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Foraminiferida
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell (called a "test") of diverse forms and materials. Tests of chitin (found in some simple genera, and Textularia in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthic), while a smaller number float in the water column at various depths (i.e., are planktonic), which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA. Foraminifera typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in struc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Textulariida
The Textulariida are an order of foraminifera that produce agglutinated shells or tests. An agglutinated test is one made of foreign particles glued together with an organic or calcareous cement to form an external shell on the outside of the organism. Commonly, the order had been made up of all species of Foraminifera with these types of shells, but genetic studies indicate these organisms do not form an evolutionary group, and several superfamilies in the order have been moved to the order Allogromiida. The remaining forms are sometimes divided into three orders: the Trochamminida and Lituolida, which have organic cement, and the Textulariida ''sensu stricto'', which use a calcareous cement. All three orders or superfamilies are known as fossils from the Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the precedi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Involutinida
Involutinida is an order of foraminifera included in the Spirillinata found in the fossil record from the early Permian to early Late Cretaceous (Cenomanian). Diagnosis The Involutinida are characterized by a two chambered aragonitic test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film), ... consisting of an initial spheroidal chamber, or proloculus, enclosed by a tubular second, or main chamber. The test wall may be bilamellar (two layered), the inner layer being microgranular and often dark, the outer hyaline (ckear, glassy). Coiling may be planispiral or trochospiral, forming a cone. Lamellar thickenings or pillar-like structures may be found in the umbilical region on one ore both sides. Alfred R. Loeblich Jr & Helen Tappan,1988. Forminiferal Genera and their Classification. Van ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miliolida
The Miliolida are an order of foraminifera with calcareous, porcelacous tests that are imperforate and commonly have a pseudochitinous lining. Tests are composed of randomly oriented calcite needles that have a high proportion of magnesium along with organic material. Tests lack pores and generally have multiple chambers. Miliolids, which range from the Carboniferous to recent, are benthic Foraminifera abundant in shallow waters such as in estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ... and along coastlines, though they also include deepwater oceanic forms. The order Miliolida, sometimes referred to as a suborder, the Miliolina, is divided on the basis of differences in test morphology into five recognized superfamilies. References * External links * Tuboth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fusulinida
The Fusulinida is an extinct order within the Foraminifera in which the tests are traditionally considered to have been composed of microgranular calcite. Like all forams, they were single-celled organisms. In advanced forms the test wall was differentiated into two or more layers. Loeblich and Tappan, 1988, gives a range from the Lower Silurian to the Upper Permian, with the fusulinid foraminifera going extinct with the Permian–Triassic extinction event. While the latter is true, a more supported projected timespan is from the Mid-Carboniferous period. Taxonomy Thirteen superfamilies are presently recognised, based on taxa (families) included in the three superfamilies given in the Treatise. Three are based on families in the Parathuramminacea, 1964, and 2.9 million families in the Endothyracea, 1964. The Fusulinacea remains the same in both sources (Treatise 1964 and Loeblich and Tappan, 1988). The term fusulinata has traditionally been used to refer to all palaeozoic for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globigerinida
The Globigerinina is a suborder of foraminiferans that are found as marine plankton. They produce hyaline calcareous tests, and are known as fossils from the Jurassic period onwards. The group has included more than 100 genera and over 400 species, of which about 30 species are extant. One of the most important genera is ''Globigerina''; vast areas of the ocean floor are covered with ''Globigerina'' ooze (named by Murray and Renard in 1873), dominated by the shells of planktonic forms. Description Globigerinids are characterized by distinctly perforate planispiral or trochospiral tests composed of lamellar radial hyaline (glassy) calcite, with typically globular chambers and single interiomarginal aperture. Some however have multiple or auxiliary apertures, and in some the aperture is areal or terminal in location. Some, also, have keels, reinforcing thickenings along exterior angles. An adaptation to the planktonic habit is the development of long narrow spines that support ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotaliida
The Rotaliida are an order of Foraminifera, characterized by multilocular tests (shells) composed of bilamellar perforate hyaline lamellar calcite that may be optically radial or granular. In form, rotaliid tests are typically enrolled, but may be reduced to biserial or uniserial, or may be encrusting with proliferated chambers. Chambers may be simple or subdivided by secondary partitions; the surface is smooth, papillate, costate, striate, or cancellate; the aperture is simple or with an internal toothplate, entosolenian tube, or hemicylindrical structure; it may have an internal canal or stolen systems. Rotaliids are primarily oceanic benthos, although some are common in shallower estuarine waters. They also include many important fossils, such as the nummulitids. Taxonomy The Rotaliida are now divided into the following superfamilies: [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicoloculinida
''Miliamellus'' is a genus of Cenozoic benthic foraminifera with tests made of imperforate opaline silica. It is the only genus in the order Silicoloculinida and the family Silicoloculinidae. It is sometimes referred to by the junior synonym ''Silicoloculina''. The family Silicoloculinidae, named by Resig, ''et al.'', 1980, is characterized by tests that resemble those of the imperforate calcareous Miliolidae, or the finely agglutinated Rzehakinidae in which chambers are about half a coil in length and arranged in various planes. Resig et al. named the genus ''Silicoloculina'' for specimens recovered from below the carbonate compensation depth in the Scotia Sea The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean. It is bounded on the west by the Drake Passage and on the north, east, and south by the Scotia Arc, an undersea ridge and ... and the Peru-Chile Trench. Loeblich and Tappan synonymised thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagenida
Lagenida is an order of benthic foraminiferal protists in which the tests (shells) are monolamellar, with walls composed of optically and ultra-structurally radiate calcite, with the crystallographic c-axes perpendicular to the surface. Lagenids first appear in the Upper Silurian and continue to the Recent. They are currently divided into two superfamilies, the older Robuloidacea which range from the Upper Silurian to the Lower Cretaceous (Albian) and the younger Nodosariacea, ranging from the Permian to Recent. Taxonomic history Lagenida (suborder Lagenina in Loeblich and Tappan 1988) is an emendation of the rotaliid superfamily Nodosariacea, removing it from the Rotaliina in the ''Treatise on Invertebrate Paleontology'' (Loeblich and Tappan, 1964) and combining it with the Robuloidacea, named by Reiss, 1963, to form a new order Lagenida. Robuloidacea includes families previously included in the Fusulinida and found in either of the superfamilies Parathuramminacea and Endothy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirillinida
The Spirillinida are an order of foraminifera in which the test, or shell, primitively consists of an enrolled open tube, coming after the proloculus, wound planospirally or conically, commonly composed of an optically single crystal of calcite. The aperture is a simple opening at the end of the tube. Advanced forms with more than one chamber may consist of a few crystals, or rarely, a mosaic of crystals of calcite. The Spirillinida were separated from the Rotaliida The Rotaliida are an order of Foraminifera, characterized by multilocular tests (shells) composed of bilamellar perforate hyaline lamellar calcite that may be optically radial or granular. In form, rotaliid tests are typically enrolled, but ma ... where they had been included as the Spirillinacea. However, not only is the spirillinid test rather distinct from typical rotaliid tests commonly composed of radially laminated calcite, but so are the protists distinct. The gametes produced by spirillinids during sex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protist
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exclusion of other eukaryotes means that protists do not form a natural group, or clade. Therefore, some protists may be more closely related to animals, plants, or fungi than they are to other protists. However, like the groups ''algae'', ''invertebrates'', and '' protozoans'', the biological category ''protist'' is used for convenience. Others classify any unicellular eukaryotic microorganism as a protist. The study of protists is termed protistology. History The classification of a third kingdom separate from animals and plants was first proposed by John Hogg in 1860 as the kingdom Protoctista; in 1866 Ernst Haeckel also proposed a third kingdom Protista as "the kingdom of primitive forms". Originally these also included prokaryotes, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allogromiida
The Allogromiida is an order of single-chambered, mostly organic-walled foraminiferans, including some that produce agglutinated tests (Lagynacea). Genetic studies indicate that some foraminiferans with agglutinated tests, previously included in the Textulariida or as their own order Astrorhizida, may also belong here. Allogromiids produce relatively simple tests, usually with a single chamber, similar to those of other protists such as ''Gromia''. They are found as both marine and freshwater forms, and are the oldest forms known from the fossil record. Genus * ''Allogromia ''Allogromia'' is a genus of Foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm fo ...'' References * * * Further reading * Foraminifera orders Monothalamea Extant Cambrian first appearances {{foram-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectoplasm (cell Biology)
Ectoplasm (also exoplasm) (from the ancient Greek words ἐκτός (èktòs): ''outside'' and πλάσμα: ''plasma'', literally meaning: ''that which has form'') is the non-granulated outer part of a cell's cytoplasm, while endoplasm is its often granulated inner layer. It is clear, and protects as well as transports things within the cell. Moreover, large numbers of actin filaments frequently occur in the ectoplasm, which form an elastic support for the cell membrane. It contains actin and myosin microfilaments. See also * Cytoplasm * Endoplasm Endoplasm generally refers to the inner (often granulated), dense part of a cell's cytoplasm. This is opposed to the ectoplasm which is the outer (non-granulated) layer of the cytoplasm, which is typically watery and immediately adjacent to the ... References Cell anatomy {{cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
