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Fusulinids
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 fora ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fusulinid Limestone, Upper Pennsylvanian; Elk County KS
The Fusulinida is an extinct Order (biology), order within the Foraminifera in which the Foraminifera test, 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. Alfred R. Loeblich Jr, Loeblich and Helen Niña Tappan Loeblich, 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, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (cell biology), ectoplasm for catching food and other uses; and commonly an external shell (called a "Test (biology), 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 benthos, 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 (biology), test, or shell, which can have eithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraminifera Test
Foraminiferal tests are the tests (or shells) of Foraminifera. Foraminifera (''forams'' for short) are single-celled predatory protists, mostly marine, and usually protected with shells. These shells, often called tests, can be single-chambered or have multiple interconnected chambers; the cellular machinery is contained within the shell. So important is the test to the biology of foraminifera that it provides the scientific name of the group—''foraminifera'', Latin for "hole bearers", referring to the pores connecting chambers of the shell in the multi-chambered species. Foraminiferal tests are usually made of calcite, a form of calcium carbonate (), but are sometimes made of aragonite, agglutinated sediment particles, chitin, or (rarely) of silica. Other foraminifera lack tests altogether. Over 50,000 species are recognized, both living (6,700 - 10,000)Ald, S.M. ''et al.'' (2007Diversity, Nomenclature, and Taxonomy of Protists ''Syst. Biol.'' 56(4), 684–689, DOI: 10.1080/1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian–Triassic Extinction Event
The Permian–Triassic (P–T, P–Tr) extinction event, also known as the Latest Permian extinction event, the End-Permian Extinction and colloquially as the Great Dying, formed the boundary between the Permian and Triassic geologic periods, as well as between the Paleozoic and Mesozoic eras, approximately 251.9 million years ago. It is the Earth's most severe known extinction event, with the extinction of 57% of biological families, 83% of genera, 81% of marine species and 70% of terrestrial vertebrate species. It was the largest known mass extinction of insects. There is evidence for one to three distinct pulses, or phases, of extinction. The scientific consensus is that the main cause of extinction was the large amount of carbon dioxide emitted by the volcanic eruptions that created the Siberian Traps, which elevated global temperatures, and in the oceans led to widespread anoxia and acidification. Proposed contributing factors include: the emission of much addition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helen Niña Tappan Loeblich
Helen Niña Tappan Loeblich (October 12, 1917 – August 18, 2004) was an American micropaleontologist who was a professor of geology at the University of California, Los Angeles, a United States Geological Survey (USGS) biostratigrapher, and a scientific illustrator whose micropaleontology specialty was research on Cretaceous foraminifera. Early life Dr Helen Nina Tappan Leoblich was born on October 12, 1917, in Norman, Oklahoma. She came from a well-educated background. Her mother Mary Pearl Jenks Tappan was a math teacher at Cornell, and her father, Frank Girard Tappan, was a Dean of Electrical Engineering at the University of Oklahoma. Education Tappan Loeblich earned her BS in 1937 and her Master's in 1939, both in geology from the University of Oklahoma. Her master's thesis was on mid-Cretaceous foraminifera of Oklahoma and Texas. At the University of Oklahoma, she met her future husband and long time scientific collaborator, Alfred R. Loeblich Jr, in chemistr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the lowest measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where vegetation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone during ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globothalamea
Globothalamea comprises a class of multichambered foraminifera based in part on SSU rDNA evidence; the other is Tubothalamea. Six orders are included, which vary notably in composition, wall structure, and chamber arrangement. The Lituolida, Loftusiida, and Textulariida (as emended) have tests (shells) of agglutinated matter, glued together by various cements, but differ in chamber arrangement, wall structure, and complexity. In contrast the Carterinida, Robertinida and Rotaliida, with buliminids lumped into the Rotaliida, have calcareous tests. Those of rotaliid genera, which vary considerably, are of perforate hyaline (glassy) calcite. in contrast the Carterinida have tests composed of bundled calcite spicules. The Robertida differ in being composed, instead, of aragonite. [...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] |
