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American Black Bear
The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but will leave forests in search of food, and are sometimes attracted to human communities due to the immediate availability of food. The International Union for Conservation of Nature (IUCN) lists the American black bear as a least-concern species, due to its widespread distribution and a large population estimated to be twice that of all other bear species combined. Along with the brown bear (''Ursus arctos''), it is one of only two modern bear species not considered by the IUCN to be globally threatened with extinction. Taxonomy and evolution Despite living in North America, American black bears are n ... [...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 Cenozoic Era. The Pliocene follows the Epoch and is followed by the Epoch. Prior to the 2009 revision of the geologic time sca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Taxa
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxonomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the Quaternary glaciation. Individual pulses of cold climate within an ice age are termed '' glacial periods'' (or, alternatively, ''glacials, glaciations, glacial stages, stadials, stades'', or colloquially, ''ice ages''), and intermittent warm periods within an ice age are called '' interglacials'' or ''interstadials''. In glaciology, ''ice age'' implies the presence of extensive ice sheets in both northern and southern hemispheres. By this definition, Earth is currently in an interglacial period—the Holocene. The amount of anthropogenic greenhouse gases emitted into Earth's oceans and atmosphere is predicted to prevent the next glacial period for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary Glaciation
The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial and interglacial periods during the Quaternary period that began 2.58 Ma (million years ago) and is ongoing. Although geologists describe this entire period up to the present as an "ice age", in popular culture this term usually refers to the most recent glacial period, or to the Pleistocene epoch in general. Since Earth still has polar ice sheets, geologists consider the Quaternary glaciation to be ongoing, though currently in an interglacial period. During the Quaternary glaciation, ice sheets appeared, expanding during glacial periods and contracting during interglacial periods. Since the end of the last glacial period, only the Antarctic and Greenland ice sheets have survived, with other sheets formed during glacial periods, such as the Laurentide Ice Sheet, having completely melted. The major effects of the Quaternary glaciation have been the continental erosio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Generalist Species
A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different natural resource, resources (for example, a heterotroph with a varied diet (nutrition), diet). A specialist species can thrive only in a narrow range of environmental conditions or has a limited diet. Most organisms do not all fit neatly into either group, however. Some species are highly specialized (the most extreme case being monophagous, monophagy, eating one specific type of food), others less so, and some can tolerate many different environments. In other words, there is a continuum from highly specialized to broadly generalist species. Description Omnivores are usually generalists. Herbivores are often specialists, but those that eat a variety of plants may be considered generalists. A well-known example of a specialist animal is the monophagous koala, which subsists almost entirely on eucalyptus leaves. The raccoon is a generalist, because it h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tremarctinae
The Tremarctinae or short-faced bears is a subfamily of Ursidae that contains one living representative, the spectacled bear (''Tremarctos ornatus'') of South America, and several extinct species from four genera: the Florida spectacled bear (''Tremarctos floridanus''), the North American giant short-faced bears ''Arctodus'' (''A. pristinus'' and ''A. simus''), the South American giant short-faced bear ''Arctotherium'' (including ''A. angustidens'', ''A. vetustum'', ''A. bonariense'', ''A. wingei'', and ''A. tarijense)'' as well as ''Plionarctos'' ''(P. edensis and P. harroldorum),'' which is thought to be ancestral to the other three genera. Of these, the giant short-faced bears (''Arctodus simus'' and '' Arctotherium angustidens'') may have been the largest ever carnivorans in the Americas. The group is thought to have originated in eastern North America, and then invaded South America as part of the Great American Interchange. Most short-faced bears became extinct at the end ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctodus
''Arctodus'' is an extinct genus of short-faced bear that inhabited North America during the Pleistocene (~2.5 Mya until 12,000 years ago). There are two recognized species: the lesser short-faced bear (''Arctodus pristinus'') and the giant short-faced bear (''Arctodus simus''). Both species are relatively rare in the fossil record- ''A. pristinus'' was largely restricted to the Early Pleistocene of the eastern United States, whereas ''A. simus'' had a cosmopolitan range, with most finds being from the Late Pleistocene of the US, Mexico and Canada. ''A. simus'' evolved from ''A. pristinus'', but both species likely overlapped in the Middle Pleistocene. Of these species, ''A. simus'' was larger, is known from more complete remains, and is considered one of the most charismatic of North America's megafauna. Today considered to be an enormous omnivore, ''Arctodus simus'' is believed to be one of the largest known terrestrial mammalian carnivorans that has ever existed. However, ''Arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grizzly Bear
The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America. In addition to the mainland grizzly (''Ursus arctos horribilis''), other morphological forms of brown bear in North America are sometimes identified as grizzly bears. These include three living populations—the Kodiak bear (''U. a. middendorffi''), the Kamchatka bear (''U. a. beringianus''), and the peninsular grizzly (''U. a. gyas'')—as well as the extinct California grizzly (''U. a. californicus''†), Mexican grizzly (formerly ''U. a. nelsoni''†), and Ungava-Labrador grizzly (formerly ''U. a. ungavaesis''†). On average, grizzly bears near the coast tend to be larger while inland grizzlies tend to be smaller. The Ussuri brown bear (''U. a. lasiotus''), inhabiting Russia, Northern China, Japan, and Korea, is sometimes referred to as the "black grizzly", although it is no more clos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Port Kennedy, Pennsylvania
Port Kennedy was an industrial village located where U.S. Route 422 (Pottstown Expressway) now crosses the Schuylkill River in Upper Merion Township, Montgomery County, Pennsylvania, United States. Built along the Schuylkill Canal and, after 1838, the Reading Railroad, the village was a center for the lime industry in the 19th century. It was named for Alexander Kennedy, the owner of the quarries and kilns. Beginning in 1871, a number of important fossils were unearthed at Port Kennedy. The location of the find was forgotten until 2006, when the Port Kennedy Bone Cave was rediscovered. Planning for U.S. Route 422 between the Schuylkill Expressway ( Interstate 76) and Trooper Road began in 1964. Most of the village was demolished for construction of the superhighway and Betzwood Bridge, which opened to traffic in 1967. In 1978, the National Park Service seized the land west of the superhighway through eminent domain to expand Valley Forge National Historical Park. Today, U.S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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