentine 2013 This view has not been supported by later work using larger datasets and new techniques for phylogenetic inference, which tend to support sponges as monophyletic, with Homoscleromorpha grouping together with Calcarea. On the basis of molecular and morphological evidence, the two families Plakinidae and Oscarellidae have been reinstated. There are 117 species in this group divided into 9 genera. The spiculat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeocyatha
Archaeocyatha (or archaeocyathids 'ancient cups') is a taxon of extinct, sessile, reef-building marine sponges that lived in warm tropical and subtropical waters during the Cambrian Period. It is believed that the centre of the Archaeocyatha origin is now located 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. Preservation The remains of Archaeocyatha are mostly preserved as carbonate structures in a limestone matrix. This means that the fossils cannot be chemically or mechanically isolated, save for some specimens that have already eroded out of their matrices, and their morphology has to be determined from thin cuts of the stone in which th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placozoa
The Placozoa are a basal form of marine free-living (non-parasitic) multicellular organism. They are the simplest in structure of all animals. Three genera have been found: the classical ''Trichoplax adhaerens'', '' Hoilungia hongkongensis'', and '' Polyplacotoma mediterranea'', where the last appears most basal. The last two have been found only since 2017. Although the Placozoa were first discovered in 1883 by the German zoologist Franz Eilhard Schulze (1840–1921) and since the 1970s more systematically analyzed by the German protozoologist Karl Gottlieb Grell (1912–1994), a common name does not yet exist for the taxon; the scientific name means "flat animals". Biology ''Trichoplax'' is a small, flattened, animal around across. An amorphous multi-celled body, analogous to a single-celled ''Amoeba'', it has no regular outline, although the lower surface is somewhat concave, and the upper surface is always flattened. The body consists of an outer layer of simple epithel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aplysina Archeri
''Aplysina archeri'', also known as a stove-pipe sponge because of its shape, is a species of tube sponge that has long tube-like structures of cylindrical shape. Although they can grow in a single tube, they often grow in large groups of up to 22 tubes. A single tube can grow up to high and thick. These sponges mostly live in the Western Atlantic Ocean: the Caribbean, The Bahamas, Florida, and Bonaire. Like most sponges, they are filter feeders; they eat food such as plankton or suspended detritus as it passes them. Very little is known about their behavioral patterns except for their feeding ecology and reproductive biology. Tubes occur in varying colors including lavender, pink, gray, and brown. They reproduce both by asexual and sexual reproduction. These sponges take hundreds of years to grow and never stop growing until they die. Snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parazoa
Parazoa (Parazoa, gr. Παρα-, para, "next to", and ζωα, zoa, "animal") are a taxon with sub-kingdom category that is located at the base of the phylogenetic tree of the animal kingdom in opposition to the sub-kingdom Eumetazoa; they group together the most primitive forms, characterized by not having proper tissues or that, in any case, these tissues are only partially differentiated. They generally group a single phylum, Porifera, which lack muscles, nerves and internal organs, which in many cases resembles a cell colony rather than a multicellular organism itself. All other animals are eumetazoans, which do have differentiated tissues. On occasion, Parazoa reunites Porifera with Archaeocyatha, a group of extinct sponges sometimes considered a separate phylum. In other cases, Placozoa is included, depending on the authors. Porifera and Archaeocyatha Porifera and Archaeocyatha show similarities such as benthic and sessile habitat and the presence of pores, with diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stromatoporoidea
Stromatoporoidea is an extinct clade of sea sponges common in the fossil record from the Ordovician through the Devonian. They were especially abundant and important reef-formers in the Silurian and most of the Devonian.Stock, C.W. 2001, Stromatoporoidea, 1926–2000: ''Journal of Paleontology'', v. 75, p. 1079–1089. The group was previously thought to be related to the corals and placed in the phylum Cnidaria. They are now classified in the phylum Porifera, specifically the sclerosponges. There are numerous fossil forms with spherical, branching or encrusting skeletons of laminated calcite with vertical ''pillars'' between the ''laminae''. Specimen of its oldest genus, ''Priscastroma'', have been found within the Middle Ordovician Sediments. This same genus has been referred to as the species ''P. gemina'' Khrom., and is known to have been known to branch off into two forms, A and B. Form A gave rise to the genus ''Cystostroma'' while form B gave rise to the genus ''Labechia'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diploblast
Eumetazoa (), also known as diploblasts, Epitheliozoa, or Histozoa, are a proposed basal animal clade as a sister group of the Porifera (sponges). The basal eumetazoan clades are the Ctenophora and the ParaHoxozoa. Placozoa is now also seen as a eumetazoan in the ParaHoxozoa. Several other extinct or obscure life forms, such as ''Iotuba'' and ''Thectardis'', appear to have emerged in the group. Characteristics of eumetazoans include true tissues organized into germ layers, the presence of neurons and muscles, and an embryo that goes through a gastrula stage. Some phylogenists once speculated the sponges and eumetazoans evolved separately from different single-celled organisms, which would have meant that the animal kingdom does not form a clade (a complete grouping of all organisms descended from a common ancestor). However, genetic studies and some morphological characteristics, like the common presence of choanocytes, now unanimously support a common origin. Tradition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Edmund Grant
Robert Edmond Grant MD FRCPEd FRS FRSE FZS FGS (11 November 1793 – 23 August 1874) was a British anatomist and zoologist. Life Grant was born at Argyll Square in Edinburgh (demolished to create Chambers Street), the son of Alexander Grant WS, and his wife, Jane Edmond. He was educated at the High School in Edinburgh then studied Medicine at Edinburgh University. Having obtained his MD at Edinburgh in 1814, Grant gave up medical practice in favour of marine biology and the zoology of invertebrates, living on a legacy from his father. As a materialist and freethinker, and politically radical, he was open to ideas in biology that were considered subversive in the climate of opinion prevailing in Britain after the Napoleonic Wars. He cited Erasmus Darwin's ''Zoönomia'' in his doctoral dissertation, a work which introduced the idea of evolution in poetical form. In 1824 he was elected a Fellow of the Royal Society of Edinburgh his proposer being Dr John Barclay. He became ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nervous System
In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue first arose in wormlike organisms about 550 to 600 million years ago. In vertebrates it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body. Nerves that transmit signals from the brain are called motor nerves or '' efferent'' nerves, while those nerves that transmit information from the body to the CNS are called sensory nerves or '' afferent''. Spinal nerves are mixed nerves that serve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
