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Nunatak Hypothesis
In biogeography, particularly phytogeography, the nunatak hypothesis about the origin of a biota in formerly glaciated areas is the idea that some or many species have survived the inhospitable period on icefree land such as nunataks. Its antithesis is the '' tabula rasa hypothesis'', which posits that all species have immigrated into completely denuded land after the retreat of glaciers. By the mid-20th Century, the nunatak hypothesis was widely accepted among biologists working on the floras of Greenland and Scandinavia. However, while modern geology has established the presence of ice-free areas during the last glacial maximum in both Greenland and Scandinavia, molecular techniques have revealed limited between-region genetic differentiation in many Arctic taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogeography
Biogeography is the study of the species distribution, distribution of species and ecosystems in geography, geographic space and through evolutionary history of life, geological time. Organisms and biological community (ecology), communities often vary in a regular fashion along geographic gradients of latitude, elevation, allopatric speciation, isolation and habitat species-area curve, area. 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 Natural environment, environments. Biogeography is an integrative field of inquiry that unites concepts and information from ecology, evolutionary biology, taxonomy (bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytogeography
Phytogeography (from Greek φυτόν, ''phytón'' = "plant" and γεωγραφία, ''geographía'' = "geography" meaning also distribution) or botanical geography is the branch of biogeography that is concerned with the geographic distribution of plant species and their influence on the earth's surface. Phytogeography is concerned with all aspects of plant distribution, from the controls on the distribution of individual species ranges (at both large and small scales, see species distribution) to the factors that govern the composition of entire communities and floras. Geobotany, by contrast, focuses on the geographic space's influence on plants. Fields Phytogeography is part of a more general science known as biogeography. Phytogeographers are concerned with patterns and process in plant distribution. Most of the major questions and kinds of approaches taken to answer such questions are held in common between phyto- and zoogeographers. Phytogeography in wider sense (or geobo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nunatak
A nunatak (from Inuit language, Inuit ) is the summit or ridge of a mountain that protrudes from an ice field or glacier that otherwise covers most of the mountain or ridge. They often form natural pyramidal peaks. Isolated nunataks are also called glacial islands, and smaller nunataks rounded by glacial action may be referred to as rognons. The word is of Greenlandic language, Greenlandic origin and has been used in English since the 1870s. Description The term ''nunatak'' is typically used in areas where a permanent ice sheet is present and the ridge protrudes above the sheet.J. J. Zeeberg, ''Climate and Glacial History of the Novaya Zemlya Archipelago, Russian Arctic''. pp. 82–84 Nunataks present readily identifiable landmark reference points in glaciers or ice caps and are often named. While some are isolated, they can also form dense clusters, such as Queen Louise Land in Greenland. Nunataks are generally angular and jagged, hampering the formation of glacial ice on thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tabula Rasa
''Tabula rasa'' (; Latin for "blank slate") is the idea of individuals being born empty of any built-in mental content, so that all knowledge comes from later perceptions or sensory experiences. Proponents typically form the extreme "nurture" side of the nature versus nurture debate, arguing that humans are born without any "natural" psychological traits and that all aspects of one's personality, social and emotional behaviour, knowledge, or sapience are later imprinted by one's environment onto the mind as one would onto a wax tablet. This idea is the central view posited in the theory of knowledge known as empiricism. Empiricists disagree with the doctrines of innatism or rationalism, which hold that the mind is born already in possession of specific knowledge or rational capacity. Etymology ''Tabula rasa'' is a Latin phrase often translated as ''clean slate'' in English and originates from the Roman '' tabula'', a wax-covered tablet used for notes, which was blanked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenland
Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenland are full Danish nationality law, citizens of Denmark and European Union citizenship, of the European Union. Greenland is one of the Special territories of members of the European Economic Area#Overseas countries and territories, Overseas Countries and Territories of the European Union and is part of the Council of Europe. It is the List of islands by area, world's largest island, and lies between the Arctic Ocean, Arctic and Atlantic oceans, east of the Arctic Archipelago, Canadian Arctic Archipelago. It is the location of the northernmost point of land in the world; Kaffeklubben Island off the northern coast is the world's Northernmost point of land, northernmost undisputed point of land—Cape Morris Jesup on the mainland was thought to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scandinavia
Scandinavia is a subregion#Europe, subregion of northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. ''Scandinavia'' most commonly refers to Denmark, Norway, and Sweden. It can sometimes also refer to the Scandinavian Peninsula (which excludes Denmark but includes a part of northern Finland). In English usage, Scandinavia is sometimes used as a synonym for Nordic countries. Iceland and the Faroe Islands are sometimes included in Scandinavia for their Ethnolinguistics, ethnolinguistic relations with Sweden, Norway and Denmark. While Finland differs from other Nordic countries in this respect, some authors call it Scandinavian due to its economic and cultural similarities. The geography of the region is varied, from the Norwegian fjords in the west and Scandinavian mountains covering parts of Norway and Sweden, to the low and flat areas of Denmark in the south, as well as archipelagos and lakes in the east. Most of the population ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctic
The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway (Nordland, Troms, Finnmark, Svalbard and Jan Mayen), northernmost Sweden (Västerbotten, Norrbotten and Lapland (Sweden), Lappland), northern Finland (North Ostrobothnia, Kainuu and Lapland (Finland), Lappi), Russia (Murmansk Oblast, Murmansk, Siberia, Nenets Autonomous Okrug, Nenets Okrug, Novaya Zemlya), the United States (Alaska), Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenland), and northern Iceland (Grímsey and Kolbeinsey), along with the Arctic Ocean and adjacent seas. Land within the Arctic region has seasonally varying cryosphere, snow and ice cover, with predominantly treeless permafrost under the tundra. Arctic seas contain seasonal sea ice in many places. The Arctic region is a unique area among Earth's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxon
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion, especially in the context of rank-based (" Linnaean") nomenclature (much less so under phylogenetic nomenclature). If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were presumably set forth in prehistoric times by hunter-gatherers, as suggested by the fairly sophisticated folk taxonomies. Much later, Aristotle, and later st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Hypotheses
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, origin, evolution, and distribution of life. Central to biology are five fundamental themes: the cell as the basic unit of life, genes and heredity as the basis of inheritance, evolution as the driver of biological diversity, energy transformation for sustaining life processes, and the maintenance of internal stability (homeostasis). Biology examines life across multiple levels of organization, from molecules and cells to organisms, populations, and ecosystems. Subdisciplines include molecular biology, physiology, ecology, evolutionary biology, developmental biology, and systematics, among others. Each of these fields applies a range of methods to investigate biological phenomena, including scientific method, observation, experimentation, and mathematical modeling. Modern bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytogeography
Phytogeography (from Greek φυτόν, ''phytón'' = "plant" and γεωγραφία, ''geographía'' = "geography" meaning also distribution) or botanical geography is the branch of biogeography that is concerned with the geographic distribution of plant species and their influence on the earth's surface. Phytogeography is concerned with all aspects of plant distribution, from the controls on the distribution of individual species ranges (at both large and small scales, see species distribution) to the factors that govern the composition of entire communities and floras. Geobotany, by contrast, focuses on the geographic space's influence on plants. Fields Phytogeography is part of a more general science known as biogeography. Phytogeographers are concerned with patterns and process in plant distribution. Most of the major questions and kinds of approaches taken to answer such questions are held in common between phyto- and zoogeographers. Phytogeography in wider sense (or geobo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogeography
Biogeography is the study of the species distribution, distribution of species and ecosystems in geography, geographic space and through evolutionary history of life, geological time. Organisms and biological community (ecology), communities often vary in a regular fashion along geographic gradients of latitude, elevation, allopatric speciation, isolation and habitat species-area curve, area. 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 Natural environment, environments. Biogeography is an integrative field of inquiry that unites concepts and information from ecology, evolutionary biology, taxonomy (bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Ages
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 and icehouse Earth#Greenhouse Earth, greenhouse periods during which there are no glaciers on the planet. Earth is currently in the ice age called Quaternary glaciation. Individual pulses of cold climate within an ice age are termed ''glacial periods'' (''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, the term ''ice age'' is defined by the presence of extensive ice sheets in the northern and southern hemispheres. By this definition, the current Holocene epoch is an interglacial period of an ice age. The accumulation of anthropogenic greenhouse gases is projected to delay the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
