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Symbiogenesis
Symbiogenesis (endosymbiotic theory, or serial endosymbiotic theory,) is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes (more closely related to the Bacteria than to the Archaea) taken one inside the other in endosymbiosis. Mitochondria appear to be phylogenetically related to Rickettsiales bacteria, while chloroplasts are thought to be related to cyanobacteria. The idea that chloroplasts were originally independent organisms that merged into a symbiotic relationship with other one-celled organisms dates back to the 19th century, when it was espoused by researchers such as Andreas Schimper. The endosymbiotic theory was articulated in 1905 and 1910 by the Russian botanist Konstantin Mereschkowski, and advanced and substantiated with microbiological evidence by Ly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boris Kozo-Polyansky
Boris Mikhailovich Kozo-Polyansky (; 20 January 1890 – 21 April 1957) was a Soviet and Russian botanist and evolutionary biologist, best known for his seminal work, ''Symbiogenesis: A New Principle of Evolution'', which was the first work to place the theory of symbiogenesis into a Darwinian evolutionary context, as well as one of the first to redefine cell theory. Life Boris Kozo-Polyansky was born in Ashgabat, which at the time was part of the Russian Empire. He relocated to Voronezh in his early youth.Prokhorov, A. M. (Aleksandr Mikhaĭlovich). Great Soviet Encyclopedia. New York: Macmillan, 1973. He graduated from Moscow University in 1914 at the age of 24, before returning to Voronezh where he worked as an assistant at Voronezh Agricultural University until 1918. In 1920 he then became a professor at Voronezh State University, where he taught for the remainder of his life and served as a Dean, Chair of Botany and Vice President of the University. He is buried in Voronezh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbiogenesis
Symbiogenesis (endosymbiotic theory, or serial endosymbiotic theory,) is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes (more closely related to the Bacteria than to the Archaea) taken one inside the other in endosymbiosis. Mitochondria appear to be phylogenetically related to Rickettsiales bacteria, while chloroplasts are thought to be related to cyanobacteria. The idea that chloroplasts were originally independent organisms that merged into a symbiotic relationship with other one-celled organisms dates back to the 19th century, when it was espoused by researchers such as Andreas Schimper. The endosymbiotic theory was articulated in 1905 and 1910 by the Russian botanist Konstantin Mereschkowski, and advanced and substantiated with microbiological evidence by Ly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Konstantin Mereschkowski
Konstantin Sergeevich Mereschkowski ( rus, Константи́н Серге́евич Мережко́вский, p=mʲɪrʲɪˈʂkofskʲɪj; – 9 January 1921) was a prominent Russian biologist and botanist, active mainly around Kazan, Tatarstan, whose research on lichens led him to propose the theory of symbiogenesis – that larger, more complex cells (of eukaryotes) evolved from the symbiotic relationship between less complex ones. He presented this theory in 1910, in his work, ''The Theory of Two Plasms as the Basis of Symbiogenesis, a New Study of the Origins of Organisms'', although the fundamentals of the idea had already appeared in his earlier 1905 work, ''The nature and origins of chromatophores in the plant kingdom''. Biography Early life Konstantin was born in Saint Petersburg, one of six sons and three daughters in the Mereschkowski family. His father Sergey Ivanovich served as a senior official in several Russian local governors' cabinets (including tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lynn Margulis
Lynn Margulis (born Lynn Petra Alexander; March 5, 1938 – November 22, 2011) was an American evolutionary biologist, and was the primary modern proponent for the significance of symbiosis in evolution. Historian Jan Sapp has said that "Lynn Margulis's name is as synonymous with symbiosis as Charles Darwin's is with evolution." In particular, Margulis transformed and fundamentally framed current understanding of the evolution of cells with nuclei – an event Ernst Mayr called "perhaps the most important and dramatic event in the history of life" – by proposing it to have been the result of symbiotic mergers of bacteria. Margulis was also the co-developer of the Gaia hypothesis with the British chemist James Lovelock, proposing that the Earth functions as a single self-regulating system, and was the principal defender and promulgator of the five kingdom classification of Robert Whittaker. Throughout her career, Margulis' work could arouse intense objection (one grant applic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryotic
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosymbiont
An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within", σύν ''syn'' "together" and βίωσις ''biosis'' "living".) Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root nodules of legumes, single-cell algae inside reef-building corals and bacterial endosymbionts that provide essential nutrients to insects. There are two types of symbiont transmissions. In horizontal transmission, each new generation acquires free living symbionts from the environment. An example is the nitrogen-fixing bacteria in certain plant roots. Vertical transmission takes place when the symbiont is transferred directly from parent to offspring. It is also possible for both to be involved in a mixed-mode transmission, where symbionts are transferred vertically for some generation bef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Portier (physiologist)
Paul Jules Portier (22 May 1866 – 26 January 1962) was a French physiologist who made important contributions to the discovery of anaphylaxis and the development of symbiogenesis. On a scientific expedition organised by Albert I, Prince of Monaco, he and Charles Richet discovered that toxins produced by marine animals (cnidarians such as Portuguese man o' war and sea anemone) could induce fatal shocks. They named the medical phenomenon "anaphylaxis," from which Richet went on to receive the 1913 Nobel Prize in Physiology or Medicine. Portier was the first scientist to explain that the cell organelle, mitochondrion, arose by symbiosis according to his evolutionary theory in 1818. Biography Portier was born in Bar-sur-Seine, France, to Ernest Paul and Julie Moreau Laure. He studied elementary education at the Lycée de Troyes from 1878 to 1885. After passing the final secondary examination (called ''bac'') from the Saint-Sigisbert in Nancy, he qualified for service in the Minis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondria
A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'' was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A large number of unicellular organisms, such as microsporidia, parabasalids and diplomonads, have reduced or transformed their mitochondria into mitosome, other structures. One eukaryote, ''Monocercomonoides'', is known to have completely lost its mitocho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrion
A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'' was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A large number of unicellular organisms, such as microsporidia, parabasalids and diplomonads, have reduced or transformed their mitochondria into other structures. One eukaryote, ''Monocercomonoides'', is known to have completely lost its mitochondria, and one multicellular organism, '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ivan Wallin
Ivan Emanuel Wallin (22 January 1883 – 6 March 1969) was an American biologist who made the first experimental works on endosymbiotic theory. Nicknamed the "Mitochondria Man", he claimed that mitochondria, which are cell organelles, were once independent bacteria, as supported by his comparative studies and culture of isolated mitochondria. From 1922, he published a series of papers titled "On the nature of mitochondria" in the '' American Journal of Anatomy'' which became the experimental foundations of his claims. He was the first person to specifically postulate that eukaryotic organelles originated from bacteria, and that symbiosis is a major force in creation of new species. Wallin was Professor of Anatomy at the University of Colorado Medical School. He was noted for his eccentric life in academia, such as his preference for exclusively practical demonstration rather than lecturing, his frequent parties for students and an annual Christmas glögg party. Biography Wal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of ''Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andreas Franz Wilhelm Schimper
Andreas Franz Wilhelm Schimper (12 May 1856 – 9 September 1901) was a German botanist and phytogeographer who made major contributions in the fields of histology, ecology and plant geography. He travelled to South East Asia and the Caribbean as part of the 1899 deep-sea expedition. He coined the terms tropical rainforest and sclerophyll and is commemorated in numerous specific names. Biography Schimper was born in Strassburg, (present day Strasbourg, France), into a family of eminent scientists. His father Wilhelm Philippe Schimper (1808-1880) was Director of the Natural History Museum in the same town, Professor of Geology, and a leading bryologist. His father's cousin was Georg Wilhelm Schimper (1804-1878), prominent collector and explorer in Arabia and North Africa; the naturalist Karl Friedrich Schimper was also a relative. Schimper studied at the University of Strassburg from 1874 to 1878, acquiring a Ph.D. He then worked in Lyon, and in 1880 travelled to the United ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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