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Alexander Kovalevsky
Alexander Onufrievich Kovalevsky (russian: Алекса́ндр Ону́фриевич Ковале́вский, 7 November 1840 in Vorkovo, Dvinsky Uyezd, Vitebsk Governorate, Russian Empire – 1901, St. Petersburg, Russian Empire) was a Russian Imperial embryologist, who studied medicine at the University of Heidelberg and became professor at the University of St Petersburg. He was the brother of the paleontologist Vladimir Kovalevsky, and the brother-in-law of the mathematician Sofya Kovalevskaya. Discoveries Kowalevsky's family belonged to Russian nobility. He showed that all animals go through a period of gastrulation. Kovalevsky discovered that tunicates are not molluscs, but that their larval stage has a notochord and pharyngeal slits, like vertebrates. Further, these structures develop from the same germ layers in the embryo as the equivalent structures in vertebrates, so he argued that the tunicates should be grouped with the vertebrates as chordates. 19th-cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The gastropods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
People From Dvinsky Uyezd
A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility. The defining features of personhood and, consequently, what makes a person count as a person, differ widely among cultures and contexts. In addition to the question of personhood, of what makes a being count as a person to begin with, there are further questions about personal identity and self: both about what makes any particular person that particular person instead of another, and about what makes a person at one time the same person as they were or will be at another time despite any intervening changes. The plural form "people" is often used to refer to an entire nation or ethnic group (as in "a people"), and this was the original meaning of the word; it subsequently acquired its use as a plural form of per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
People From Preiļi Municipality
A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility. The defining features of personhood and, consequently, what makes a person count as a person, differ widely among cultures and contexts. In addition to the question of personhood, of what makes a being count as a person to begin with, there are further questions about personal identity and self: both about what makes any particular person that particular person instead of another, and about what makes a person at one time the same person as they were or will be at another time despite any intervening changes. The plural form "people" is often used to refer to an entire nation or ethnic group (as in "a people"), and this was the original meaning of the word; it subsequently acquired its use as a plural form of per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1901 Deaths
Nineteen or 19 may refer to: * 19 (number), the natural number following 18 and preceding 20 * one of the years 19 BC, AD 19, 1919, 2019 Films * ''19'' (film), a 2001 Japanese film * ''Nineteen'' (film), a 1987 science fiction film Music * 19 (band), a Japanese pop music duo Albums * ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * ''Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * ''XIX'' (EP), a 2019 EP by 1the9 Songs * "19" (song), a 1985 song by British musician Paul Hardcastle. * "Nineteen", a song by Bad4Good from the 1992 album ''Refugee'' * "Nineteen", a song by Karma to Burn from the 2001 album ''Almost Heathen''. * "Nineteen" (song), a 2007 song by American singer Billy Ray Cyrus. * "Nineteen", a song by Tegan and Sara from the 2007 album '' The Con''. * "XIX" (song), a 2014 song by Slipkno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1840 Births
__NOTOC__ Year 184 ( CLXXXIV) was a leap year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Eggius and Aelianus (or, less frequently, year 937 ''Ab urbe condita''). The denomination 184 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place China * The Yellow Turban Rebellion and Liang Province Rebellion break out in China. * The Disasters of the Partisan Prohibitions ends. * Zhang Jue leads the peasant revolt against Emperor Ling of Han of the Eastern Han Dynasty. Heading for the capital of Luoyang, his massive and undisciplined army (360,000 men), burns and destroys government offices and outposts. * June – Ling of Han places his brother-in-law, He Jin, in command of the imperial army and sends them to attack the Yellow Turban rebels. * Winter – Zha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linnean Society Of London
The Linnean Society of London is a learned society dedicated to the study and dissemination of information concerning natural history, evolution, and taxonomy. It possesses several important biological specimen, manuscript and literature collections, and publishes academic journals and books on plant and animal biology. The society also awards a number of prestigious medals and prizes. A product of the 18th-century enlightenment, the Society is the oldest extant biological society in the world and is historically important as the venue for the first public presentation of the theory of evolution by natural selection on 1 July 1858. The patron of the society was Queen Elizabeth II. Honorary members include: King Charles III of Great Britain, Emeritus Emperor Akihito of Japan, King Carl XVI Gustaf of Sweden (both of latter have active interests in natural history), and the eminent naturalist and broadcaster Sir David Attenborough. History Founding The Linnean Society ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marion Kowaleswsky
Marion may refer to: People *Marion (given name) *Marion (surname) *Marion Silva Fernandes, Brazilian footballer known simply as "Marion" *Marion (singer), Filipino singer-songwriter and pianist Marion Aunor (born 1992) Places Antarctica * Marion Nunataks, Charcot Island Australia * City of Marion, a local government area in South Australia * Marion, South Australia, a suburb of Adelaide Cyprus * Marion, Cyprus, an ancient city-state South Africa *Marion Island, one of the Prince Edward Islands United States * Marion, Alabama * Marion, Arkansas * Marion, Connecticut ** Marion Historic District (Cheshire and Southington, Connecticut) * Marion, Georgia * Marion, Illinois * Marion, Indiana, Grant County * Marion, Shelby County, Indiana * Marion, Iowa * Marion, Kansas ** Marion County Lake ** Marion Reservoir * Marion, Kentucky * Marion, Louisiana * Marion, Massachusetts * Marion Station, Maryland, often referred to as just "Marion" * Marion, Michigan * Marion, Minnesota * Marion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Developmental Biology
Evolutionary developmental biology (informally, evo-devo) is a field of biological research that compares the developmental processes of different organisms to infer how developmental processes evolved. The field grew from 19th-century beginnings, where embryology faced a mystery: zoologists did not know how embryonic development was controlled at the molecular level. Charles Darwin noted that having similar embryos implied common ancestry, but little progress was made until the 1970s. Then, recombinant DNA technology at last brought embryology together with molecular genetics. A key early discovery was of homeotic genes that regulate development in a wide range of eukaryotes. The field is composed of multiple core evolutionary concepts. One is deep homology, the finding that dissimilar organs such as the eyes of insects, vertebrates and cephalopod molluscs, long thought to have evolved separately, are controlled by similar genes such as ''pax-6'', from the evo-devo gene toolk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry. In a ''rooted'' phylogenetic tree, each node with descendants represents the inferred most recent common ancestor of those descendants, and the edge lengths in some trees may be interpreted as time estimates. Each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed. Trees are useful in fields of biology such as bioinformatics, systematics, and phylogenetics. ''Unrooted'' trees illustrate only the relatedness of the leaf nodes and do not require the ancestral root to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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