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Arctotherium Bonairense
''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. 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 faced bears) and ''Tremarctos'' (the Floridian and modern spectacled bear). Tremarctinae originate with their common ancestor, ''Plionarctos,'' in the Middle Hemphillian (earliest Late Miocene, ~10 Ma) of North America; ''Plionarctos'' is last recorded in the early Blancan (Early Pliocene, ~3.3 Ma). Around the Miocene-Pliocene boundary (~5 Ma) Tremarctines, along with other ursids, experienced an explosive radiation in diversity, as C4 vegetation (grasses) and open habitats dominated, the wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58See the 2014 version of the ICS geologic time scale million years ago (Ma). It is the second and most recent epoch of the Neogene Period in the Cenozoic, Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch. Prior to the 2009 revision of the geologic time scale, which placed the four most recent major glaciations entirely within the Pleistocene, the Pliocene also included the Gelasian Stage, which lasted from 2.59 to 1.81 Ma, and is now included in the Pleistocene. As with other older geologic periods, the Stratum, geological strata that define the start and end are well-identified but the exact dates of the start a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectacled Bear
The spectacled bear (''Tremarctos ornatus''), also known as the South American bear, Andean bear, Andean short-faced bear or mountain bear and locally as jukumari ( Aymara and Quechua), ukumari ( Quechua) or ukuku, is a species of bear native to the Andes Mountains in northern and western South America. It is the only living species of bear native to South America, and the last remaining short-faced bear (subfamily Tremarctinae). Unlike other omnivorous bears, the diet of the spectacled bear is mostly herbivorous. The species is classified as Vulnerable by the IUCN because of habitat loss. Taxonomy ''Tremarctos ornatus'' is commonly referred to in English as the "spectacled bear", a reference to the light colouring on its chest, neck and face, which may resemble spectacles in some individuals, or the "Andean bear" for its distribution along the Andes. The root ''trem''- comes from a Greek word meaning "hole"; ''arctos'' is the Greek word for "bear". ''Tremarctos'' is a refere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ursinae
Ursinae is a subfamily of Ursidae (bears) named by Swainson (1835). It was assigned to Ursidae by Bjork (1970), Hunt (1998), and Jin et al. (2007). Classification The genera '' Melursus'' and '' Helarctos'' are sometimes also included in ''Ursus''. The Asiatic black bear and the polar bear used to be placed in their own genera, ''Selenarctos'' and ''Thalarctos''; these are now placed at subgenus rank. * Subfamily Ursinae Fischer de Waldheim, 1817 ** †'' Aurorarctos'' Jiangzuo & Flynn, 2020 *** †''Aurorarctos tirawa'' Jiangzuo & Flynn, 2020 ** '' Helarctos'' Horsfield, 1825 *** ''Helarctos malayanus'' ( Raffles, 1821) – sun bear *** †'' Helarctos sinomalayanus'' (Thenius, 1947) ** '' Melursus'' Meyer, 1793 ***''Melursus ursinus'' ( Shaw, 1791) – sloth bear *** †'' Melursus theobaldi'' ( Lydekker, 1884) ** †'' Protarctos'' Kretzoi, 1945 *** †''Protarctos abstrusus'' (Bjork, 1970) *** †''Protarctos boeckhi'' ( Schlosser, 1899) *** †''Protarctos ruscinens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ailuropodinae
Ailuropodinae is a subfamily of Ursidae that contains only one extant species, the giant panda (''Ailuropoda melanoleuca'') of China. The fossil record of this group has shown that various species of pandas were more widespread across the Holarctic, with species found in places such as Europe, much of Asia, North America and even Africa. The earliest pandas were not unlike other modern bear species in that they had an omnivorous diet but by around 2.4 million years ago, pandas had evolved to be more herbivorous. The giant panda (''Ailuropoda'') belongs to the order of Carnivora, this means that the macronutrients that are digested are most similar to those of carnivores than to that of herbivores even though their diet consists mainly of bamboo. Systematics Ever since the giant panda was first described to science, they have been a source of taxonomic confusion, having been variously classified as a member of Procyonidae, Ursidae, Ailuridae, or even their own family Ailuropo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ursavinae
Ursavini is an extinct tribe of mammals of the family Ursidae (bears) endemic to North America, Europe, Africa, and Asia during the Miocene through the Pliocene, living from about 23—2.5 Mya, existing for roughly 20.5 million years. Ursavini was assigned to the Ursinae by Hunt (1998) and Jin et al. (2007) and includes the genera '' Agriotherium'' and '' Ursavus''.C. Jin, R. L. Ciochon, W. Dong, R. M. Hunt, Jr., J. Liu, M. Jaeger, and Q. Zhu. 2007. The first skull of the earliest giant panda. Proceedings of the National Academy of Sciences 104:10932-10937 However in a 2014 paper published on the origins of bear Bears are carnivoran mammals of the family (biology), 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 ...s, found ''Agriotherium'' to be closer to extant bears and some species of ''Ursavus'' might warrant to be in a separat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemicyoninae
Hemicyoninae is an extinct subfamily of Ursidae, often called dog bears (literally "half dog" (Ancient Greek, Greek: )). They were bear-like carnivorans living in Europe, North America, Africa and Asia during the Oligocene through Miocene epochs 33.9–5.3 Annum, Ma, existing for approximately . They are sometimes classified as a separate family (biology), family. Systematics The hemicyonines consists of three tribes: the Cephalogalini, Phoberocyonini, and Hemicyonini. In the past the hemicyonines were evaluated into family level (Hemicyonidae). However the vast majority of papers and researchers that cover the evolution of bears often classified them as an extinct subfamily of ursids or stem-bears. The genus ''Agriotherium'' was once classified as a hemicyonine but recent work has shown the genus is a crown-ursid. * Subfamily †Hemicyoninae Frick, 1926 ** Tribe †Cephalogalini de Bonis, 2013 *** †''Adelpharctos'' de Bonis, 1971 **** †''Adelpharctos ginsburgi'' de Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poaceae
Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, 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, including staple foods from domesticated cereal crops such as maize, wheat, rice, oats, barley, and millet for people and 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); oth ... [...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 1960s discovery by Marshall Davidson Hatch and Charles Roger Slack. 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. RuBisCO oxygenation gives rise to phosphoglycolate, which is toxic and requires the expenditure of energy to recycle through photorespiration. photosynthesis reduces photorespiration by concentrating around RuBisCO. To enable RuBisCO to work in a cellular environment where there is a lot of carbon dioxide and very little oxygen, leaves generally contain two partially isolated compartments called mesophyll cells and bundle-sheath cells. is initially fixed in the mesophyll cells in a reaction catalysed by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bear
Bears are carnivoran mammals of the family (biology), 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 most of the Northern Hemisphere and partially in the Southern Hemisphere. Bears are found on the continents of North America, South America, and Eurasia. 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 is mostly herbivorous, the remaining six species are omnivorous with varying diets. With the exception of courtship display, courting individuals and mothers with their young, bears are typically solitary animals. They may be diurnality, diurnal or nocturnal and have an excellent sense of smell. Despite their heavy build and awk ... [...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 th ... [...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 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 Epoch and end by the early . The Blancan is preceded by the Hemphil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
