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Effective Evolutionary Time
The hypothesis of effective evolutionary timeK. Rohde: Latitudinal gradients in species diversity: the search for the primary cause, Oikos, 65, 514-527,1992. attempts to explain gradients, in particular latitudinal gradients, in species diversity. It was originally named "time hypothesis".K. Rohde: Latitudinal gradients in species diversity and their causes. I. A review of the hypotheses explaining the gradients. Biologisches Zentralblatt 97, 393-403, 1978a.K. Rohde: Latitudinal gradients in species diversity and their causes. II. Marine parasitological evidence for a time hypothesis. Biologisches Zentralblatt 97, 405-418, 1978b. Background Low (warm) latitudes contain significantly more species than high (cold) latitudes. This has been shown for many animal and plant groups, although exceptions exist (see latitudinal gradients in species diversity). An example of an exception is helminths of marine mammals, which have the greatest diversity in northern temperate seas, possibly bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothesis
A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories. Even though the words "hypothesis" and "theory" are often used interchangeably, a scientific hypothesis is not the same as a scientific theory. A working hypothesis is a provisionally accepted hypothesis proposed for further research in a process beginning with an educated guess or thought. A different meaning of the term ''hypothesis'' is used in formal logic, to denote the antecedent of a proposition; thus in the proposition "If ''P'', then ''Q''", ''P'' denotes the hypothesis (or antecedent); ''Q'' can be called a consequent. ''P'' is the assumption in a (possibly counterfactual) ''What If'' question. The adjective ''hypothetical'', meaning "hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nikolay Timofeev-Ressovsky
Nikolaj Vladimirovich Timofeev-Resovskij (also Timofeyeff-Ressovsky; russian: Николай Владимирович Тимофеев-Ресовский; – 28 March 1981) was a Soviet biologist. He conducted research in radiation genetics, experimental population genetics, and microevolution. His work was of special importance to Soviet biology because it stood in direct opposition to the damage done by Lysenkoism, while his life was highlighted by scientific achievements in the face of severe personal hardship. His life was described by Daniil Granin in the novel ''Zubr''. He was Director of the Genetics Division as the Kaiser Wilhelm Institute for Brain Research in the 1930s, where he received direct funding for his research from the Third Reich, who praised him as one of the world's best geneticists and trusted him because he was an opponent of Communism. Timofeev-Ressovsky was a descendant of the old Russian school of scientists, characterised by broad naturalistic vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Ecology
Evolutionary ecology lies at the intersection of ecology and evolutionary biology. It approaches the study of ecology in a way that explicitly considers the evolutionary histories of species and the interactions between them. Conversely, it can be seen as an approach to the study of evolution that incorporates an understanding of the interactions between the species under consideration. The main subfields of evolutionary ecology are life history evolution, sociobiology (the evolution of social behavior), the evolution of interspecific interactions (e.g. cooperation, predator–prey interactions, parasitism, mutualism) and the evolution of biodiversity and of ecological communities. Evolutionary ecology mostly considers two things: how interactions (both among species and between species and their physical environment) shape species through selection and adaptation, and the consequences of the resulting evolutionary change. Evolutionary models A large part of evolutionary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Drift
Genetic drift, also known as allelic drift or the Wright effect, is the change in the frequency of an existing gene variant (allele) in a population due to random chance. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation. It can also cause initially rare alleles to become much more frequent and even fixed. When few copies of an allele exist, the effect of genetic drift is more notable, and when many copies exist, the effect is less notable. In the middle of the 20th century, vigorous debates occurred over the relative importance of natural selection versus neutral processes, including genetic drift. Ronald Fisher, who explained natural selection using Mendelian genetics, held the view that genetic drift plays at most a minor role in evolution, and this remained the dominant view for several decades. In 1968, population geneticist Motoo Kimura rekindled the debate with his neutral theory of molecular evolution, which claims that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oecologia
''Oecologia'' is an international peer-reviewed English-language journal published by Springer since 1968 (some articles were published in German or French until 1976). The journal publishes original research in a range of topics related to plant and animal ecology. Oecologia has an international focus and presents original papers, methods, reviews and special topics. Papers focus on population ecology, plant-animal interactions, ecosystem ecology, community ecology, global change ecology, conservation ecology, behavioral ecology and physiological ecology. Oecologia had an impact factor of 3.298 (2021) and is ranked 37 out of 136 in the subject category "ecology". Editorial Board As of December 2022, the journal has six editors in chief: * Carlos L. Ballaré (plant-microbe/plant-animal interactions), University of Buenos Aires, Argentina * Nina Farwig (terrestrial invertebrate ecology), University of Marburg, Germany * Indrikis Krams (terrestrial vertebrate ecology), Universi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthos
Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.Benthos from the Census of Antarctic Marine Life website This community lives in or near marine or freshwater sedimentary environments, from s along the , out to the , and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapoport's Rule
Rapoport's rule is an ecogeographical rule that states that latitudinal ranges of plants and animals are generally smaller at lower latitudes than at higher latitudes. Background Stevens (1989) named the rule after Eduardo H. Rapoport, who had earlier provided evidence for the phenomenon for subspecies of mammals (Rapoport 1975, 1982). Stevens used the rule to "explain" greater species diversity in the tropics in the sense that latitudinal gradients in species diversity and the rule have identical exceptional data and so must have the same underlying cause. Narrower ranges in the tropics would facilitate more species to coexist. He later extended the rule to altitudinal gradients, claiming that altitudinal ranges are greatest at greater altitudes (Stevens 1992), and to depth gradients in the oceans (Stevens 1996Stevens, G. C. (1996). Extending Rapoport's rule to Pacific marine fishes. Journal of Biogeography 23:149–154.). The rule has been the focus of intense discussion and give ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timofeeff-Ressovsky
Nikolaj Vladimirovich Timofeev-Resovskij (also Timofeyeff-Ressovsky; russian: Николай Владимирович Тимофеев-Ресовский; – 28 March 1981) was a Soviet biologist. He conducted research in radiation genetics, experimental population genetics, and microevolution. His work was of special importance to Soviet biology because it stood in direct opposition to the damage done by Lysenkoism, while his life was highlighted by scientific achievements in the face of severe personal hardship. His life was described by Daniil Granin in the novel ''Zubr''. He was Director of the Genetics Division as the Kaiser Wilhelm Institute for Brain Research in the 1930s, where he received direct funding for his research from the Third Reich, who praised him as one of the world's best geneticists and trusted him because he was an opponent of Communism. Timofeev-Ressovsky was a descendant of the old Russian school of scientists, characterised by broad naturalisti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homoiothermic
Homeothermy, homothermy or homoiothermy is thermoregulation that maintains a stable internal body temperature regardless of external influence. This internal body temperature is often, though not necessarily, higher than the immediate environment (from Greek ὅμοιος ''homoios'' "similar" and θέρμη ''thermē'' "heat"). Homeothermy is one of the three types of thermoregulation in warm-blooded animal species. Homeothermy's opposite is poikilothermy. A poikilotherm is an organism that does not maintain a fixed internal temperature but rather fluctuates based on their environment and physical behaviour. Homeotherms are ''not'' necessarily endothermic. Some homeotherms may maintain constant body temperatures through behavioral mechanisms alone, ''i.e.'', behavioral thermoregulation. Many reptiles use this strategy. For example, desert lizards are remarkable in that they maintain near-constant activity temperatures that are often within a degree or two of their lethal crit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latitudinal Gradients In Species Diversity
Species richness, or biodiversity, increases from the poles to the tropics for a wide variety of terrestrial and marine organisms, often referred to as the latitudinal diversity gradient. The latitudinal diversity gradient is one of the most widely recognized patterns in ecology. It has been observed to varying degrees in Earth's past. A parallel trend has been found with elevation (elevational diversity gradient), though this is less well-studied. Explaining the latitudinal diversity gradient has been called one of the great contemporary challenges of biogeography and macroecology (Willig et al. 2003, Pimm and Brown 2004, Cardillo et al. 2005). The question "What determines patterns of species diversity?" was among the 25 key research themes for the future identified in 125th Anniversary issue of ''Science'' (July 2005). There is a lack of consensus among ecologists about the mechanisms underlying the pattern, and many hypotheses have been proposed and debated. A recent review n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poikilotherm
A poikilotherm () is an animal whose internal temperature varies considerably. Poikilotherms have to survive and adapt to environmental stress. One of the most important stressors is temperature change, which can lead to alterations in membrane lipid order and can cause protein unfolding and denaturation at elevated temperatures. It is the opposite of a homeotherm, an animal which maintains thermal homeostasis. While the term in principle can apply to all organisms, it is generally only applied to animals, and mostly to vertebrates. Usually the fluctuations are consequence of variation in the ambient environmental temperature. Many terrestrial ectotherms are poikilothermic. However some ectotherms remain in temperature-constant environments to the point that they are actually able to maintain a constant internal temperature (i.e. are homeothermic). It is this distinction that often makes the term "poikilotherm" more useful than the vernacular "cold-blooded", which is sometimes us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernhard Rensch
Bernhard Rensch (21 January 1900 – 4 April 1990) was a German evolutionary biologist and ornithologist who did field work in Indonesia and India. Starting his scientific career with pro-Lamarckian views, he shifted to selectionism and became one of the architects of the modern synthesis in evolutionary biology, which he popularised in Germany. Besides his work on how environmental factors influenced the evolution of geographically isolated populations and on evolution above the species level, which contributed to the modern synthesis, he also worked extensively in the area of animal behavior (ethology) and on philosophical aspects of biological science. His education and scientific work were interrupted by service in the German military during both World War I and World War II. Biography Rensch was born in Thale and as a young boy, he took an interest in observing the natural world and discovered a talent for drawing and painting. He served in the German army from 1917–1920 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
