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Boreal Kingdom
The Boreal Kingdom or Holarctic Kingdom (Holarctis) is a floristic kingdom identified by botanist Ronald Good (and later by Armen Takhtajan), which includes the temperate to Arctic portions of North America and Eurasia. Its flora is inherited from the ancient supercontinent of Laurasia. However, parts of the floristic kingdom (and most of its Circumboreal Region) were glaciated during the Pleistocene and as a consequence have a very young flora. Cenozoic relicts found refuge in the southern and mountainous parts of the kingdom, especially in the Eastern Asiatic Region and southern North American Atlantic Region. Good noted that many plant species of temperate North America and Eurasia were very closely related, despite their separation by the Atlantic Ocean and the Bering Strait. Millions of years ago, before the opening of the Atlantic Ocean, North America and Eurasia were joined as a single continent, Laurasia. After the opening of the Atlantic, the continents were co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Atlantic Region
North American Atlantic Region is a floristic region within the Holarctic Kingdom identified by Armen Takhtajan and Robert F. Thorne, spanning from the Atlantic and Gulf coasts to the Great Plains and comprising a major part of the United States and southeastern portions of Canada. It is bordered by the Circumboreal floristic region in the north, by the Rocky Mountain and Madrean floristic regions in the west and by the Caribbean floristic region of the Neotropical Kingdom in the south of Florida. The flora of the region comprises two endemic monotypic families, Hydrastidaceae and Leitneriaceae, and is characterized by about a hundred of endemic genera (such as ''Sanguinaria'', ''Leavenworthia'', '' Gillenia'', ''Neviusia'', '' Dionaea'', ''Yeatesia'', ''Pleea''). The degree of species endemism is very high, many species are Tertiary relicts, which survived the Wisconsin glaciation and are now concentrated in the Appalachians (esp. Blue Ridge Mountains) and the Ozarks. A number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaucidiaceae
Ranunculaceae (buttercup or crowfoot family; Latin "little frog", from "frog") is a family of over 2,000 known species of flowering plants in 43 genera, distributed worldwide. The largest genera are ''Ranunculus'' (600 species), ''Delphinium'' (365), '' Thalictrum'' (330), ''Clematis'' (325), and ''Aconitum'' (300). Description Ranunculaceae are mostly herbaceous annuals or perennials, but some are woody climbers (such as ''Clematis'') or shrubs (e.g. '' Xanthorhiza''). Most members of the family have bisexual flowers which can be showy or inconspicuous. Flowers are solitary, but are also found aggregated in cymes, panicles, or spikes. The flowers are usually radially symmetrical but are also found to be bilaterally symmetrical in the genera ''Aconitum'' and ''Delphinium''. The sepals, petals, stamens and carpels are all generally free (not fused), the outer flower segments typically number four or five. The outer stamens may be modified to produce only nectar, as in Aq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalotaxaceae
Cephalotaxaceae is a small grouping of conifers, that included one to three genera closely allied to Taxaceae. However, members of Cephalotaxaceae are now included in Taxaceae by botanists, instead of as a distinct family, based on phylogenetic evidence and close morphological similarities between them. Included species were restricted to east Asia, except for two species of '' Torreya'' found in the southwest and southeast of the United States; fossil evidence shows a much wider prehistorical Northern Hemisphere distribution. The most notable differences between Taxaceae and Cephalotaxaceae concerned the cone aril, which fully encloses the seeds of Cephalotaxaceae, the longer maturation of Cephalotaxaceae seeds and the larger size of the mature seeds. When considered as a distinct family, members of Cephalotaxaceae are much branched, small trees and shrubs. The leaves are evergreen, spirally arranged, often twisted at the base to appear biranked. They are linear to lanceolate, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ginkgoaceae
The Ginkgoaceae is a family of gymnosperms which appeared during the Mesozoic Era, of which the only extant representative is ''Ginkgo biloba'', which is for this reason sometimes regarded as a living fossil A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living foss .... Formerly, however, there were several other genera, and forests of ginkgo existed. Because leaves can take such diverse forms within a single species, these are a poor measure of diversity, although differing structures of wood point to the existence of diverse ginkgo forests in ancient times. References External links * * * * . Plant families Jurassic plants Extant Jurassic first appearances {{Tree-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holarctic
The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical region (which covers most of North America), and Alfred Wallace's Palearctic zoogeographical region (which covers North Africa, and all of Eurasia except for Southeast Asia, the Indian subcontinent, the southern Arabian Peninsula). These regions are further subdivided into a variety of ecoregions. Many ecosystems and the animal and plant communities that depend on them extend across a number of continents and cover large portions of the Holarctic realm. This continuity is the result of those regions’ shared glacial history. Major ecosystems Within the Holarctic realm, there are a variety of ecosystems. The type of ecosystem found in a given area depends on its latitude and the local geography. In the far north, a band of Arctic t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palearctic
The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Siberian region; the Mediterranean Basin; the Sahara and Arabian Deserts; and Western, Central and East Asia. The Palaearctic realm also has numerous rivers and lakes, forming several freshwater ecoregions. The term 'Palearctic' was first used in the 19th century, and is still in use as the basis for zoogeographic classification. History In an 1858 paper for the ''Proceedings of the Linnean Society'', British zoologist Philip Sclater first identified six terrestrial zoogeographic realms of the world: Palaearctic, Aethiopian/ Afrotropic, Indian/ Indomalayan, Australasian, Nearctic, and Neotropical. The six indicated general groupings of fauna, based on shared biogeography and large-scale geographic barriers to migration. Alfred W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nearctic
The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America that are not in the Nearctic realm are Eastern Mexico, Southern Florida, coastal Central Florida, Central America, and the Caribbean islands, which, together with South America, are part of the Neotropical realm. Major ecological regions The World Wildlife Fund (WWF) divides the Nearctic into four bioregions, defined as "geographic clusters of ecoregions that may span several habitat types, but have strong biogeographic affinities, particularly at taxonomic levels higher than the species level (genus, family)." Canadian Shield The Canadian Shield bioregion extends across the northern portion of the continent, from the Aleutian Islands to Newfoundland. It includes the Nearctic's Arctic Tundra and Boreal forest ecoregions. In terms of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogeography
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area.Brown University, "Biogeography." Accessed February 24, 2014. . Phytogeography is the branch of biogeography that studies the distribution of plants. Zoogeography is the branch that studies distribution of animals. Mycogeography is the branch that studies distribution of fungi, such as mushrooms. Knowledge of spatial variation in the numbers and types of organisms is as vital to us today as it was to our early human ancestors, as we adapt to heterogeneous but geographically predictable environments. Biogeography is an integrative field of inquiry that unites concepts and information from ecology, evolutionary biology, taxonomy, geology, physical geography, palaeontology, and climatology.Dansereau, Pierre. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogeographic Realm
A biogeographic realm or ecozone is the broadest biogeographic division of Earth's land surface, based on distributional patterns of terrestrial organisms. They are subdivided into bioregions, which are further subdivided into ecoregions. Description The realms delineate large areas of Earth's surface within which organisms have evolved in relative isolation over long periods of time, separated geographic features, such as oceans, broad deserts, or high mountain ranges, that constitute natural barriers to migration. As such, biogeographic realm designations are used to indicate general groupings of organisms based on their shared biogeography. Biogeographic realms correspond to the floristic kingdoms of botany or zoogeographic regions of zoology. From 1872, Alfred Russel Wallace developed a system of zoogeographic regions, extending the ornithologist Philip Sclater's system of six regions. Biogeographic realms are characterized by the evolutionary history of the org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate
Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind, and precipitation. In a broader sense, climate is the state of the components of the climate system, including the atmosphere, hydrosphere, cryosphere, lithosphere and biosphere and the interactions between them. The climate of a location is affected by its latitude/longitude, terrain, altitude, land use and nearby water bodies and their currents. Climates can be classified according to the average and typical variables, most commonly temperature and precipitation. The most widely used classification scheme was the Köppen climate classification. The Thornthwaite system, in use since 1948, incorporates evapotranspiration along wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of Russia since the latter half of the 16th century, after the Russians Russian conquest of Siberia, conquered lands east of the Ural Mountains. Siberia is vast and sparsely populated, covering an area of over , but home to merely one-fifth of Russia's population. Novosibirsk, Krasnoyarsk and Omsk are the largest cities in the region. Because Siberia is a geographic and historic region and not a political entity, there is no single precise definition of its territorial borders. Traditionally, Siberia extends eastwards from the Ural Mountains to the Pacific Ocean, and includes most of the drainage basin of the Arctic Ocean. The river Yenisey divides Siberia into two parts, Western Siberia, Western and Eastern Siberia, Eastern. Siberia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
