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Organisms At High Altitude
Organisms can live at high altitude, either on land, in water, or while flying. Decreased oxygen availability and decreased temperature make life at such altitudes challenging, though many species have been successfully evolutionary adaptation, adapted via considerable physiology, physiological changes. As opposed to short-term Effects of high altitude on humans, acclimatisation (immediate physiological response to changing environment), high-altitude adaptation means irreversible, adaptive evolution, evolved physiological responses to high-altitude environments, associated with heritable ethology, behavioural and mutation, genetic changes. Among vertebrates, only few mammals (such as Phyllotis, leaf-eared mice, yaks, ibexes, Tibetan gazelles, vicunas, llamas, mountain goats, etc.) and certain birds are known to have completely adapted to high-altitude environments. Human populations such as some tibetan people, Tibetans, South Americans and people of Ethiopia, Ethiopians live in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Americans
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion of the Americas. South America is bordered on the west by the Pacific Ocean, on the north and east by the Atlantic Ocean, and to the south by the Drake Passage; North America and the Caribbean Sea lie to the northwest. The continent includes twelve sovereign states: Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, and Venezuela; two dependent territory, dependent territories: the Falkland Islands and South Georgia and the South Sandwich Islands; and one administrative division, internal territory: French Guiana. The Dutch Caribbean ABC islands (Leeward Antilles), ABC islands (Aruba, Bonaire, and Curaçao) and Trinidad and Tobago are geologically located on the South-American continental shel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euophrys Omnisuperstes
''Euophrys omnisuperstes'', the Himalayan jumping spider, is a small jumping spider that lives at elevations of up to in the Himalayas, including Mount Everest, making it a candidate for the highest known permanent resident on Earth. They are found among rocky debris, feeding on tiny stray springtails and flies. The specific epithet means ''standing above everything'', and is from Latin ''omni'' ("all") + ''superstes'' ("stand over, stand upon, survive"). Discovery In 1924, Richard Hingston was the naturalist on the British expedition to Mount Everest. In 1925, he reported that spiders had been observed living permanently in rocky areas surrounded by snow and ice at , about above the highest plant growth. His observation that "for food they eat one another" was later described as a "self-defeating notion" and helped to support the view that the spiders had been blown there and were not permanent residents. In 1954, Lawrence W. Swan joined an American expedition to Makalu in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NBC News
NBC News is the news division of the American broadcast television network NBC. The division operates under NBCUniversal Media Group, a division of NBCUniversal, which is itself a subsidiary of Comcast. The news division's various operations report to the president of NBC News, Rebecca Blumenstein. The NBCUniversal News Group also comprises MSNBC, the network's 24-hour liberal cable news channel, as well as business and consumer news channels CNBC and CNBC World, the Spanish language and United Kingdom-based Sky News. NBC News aired the first regularly scheduled news program in American broadcast television history on February 21, 1940. The group's broadcasts are produced and aired from 30 Rockefeller Plaza, NBCUl's headquarters in New York City. The division presides over the flagship evening newscast ''NBC Nightly News'', the world's first of its genre morning television program, ''Today (American TV program), Today'', and the longest-running television series in American hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space
Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as '' spacetime''. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. In the 19th and 20th centuries mathematicians began to examine geometries that are non-Euclidean, in which space is conceived as '' curved'', rather than '' flat'', as in the Euclidean space. According to Albert Einstein's theory of general relativity, space around gravitational fields deviates from Euclidean space. Experimental tests of general relativity have confirmed that non-Euclidean geometries provide a bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annual Review Of Physiology
The ''Annual Review of Physiology'' is a peer-reviewed academic journal that publishes review articles about physiology. First published in 1939 through a collaboration between the American Physiological Society and Annual Reviews (publisher), Annual Reviews, it was published solely by Annual Reviews after 1962. It covers various aspects of physiology, including cardiac, renal, respiratory, and gastrointestinal physiology, among other subfields. As of 2023, ''Annual Review of Physiology'' is being published as open access, under the Subscribe to Open model. As of 2024, ''Journal Citation Reports'' lists the journal's 2023 impact factor as 15.7, ranking it second of 85 journal titles in the category "Physiology". History In 1938, the Annual Review of Biochemistry, Ltd and the American Physiological Society agreed to collaborate to create a new journal. As a result, the Annual Review of Biochemistry, Ltd, previously just the publisher of the Annual Review of Biochemistry, journal of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absolute Zero
Absolute zero is the lowest possible temperature, a state at which a system's internal energy, and in ideal cases entropy, reach their minimum values. The absolute zero is defined as 0 K on the Kelvin scale, equivalent to −273.15 °C on the Celsius, Celsius scale, and −459.67 °F on the Fahrenheit scale. The Kelvin and Rankine temperature scales set their zero points at absolute zero by design. This limit can be estimated by extrapolating the ideal gas law to the temperature at which the volume or pressure of a classical gas becomes zero. At absolute zero, there is no thermal motion. However, due to quantum mechanics, quantum effects, the particles still exhibit minimal motion mandated by the Uncertainty principle, Heisenberg uncertainty principle and, for a system of fermions, the Pauli exclusion principle. Even if absolute zero could be achieved, this residual quantum motion would persist. Although absolute zero can be approached, it cannot be reached. Som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tardigrades
Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged Segmentation (biology), segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them . In 1776, the Italian biologist Lazzaro Spallanzani named them Tardigrada, which means 'slow walkers'. They live in diverse regions of Earth's biospheremountaintops, the deep sea, tropical rainforests, and the Antarctic. Tardigrades are among the most resilient animals known, with individual species able to survive extreme conditions – such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation – that would quickly kill most other forms of life. Tardigrades have survived exposure to outer space. There are about 1,500 known species in the phylum Tardigrada, a part of the superphylum Ecdysozoa. The earliest known fossil is from the Cambrian, some 500 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EPAS1
Endothelial PAS domain-containing protein 1 (EPAS1, also known as hypoxia-inducible factor-2alpha (HIF-2α)) is a protein that is encoded by the ''EPAS1'' gene in mammals. It is a type of hypoxia-inducible factor, a group of transcription factors involved in the physiological response to oxygen concentration. The gene is active under hypoxic conditions. It is also important in the development of the heart, and for maintaining the catecholamine balance required for protection of the heart. Mutation often leads to neuroendocrine tumors. However, several characterized alleles of ''EPAS1'' contribute to high-altitude adaptation in humans. One such allele, which has been inherited from Denisovan archaic hominins, is known to confer increased athletic performance in some people, and has therefore been referred to as the "super athlete gene". Function The EPAS1 gene encodes one subunit of a transcription factor involved in the induction of genes regulated by oxygen, and which is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is Cladogram#Homoplasies, homoplasy. The recurrent evolution of flight is a classic example, as flying pterygota, insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas ''homology (biology), homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different trai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with selective breeding, artificial selection, which is intentional, whereas natural selection is not. Genetic diversity, Variation of traits, both Genotype, genotypic and phenotypic, exists within all populations of organisms. However, some traits are more likely to facilitate survival and reproductive success. Thus, these traits are passed the next generation. These traits can also become more Allele frequency, common within a population if the environment that favours these traits remains fixed. If new traits become more favoured due to changes in a specific Ecological niche, niche, microevolution occurs. If new traits become more favoured due to changes in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethiopian Highlands
The Ethiopian Highlands (also called the Abyssinian Highlands) is a rugged mass of mountains in Ethiopia in Northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below , while the summits reach heights of up to . It is sometimes called the "Roof of Africa" due to its height and large area. It is the only country in the region with such a high elevated surface. This elevated surface is bisected diagonally by the Great East African Rift System which extends from Syria to Mozambique across the East African Lakes. Most of the Ethiopian Highlands are part of central and northern Ethiopia, and its northernmost portion reaches into Eritrean Highlands, Eritrea. History In the southern parts of the Ethiopian Highlands once was located the Kingdom of Kaffa, a medieval and Early modern period, early modern state, whence the coffee plant was exported to the Arabian Peninsula. The land of the former kingdom is mountainou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
