The Experts below are selected from a list of 540 Experts worldwide ranked by ideXlab platform
M. Justin O'riain - One of the best experts on this subject based on the ideXlab platform.
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Sperm structure and motility in the eusocial naked mole-rat, Heterocephalus glaber: a case of degenerative Orthogenesis in the absence of sperm competition?
BMC evolutionary biology, 2011Co-Authors: Gerhard Van Der Horst, Liana Maree, Sanet H. Kotzé, M. Justin O'riainAbstract:We have studied sperm structure and motility in a eusocial rodent where reproduction is typically restricted to a single male and behaviourally dominant queen. Males rarely compete for access to the queen during her estrus cycle, suggesting little or no role for sperm competition. Our results revealed an atypical mammalian sperm structure with spermatozoa from breeding, subordinate and disperser males being degenerate and almost completely lacking a "mammalian phylogenetic stamp". Sperm structure is characterized by extreme polymorphism with most spermatozoa classified as abnormal. Sperm head shapes include round, oval, elongated, lobed, asymmetrical and amorphous. At the ultrastructural level, the sperm head contains condensed to granular chromatin with large open spaces between the chromatin. Nuclear chromatin seems disorganized since chromatin condensation is irregular and extremely inconsistent. The acrosome forms a cap (ca 35%) over the anterior part of the head. A well defined nuclear fossa and neck with five minor sets of banded protein structures are present. The midpiece is poorly organized and contains only 5 to 7 round to oval mitochondria. The flagellar pattern is 9+9+2. A distinct degenerative feature of the tail principal piece is the absence of the fibrous sheath. Only 7% motile spermatozoa were observed which had exceptionally slow swimming speeds. In this species, sperm form has simplified and degenerated in many aspects and represents a specialised form of degenerative Orthogenesis at the cellular level.
Gregory Sullivan - One of the best experts on this subject based on the ideXlab platform.
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The Instinctual Nation-State: Non-Darwinian Theories, State Science and Ultra-Nationalism in Oka Asajirō’s Evolution and Human Life
Journal of the History of Biology, 2011Co-Authors: Gregory SullivanAbstract:In his anthology of socio-political essays, Evolution and Human Life , Oka Asajirō (1868–1944), early twentieth century Japan’s foremost advocate of evolutionism, developed a biological vision of the nation-state as super-organism that reflected the concerns and aims of German-inspired Meiji statism and anticipated aspects of radical ultra-nationalism. Drawing on non-Darwinian doctrines, Oka attempted to realize such a fused or organic state by enhancing social instincts that would bind the minzoku (ethnic nation) and state into a single living entity. Though mobilization during the Russo-Japanese War seemed to evince this super-organism, the increasingly contentious and complex society that emerged in the war’s aftermath caused Oka to turn first to Lamarckism and eventually to Orthogenesis in the hopes of preserving the instincts needed for a viable nation-state. It is especially in the state interventionist measures that Oka finally came to endorse in order to forestall orthogenetically-driven degeneration that the technocratic proclivities of his statist orientation become most apparent. The article concludes by suggesting that Oka’s emphasis on degeneration, autarkic expansion, and, most especially, totalitarian submersion of individuals into the statist collectivity indicates a complex relationship between his evolutionism and fascist ideology, what recent scholarship has dubbed radical Shinto ultra-nationalism.
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The instinctual nation-state: non-Darwinian theories, state science and ultra-nationalism in Oka Asajirō's Evolution and Human Life.
Journal of the history of biology, 2010Co-Authors: Gregory SullivanAbstract:In his anthology of socio-political essays, Evolution and Human Life, Oka Asajirō (1868–1944), early twentieth century Japan’s foremost advocate of evolutionism, developed a biological vision of the nation-state as super-organism that reflected the concerns and aims of German-inspired Meiji statism and anticipated aspects of radical ultra-nationalism. Drawing on non-Darwinian doctrines, Oka attempted to realize such a fused or organic state by enhancing social instincts that would bind the minzoku (ethnic nation) and state into a single living entity. Though mobilization during the Russo-Japanese War seemed to evince this super-organism, the increasingly contentious and complex society that emerged in the war’s aftermath caused Oka to turn first to Lamarckism and eventually to Orthogenesis in the hopes of preserving the instincts needed for a viable nation-state. It is especially in the state interventionist measures that Oka finally came to endorse in order to forestall orthogenetically-driven degeneration that the technocratic proclivities of his statist orientation become most apparent. The article concludes by suggesting that Oka’s emphasis on degeneration, autarkic expansion, and, most especially, totalitarian submersion of individuals into the statist collectivity indicates a complex relationship between his evolutionism and fascist ideology, what recent scholarship has dubbed radical Shinto ultra-nationalism.
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Tricks of transference: Oka Asajirō (1868-1944) on Laissez-faire capitalism.
Science in context, 2010Co-Authors: Gregory SullivanAbstract:ArgumentContrary to common portrayals of social Darwinism as a transference of laissez-faire values, the widely read evolutionism of Japan's foremost Darwinist of the early twentieth-century, Oka Asajirō (1868–1944), reflects a statist outlook that regards capitalism as the beginning of the nation's degeneration. The evolutionary theory of Orthogenesis that Oka employed in his 1910 essay, “The Future of Humankind,” links him to a pre-Darwinian idealist tradition that depicted the state as an organism that develops through life-cycle stages. For Oka, laissez-faire capitalism marked the moment when the state began to decline toward extinction due to the orthogenetic overdevelopment of hitherto subordinate individual egos. Because conservative bureaucrat-intellectuals had been drawing upon this same organicist-developmental tradition since the 1880s in an attempt to forestall the social ills of industrialism, Oka's call for statist measures, including eugenics, to lessen and delay the atomizing, enervating, and corrupting influence of capitalism articulated the political vision of officialdom. Statist evolutionism, not social Darwinism, might be the term that best describes Oka's approach.
Gerhard Van Der Horst - One of the best experts on this subject based on the ideXlab platform.
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Sperm structure and motility in the eusocial naked mole-rat, Heterocephalus glaber: a case of degenerative Orthogenesis in the absence of sperm competition?
BMC evolutionary biology, 2011Co-Authors: Gerhard Van Der Horst, Liana Maree, Sanet H. Kotzé, M. Justin O'riainAbstract:We have studied sperm structure and motility in a eusocial rodent where reproduction is typically restricted to a single male and behaviourally dominant queen. Males rarely compete for access to the queen during her estrus cycle, suggesting little or no role for sperm competition. Our results revealed an atypical mammalian sperm structure with spermatozoa from breeding, subordinate and disperser males being degenerate and almost completely lacking a "mammalian phylogenetic stamp". Sperm structure is characterized by extreme polymorphism with most spermatozoa classified as abnormal. Sperm head shapes include round, oval, elongated, lobed, asymmetrical and amorphous. At the ultrastructural level, the sperm head contains condensed to granular chromatin with large open spaces between the chromatin. Nuclear chromatin seems disorganized since chromatin condensation is irregular and extremely inconsistent. The acrosome forms a cap (ca 35%) over the anterior part of the head. A well defined nuclear fossa and neck with five minor sets of banded protein structures are present. The midpiece is poorly organized and contains only 5 to 7 round to oval mitochondria. The flagellar pattern is 9+9+2. A distinct degenerative feature of the tail principal piece is the absence of the fibrous sheath. Only 7% motile spermatozoa were observed which had exceptionally slow swimming speeds. In this species, sperm form has simplified and degenerated in many aspects and represents a specialised form of degenerative Orthogenesis at the cellular level.
Igor Popov - One of the best experts on this subject based on the ideXlab platform.
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Mystics or Unrealised Synthesis
Orthogenesis versus Darwinism, 2018Co-Authors: Igor PopovAbstract:Orthogenesis has often been accused of “mystics”, “vitalism”, “teleology” etc. but these accusations were little more than insults used in polemics on evolutionary issues. The main reason why Orthogenesis is inconvenient and unpopular is that it places unsolved issues at the centre of the evolutionary concept. The complexity of biological phenomena, which cannot be explained in their entirety by the modern synthesis, keeps attracting new researchers.
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Declarations in Favour of Orthogenesis in the 1900–1930s
Orthogenesis versus Darwinism, 2018Co-Authors: Igor PopovAbstract:The ideas of directed evolution were especially popular in palaeontology. They were also supported by idealistic morphologists, who described “typological affinities” of biological structures without analysing either their origin or their adaptive significance. This analysis revealed morphological regularities, which were used as arguments in favour of Orthogenesis. Some taxonomists, zoologists, botanists, geneticists, biochemists also supported Orthogenesis at that time, criticising the adaptationistic paradigm and revealing certain laws of variation and evolution. Some of their arguments still seem convincing.
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Statements in Support of Orthogenesis in the 1950s and Later
Orthogenesis versus Darwinism, 2018Co-Authors: Igor PopovAbstract:In addition to new or revived ideas related with Orthogenesis, there were in the recent history of evolutionary biology many statements in its support. Russian sources are especially interesting in this respect because in the Soviet Russia Darwinism occupied the same place in biology as communism did in society. Orthogenesis was in contrast with official ideology, and its support was fraught with serious problems. Yet orthogenetic heresy surfaced in the Soviet Union with a persistence that seems to indicate the solidity of its argumentation base. A similar phenomenon—the emergence of orthogenetic ideas under condition of dominating Darwinism—can also be seen in other countries. Though ideological pressure on biology was less dramatic there, non-Darwinian concepts were also considered as somewhat heretic—and yet they kept emerging.
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Orthogenesis and the Modern Evolutionary Synthesis
Orthogenesis versus Darwinism, 2018Co-Authors: Igor PopovAbstract:The modern evolutionary synthesis, also referred to as the modern Darwinism, was formed in the 1930–40s and has dominated biology ever since. Its success is partly due to the energetic claims of its authors that they had solved all the main problems of the evolutionary biology. The modern Darwinism was formed over a long period of time by many scientists. This circumstance was both its weakness and its strength. On the one hand, the vagueness of its main postulates left it open to criticism. On the other hand, so much was written about this theory that most critical remarks could be addressed by finding a reference to some concession, exception or particular case.
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Direct Impact of the Environment on Evolution and the Inheritance of Acquired Characteristics
Orthogenesis versus Darwinism, 2018Co-Authors: Igor PopovAbstract:Speculations about a direct effect of the environment on evolutionary changes are closely associated with Orthogenesis because accusations of Lamarckism were have often been directed at its supporters. At the same time, the ideas of Lamarck and his followers were discredited by the idea of the “inheritance of acquired characteristics”. This seems to be a firmly established fallacy. Lamarck indeed wrote about exercises and action of the environment upon evolution but never used the terms “heredity” or “inheritance”.
Sanet H. Kotzé - One of the best experts on this subject based on the ideXlab platform.
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Sperm structure and motility in the eusocial naked mole-rat, Heterocephalus glaber: a case of degenerative Orthogenesis in the absence of sperm competition?
BMC evolutionary biology, 2011Co-Authors: Gerhard Van Der Horst, Liana Maree, Sanet H. Kotzé, M. Justin O'riainAbstract:We have studied sperm structure and motility in a eusocial rodent where reproduction is typically restricted to a single male and behaviourally dominant queen. Males rarely compete for access to the queen during her estrus cycle, suggesting little or no role for sperm competition. Our results revealed an atypical mammalian sperm structure with spermatozoa from breeding, subordinate and disperser males being degenerate and almost completely lacking a "mammalian phylogenetic stamp". Sperm structure is characterized by extreme polymorphism with most spermatozoa classified as abnormal. Sperm head shapes include round, oval, elongated, lobed, asymmetrical and amorphous. At the ultrastructural level, the sperm head contains condensed to granular chromatin with large open spaces between the chromatin. Nuclear chromatin seems disorganized since chromatin condensation is irregular and extremely inconsistent. The acrosome forms a cap (ca 35%) over the anterior part of the head. A well defined nuclear fossa and neck with five minor sets of banded protein structures are present. The midpiece is poorly organized and contains only 5 to 7 round to oval mitochondria. The flagellar pattern is 9+9+2. A distinct degenerative feature of the tail principal piece is the absence of the fibrous sheath. Only 7% motile spermatozoa were observed which had exceptionally slow swimming speeds. In this species, sperm form has simplified and degenerated in many aspects and represents a specialised form of degenerative Orthogenesis at the cellular level.
