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South American Short-faced Bear
''Arctotherium'' ("''bear beast''") is an extinct genus of the Pleistocene short-faced bears endemic to Central and South America. ''Arctotherium'' migrated from North America to South America during the Great American Interchange, following the formation of the Isthmus of Panama during the late Pliocene. The genus consists of one early giant form, ''A. angustidens'', and several succeeding smaller species, which were within the size range of modern bears. ''Arctotherium'' was adapted to open and mixed habitat. They are genetically closer to the spectacled bear (''Tremarctos ornatus''), than to ''Arctodus'' of North America, implying the two extinct forms evolved large size in a convergent manner, perhaps to facilitate dominating other carnivores in the competition for the biggest carcasses. Evolution Tremarctinae ''Arctotherium'' is part of the Tremarctinae subfamily of bears, otherwise known as the short faced bears, which also includes ''Arctodus'' (North American short ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58See the 2014 version of the ICS geologic time scale million years ago. It is the second and most recent epoch of the Neogene Period in the . The Pliocene follows the Epoch and is followed by the Epoch. Prior to the 2009 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poaceae
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns and pasture. The latter are commonly referred to collectively as grass. With around 780 genera and around 12,000 species, the Poaceae is the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae. The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, wheat, rice, barley, and millet as well as feed for meat-producing animals. They provide, through direct human consumption, just over one-half (51%) of all dietary energy; rice provides 20%, wheat supplies 20%, maize (corn) 5.5%, and other grains 6%. Some members of the Poaceae are used as building materials (bamboo, thatch, and straw); others can provide a source of biofuel, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C4 Carbon Fixation
carbon fixation or the Hatch–Slack pathway is one of three known photosynthetic processes of carbon fixation in plants. It owes the names to the 1960's discovery by Marshall Davidson Hatch and Charles Roger Slack that some plants, when supplied with 14, incorporate the 14C label into four-carbon molecules first. fixation is an addition to the ancestral and more common carbon fixation. The main carboxylating enzyme in photosynthesis is called RuBisCO, which catalyses two distinct reactions using either (carboxylation) or oxygen (oxygenation) as a substrate. The latter process, oxygenation, gives rise to the wasteful process of photorespiration. photosynthesis reduces photorespiration by concentrating around RuBisCO. To ensure that RuBisCO works in an environment where there is a lot of carbon dioxide and very little oxygen, leaves generally differentiate two partially isolated compartments called mesophyll cells and bundle-sheath cells. is initially fixed in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bear
Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Northern Hemisphere and partially in the Southern Hemisphere. Bears are found on the continents of North America, South America, Europe, and Asia. Common characteristics of modern bears include large bodies with stocky legs, long snouts, small rounded ears, shaggy hair, plantigrade paws with five nonretractile claws, and short tails. While the polar bear is mostly carnivorous, and the giant panda feeds almost entirely on bamboo, the remaining six species are omnivorous with varied diets. With the exception of courting individuals and mothers with their young, bears are typically solitary animals. They may be diurnal or nocturnal and have an excellent sense of smell. Despite their heavy build and awkward gait, they are adept runners, cli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zanclean
The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 Ma (million years ago) and 3.6 ± 0.005 Ma. It is preceded by the Messinian Age of the Miocene Epoch, and followed by the Piacenzian Age. The Zanclean can be correlated with regionally used stages, such as the Opoitian of New Zealand, and the Tabianian or Dacian of Central Europe. It also corresponds to the late Hemphillian to mid-Blancan North American Land Mammal Ages. In California, the Zanclean roughly corresponds to the middle part of the Delmontian stage. Definition The Zanclean Stage was introduced by Giuseppe Seguenza in 1868. It is named after ''Zancle'', the pre-Roman name for the Italian city of Messina on Sicily. The base of the Zanclean (and the Pliocene Series) lies with the top of magnetic chronozone Cr3 (about 100,000 years before the Thvera normal subchronozone C3n.4n). The base is also close to the extinction level of the calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blancan
The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 4,750,000 to 1,806,000 years Before Present, BP, a period of . Blancan North American Stage GeoWhen Database. Version 1.1.0. Retrieved 2017-June-26. It is usually considered to start in the early-mid Pliocene Epoch and end by the early Pleistocene. The Blancan is preceded by the Hemphillian and followed by the Irvingtonian NALMA stages. As usually defined, it corresponds to the mid-Zanclean through Piacenzian and Gelasian stages in Europe and Asia. In California, the Blancan roughly corresponds to the mid-Delmontian through Repettian and Venturian to the very early Wheelerian. The Austr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Miocene
The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million years ago) to 5.333 Ma. The evolution of life The gibbons (family Hylobatidae) and orangutans (genus ''Pongo'') are the first groups to split from the line leading to the hominins, including humans, then gorillas (genus ''Gorilla''), and finally, chimpanzees and bonobos (genus ''Pan (genus), Pan''). The splitting date between hominin and chimpanzee lineages is placed by some between 4 to 8 million years ago, that is, during the Late Miocene. References External links GeoWhen Database - Late Miocene Miocene, .03 Miocene geochronology, 03 Messinian, * Tortonian, * {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemphillian NALMA stages.
The Hemphillian can be further divided into the substages of:
*Late/Upper Hemphillian: Lower boundary source of the base of the Hemphillian (approximate).
*late Early Hemphillian: Lower boundary source of the base of the Hemphillian (approximate). Upper boundary source: base of Blancan (approximat ...
The Hemphillian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 10,300,000 to 4,900,000 years BP. It is usually considered to overlap the Tortonian age of the Late Miocene and Zanclean age of the Early Pliocene. The Hemphillian is preceded by the Clarendonian and followed by the Blancan The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 4,750,000 to 1,806,000 years Before Present, BP, a period of . [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plionarctos
''Plionarctos'' is an extinct genus of bear endemic to North America from the Miocene to the Pliocene, ~10.3—3.3 Mya (unit), Mya, existing for about 7 million years. ''Indarctos'' (10.7—9.2 Mya) preceded ''Plionarctos'' by only a few thousand years and was a contemporary of that bear and shared its habitat. ''Plionarctos'' preceded and was also contemporary with ''Tremarctos floridanus'' (4.9 million — 11,000 years ago) and shared its habitat. ''Plionarctos'' is the oldest known genus within the subfamily of the short-faced bears (Tremarctinae), and is believed to be ancestral to the clade. Fossil distribution Sites and specimen ages: *Ile de Ratonneau Breccia, Provence, France about ~800,000—100,000 years ago *Fort Green Mine, Polk County, Florida paleontological sites about 10.3—4.9 Mya *Taunton site, Adams County, Washington ''(P. harroldorum)'' about 4.9—1.8 Mya (''Plionarctos harroldorum'') *Pipe Creek Sinkhole, Grant County, Indiana ''(P. edensis)'' about 10.3â ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tremarctos Floridanus
''Tremarctos floridanus'', occasionally called the Florida spectacled bear, Florida cave bear, or rarely Florida short-faced bear, is an extinct species of bear in the family Ursidae, subfamily Tremarctinae. ''T. floridanus'' was widespread in the southeastern United States during the Rancholabrean epoch (250,000–11,000 years ago), with scattered reports of fossils from other parts of North America and from earlier epochs. Environment ''T. floridanus'' was widely distributed south of the continental ice sheet, along the Gulf Coast through Florida, north to Tennessee and South Carolina during the Rancholabrean epoch (250,000–11,000 years ago). A few fossil specimens have been reported from the Irvingtonian (2.5 million–250,000 years ago) and Blancan (4.75–1.8 million years ago) epochs in western North America. Fossils of ''T. floridanus'' have been reported from two sites in Belize. ''Arctodus'' (3 million–11,000 years ago) was a contemporary and shared its habitat with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tremarctos
''Tremarctos'' is a genus of the bear subfamily Tremarctinae, endemic to Americas from the Pliocene to recent. The northern species, the Florida short-faced bear, became extinct 11,000 years ago.B. Kurten & E. Anderson (1980): Pleistocene mammals of North America, pp 1-442. Columbia University Press The sole living ''Tremarctos'' species is the South American spectacled bear. Species * †''Tremarctos floridanus ''Tremarctos floridanus'', occasionally called the Florida spectacled bear, Florida cave bear, or rarely Florida short-faced bear, is an extinct species of bear in the family Ursidae, subfamily Tremarctinae. ''T. floridanus'' was widespread in ...'' - Florida short-faced bear * '' Tremarctos ornatus'' - spectacled bear References Bears Mammal genera Mammal genera with one living species Taxa named by Paul Gervais Extant Pliocene first appearances Fossil taxa described in 1855 {{carnivora-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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