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Middle Arctic Tundra
The Middle Arctic tundra ecoregion (WWF ID: NA1115) covers a broad stretch of northern Canada - the southern islands of the Arctic Archipelago, plus the northern mainland of Nunavut and, across Hudson Bay to the east, a portion of northern Quebec. This is the coldest and driest ecoregion in Canada, and can be referred to as a 'polar desert'. It is an important region for breeding and migratory birds, and supports 80% of the world's muskox. Location and description The ecoregion stretches over from west to east: Banks Island, Victoria Island, King William Island, northeast Nunavut, and the southern portions of Prince of Wales Island and Baffin Island. Most of the territory rolling lowlands (mean elevation is ). The ecoregion to the north is the 'High Arctic tundra' (colder and wetter), to the south is the Low Arctic tundra (warmer and wetter). The bedrock under the western extent is Paleozoic and Mesozoic sedimentary rock with a relatively flat cover of glacial moraines and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muskoxen
The muskox (''Ovibos moschatus'', in Latin "musky sheep-ox"), also spelled musk ox and musk-ox, plural muskoxen or musk oxen (in iu, ᐅᒥᖕᒪᒃ, umingmak; in Woods Cree: ), is a hoofed mammal of the family Bovidae. Native to the Arctic, it is noted for its thick coat and for the strong odor emitted by males during the seasonal rut, from which its name derives. This musky odor has the effect of attracting females during mating season. Its Inuktitut name "umingmak" translates to "the bearded one". Its Woods Cree names "mâthi-môs" and "mâthi-mostos" translate to "ugly moose" and "ugly bison", respectively. Muskoxen primarily live in Greenland and the Canadian Arctic of the Northwest Territories and Nunavut, with reintroduced populations in the American state of Alaska, the Canadian territory of Yukon, and Siberia, and an introduced population in Norway, part of which emigrated to Sweden, where a small population now lives. Evolution Extant relatives The muskox is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Banks Island
Banks Island is one of the larger members of the Arctic Archipelago. Situated in the Inuvik Region, and part of the Inuvialuit Settlement Region, of the Northwest Territories, it is separated from Victoria Island to its east by the Prince of Wales Strait and from the mainland by Amundsen Gulf to its south. The Beaufort Sea lies to its west, and to its northeast M'Clure Strait separates the island from Prince Patrick Island and Melville Island. It is home to at least fourteen mammal species including the Peary caribou, barren-ground caribou, and polar bears. At one time over 68,000 muskoxen lived on the island, the majority of the world's population. However, the bacterium ''Erysipelothrix rhusiopathiae'' has led to a sharp decline in their numbers. The island is the summer home to hundreds of thousands of migratory birds who nest at Banks Island Migratory Bird Sanctuary No. 1 and Banks Island Migratory Bird Sanctuary No. 2. As of the 2016 census it had a human population ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saxifraga
''Saxifraga'' is the largest genus in the family Saxifragaceae, containing about 465 species of holarctic perennial plants, known as saxifrages or rockfoils. The Latin word ''saxifraga'' means literally "stone-breaker", from Latin ' ("rock" or "stone") + ' ("to break"). It is usually thought to indicate a medicinal use for treatment of urinary calculi (known as kidney or bladder stones), rather than breaking rocks apart. Description Most saxifrages are small perennial, biennial (e.g. '' S. adscendens'') or annual (e.g. '' S. tridactylites'') herbaceous plants whose basal or cauline leaves grow close to the ground, often in a rosette. The leaves typically have a more or less incised margin; they may be succulent, needle-like and/or hairy, reducing evaporation. The inflorescence or single flower clusters rise above the main plant body on naked stalks. The small actinomorphic hermaphrodite flowers have five petals and sepals and are usually white, but red to yellow in some specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alnus
Alders are trees comprising the genus ''Alnus'' in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species extending into Central America, as well as the northern and southern Andes. Description With a few exceptions, alders are deciduous, and the leaves are alternate, simple, and serrated. The flowers are catkins with elongate male catkins on the same plant as shorter female catkins, often before leaves appear; they are mainly wind-pollinated, but also visited by bees to a small extent. These trees differ from the birches (''Betula'', another genus in the family) in that the female catkins are woody and do not disintegrate at maturity, opening to release the seeds in a similar manner to many conifer cones. The largest species are red alder (''A. rubra'') on the west coast of North America, and black alder (''A. glutinosa''), native to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Betula
A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 to 60 known taxa of which 11 are on the IUCN 2011 Red List of Threatened Species. They are a typically rather short-lived pioneer species widespread in the Northern Hemisphere, particularly in northern areas of temperate climates and in boreal climates. Description Birch species are generally small to medium-sized trees or shrubs, mostly of northern temperate and boreal climates. The simple leaves are alternate, singly or doubly serrate, feather-veined, petiolate and stipulate. They often appear in pairs, but these pairs are really borne on spur-like, two-leaved, lateral branchlets. The fruit is a small samara, although the wings may be obscure in some species. They differ from the alders (''Alnus'', another genus in the family) i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salix Arctica
''Salix arctica'', the Arctic willow, is a tiny creeping willow (family Salicaceae). It is adapted to survive in Arctic conditions, specifically tundras. Description ''S. arctica'' is typically a low shrub growing to only in height, rarely to , although it may reach in height in the Pacific Northwest. It has round, shiny green leaves long and broad; they are pubescent, with long, silky, silvery hairs. Like the rest of the willows, Arctic willow is dioecious, with male and female catkins on separate plants. As a result, the plant's appearance varies; the female catkins are red-coloured, while the male catkins are yellow-coloured.Jepson Flora''Salix arctica''/ref> Despite its small size, it is a long-lived plant, growing extremely slowly in the severe arctic climate; one in eastern Greenland was found to be 236 years old. Hybrids with '' Salix arcticola'' and ''Salix glauca'' are known. Distribution and habitat The Arctic willow grows in tundra and rocky moorland, and is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treeline
The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snowpack, or associated lack of available moisture). The tree line is sometimes distinguished from a lower timberline, which is the line below which trees form a forest with a closed Canopy (biology), canopy. At the tree line, tree growth is often sparse, stunted, and deformed by wind and cold. This is sometimes known as ''krummholz'' (German for "crooked wood"). The tree line often appears well-defined, but it can be a more gradual transition. Trees grow shorter and often at lower densities as they approach the tree line, above which they are unable to grow at all. Given a certain latitude, the tree line is approximately 300 to 1000 meters below the permanent snow line and roughly parallel to it. Causes Due to their vertical structure, tree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Köppen Climate Classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist Rudolf Geiger (1894–1981) introduced some changes to the classification system, which is thus sometimes called the Köppen–Geiger climate classification system. The Köppen climate classification divides climates into five main climate groups, with each group being divided based on seasonal precipitation and temperature patterns. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (temperate), ''D'' (continental), and ''E'' (polar). Each group and subgroup is represented by a letter. All climates are assigned a main group (the first letter). All climates except for those in the ''E'' group are assigned a seasonal precipitation subgroup (the second letter). For example, ''Af'' indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permafrost
Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface is underlain by permafrost, with the total area of around 18 million km2. This includes substantial areas of Alaska, Greenland, Canada and Siberia. It can also be located on mountaintops in the Southern Hemisphere and beneath ice-free areas in the Antarctic. Permafrost does not have to be the first layer that is on the ground. It can be from an inch to several miles deep under the Earth's surface. It frequently occurs in ground ice, but it can also be present in non-porous bedrock. Permafrost is formed from ice holding various types of soil, sand, and rock in combination. Permafrost contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide, making tundra soil a carbon sink. As global war ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precambrian
The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga) to the beginning of the Cambrian Period, about million years ago ( Ma), when hard-shelled creatures first appeared in abundance. Overview Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian reptiles, like the dinosaurs; an abundance of conifers and ferns; a hot Greenhouse and icehouse earth, greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since Cambrian explosion, complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic. The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs, Pterosaur, pterosaurs, Mosasaur, mosasaurs, and Plesiosaur, plesiosaurs. The Mesozoic was a time of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''zōḗ'' (), "life", meaning "ancient life" ). It is the longest of the Phanerozoic eras, lasting from , and is subdivided into six geologic periods (from oldest to youngest): # Cambrian # Ordovician # Silurian # Devonian # Carboniferous # Permian The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon and is followed by the Mesozoic Era. The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Arthropods, molluscs, fish, amphibians, reptiles, and synapsids all evolved during the Paleozoic. Life began in the ocean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
