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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 Lyn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbiogenesis 2 Mergers
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 endosymbiont, endosymbiosis. Mitochondria appear to be phylogeny, 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 microbiolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Konstantin Mereschkowski
Konstantin Sergeevich Mereschkowski ( rus, Константи́н Серге́евич Мережко́вский, p=mʲɪrʲɪˈʂkofskʲɪj; – 9 January 1921) was a Russian biologist and botanist, active mainly around Kazan, 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 that of I.D. Talyzin ... [...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 symbiogenesis, symbiosis in evolution. In particular, Margulis transformed and fundamentally framed current understanding of the evolution of Eukaryote, cells with nuclei 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 kingdoms, five kingdom classification of Robert Whittaker (ecologist), Robert Whittaker. Throughout her career, Margulis' work could arouse intense objections, and her formative paper, "On the Origin of Mitosing Cells", appeared in 1967 after being rejected by about fifteen journals. Still a junior faculty member at Boston University at t ... [...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 1918. 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 Lycée Notre-Dame Saint-Sigisbert, Saint-Sigisbert in Nancy, h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondria
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'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal '' Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number of unicellular organisms, such as microspo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which capture the Radiant energy, energy from sunlight and convert it to chemical energy and release oxygen. The chemical energy created is then used to make sugar and other organic molecules from carbon dioxide in a process called the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in some unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. Chloroplasts are highly dynamic—they circulate and are moved around within cells. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts cannot be made anew by the plant cell and must ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutualism (biology)
Mutualism describes the ecological Biological interaction, interaction between two or more species where each species has a net benefit. Mutualism is a common type of Ecology, ecological interaction. Prominent examples are: * the nutrient exchange between vascular plants and mycorrhizal fungi, * the Fertilisation, fertilization of flowering plants by pollinators, * the ways plants use fruits and edible seeds to encourage animal aid in seed dispersal, and * the way corals become photosynthetic with the help of the microorganism zooxanthellae. Mutualism can be contrasted with interspecific competition, in which each species experiences ''reduced'' fitness, and Cheating (biology), exploitation, and with parasitism, in which one species benefits at the expense of the other. However, mutualism may evolve from interactions that began with imbalanced benefits, such as parasitism. The term ''mutualism'' was introduced by Pierre-Joseph van Beneden in his 1876 book ''Animal Parasites an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ) is a Domain (biology), domain of organisms. Traditionally, Archaea only included its Prokaryote, prokaryotic members, but this has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even though the domain Archaea Cladistics, cladistically includes eukaryotes, the term "archaea" (: archaeon , from the Greek "ἀρχαῖον", which means ancient) in English still generally refers specifically to prokaryotic members of Archaea. Archaea were initially Taxonomy (biology), classified as bacteria, receiving the name archaebacteria (, in the Archaebacteria Kingdom (biology), kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from Bacteria and Eukaryote, Eukaryota. Archaea are further divided into multiple recognized phylum, phyla. Classification is difficult because most have not been Isolation (microbiology), isolated in a laboratory and have been detected only by their Gene, gene s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosymbiont
An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualism (biology), mutualistic relationship. Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root nodules of legumes, single-cell algae inside Coral reef, reef-building corals, and bacterial endosymbionts that provide essential nutrients to insects. Endosymbiosis played key roles in the development of eukaryotes and plants. Roughly 2.2 billion years ago an archaeon absorbed a bacterium through phagocytosis, that eventually became the mitochondria that provide energy to almost all living Eukaryote, eukaryotic cells. Approximately 1 billion years ago, some of those cells absorbed cyanobacteria that eventually became chloroplasts, organelles that produce energy from sunlight. Approximately 100 million years ago, a lineage of amoeba in the genus ''Paulinella'' independently engulfed a cyanobacterium that evolved to be f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryotic
The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of Outline of life forms, life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal Kingdom (biology), kingdom Asgard (Archaea), Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as Flagellated cell, flagellated cells. The leading evolutiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbiosis
Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biological interaction, between two organisms of different species. The two organisms, termed symbionts, can for example be in Mutualism (biology), mutualistic, commensalism, commensalistic, or parasitism, parasitic relationships. In 1879, Heinrich Anton de Bary defined symbiosis as "the living together of unlike organisms". The term is sometimes more exclusively used in a restricted, mutualistic sense, where both symbionts contribute to each other's subsistence. This means that they benefit each other in some way. Symbiosis can be ''obligate'' (or ''obligative''), which means that one, or both of the organisms depend on each other for survival, or ''facultative'' (optional), when they can also subsist independently. Symbiosis is also classified by physical attachment. Symbionts forming a single body live ... [...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 Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
