Changes

== History ==

== History ==

 

The endosymbiotic theory was first articulated by famed [[Russian]] botanist Konstantin Mereschkowski in 1905<ref>Mereschkowski C (1905). "Über Natur und Ursprung der Chromatophoren im Pflanzenreiche". Biol Centralbl 25: 593–604.</ref>. Mereschkowski based his theory in part on work done by botanist Andreas Schimper, who had observed in 1883 that the division of chloroplasts in green [[plants]] closely resembled that of cyanobacteria. Schimper had himself tentatively proposed (in a footnote) that green plants could have arisen from the symbiosis of two simpler organisms.<ref>Schimper AFW (1883). "Über die Entwicklung der Chlorophyllkörner und Farbkörper". Bot. Zeitung 41: 105–14, 121–31, 137–46, 153–62.</ref> In the 1920s, Irvin Wallin, a [[professor]] at the University of Colorado Medical School, extended the idea of an endosymbiotic origin to the mitochondria.<ref>Wallin IE (1923). "The Mitochondria Problem". The American Naturalist 57 (650): 255–61. doi:10.1086/279919.

The endosymbiotic theory was first articulated by famed [[Russian]] botanist Konstantin Mereschkowski in 1905<ref>Mereschkowski C (1905). "Über Natur und Ursprung der Chromatophoren im Pflanzenreiche". Biol Centralbl 25: 593–604.</ref>. Mereschkowski based his theory in part on work done by botanist Andreas Schimper, who had observed in 1883 that the division of chloroplasts in green [[plants]] closely resembled that of cyanobacteria. Schimper had himself tentatively proposed (in a footnote) that green plants could have arisen from the symbiosis of two simpler organisms.<ref>Schimper AFW (1883). "Über die Entwicklung der Chlorophyllkörner und Farbkörper". Bot. Zeitung 41: 105–14, 121–31, 137–46, 153–62.</ref> In the 1920s, Irvin Wallin, a [[professor]] at the University of Colorado Medical School, extended the idea of an endosymbiotic origin to the mitochondria.<ref>Wallin IE (1923). "The Mitochondria Problem". The American Naturalist 57 (650): 255–61. doi:10.1086/279919.

</ref> These theories were initially dismissed (or ignored) by the scientific community. More detailed electron microscopic comparisons between cyanobacteria and chloroplasts (for example, studies by Hans Ris<ref>Ris H, Singh RN (January 1961). "Electron microscope studies on blue-green algae". J Biophys Biochem Cytol 9 (1): 63–80. doi:10.1083/jcb.9.1.63. PMC 2224983. PMID 13741827.</ref>) combined with the discovery that plastids and mitochondria contain their own [[DNA]]<ref>Stocking C and Gifford E (1959). "Incorporation of thymidine into chloroplasts of Spirogyra". Biochem. Biophys. Res. Comm. 1 (3): 159–64. doi:10.1016/0006-291X(59)90010-5.

</ref> These theories were initially dismissed (or ignored) by the scientific community. More detailed electron microscopic comparisons between cyanobacteria and chloroplasts (for example, studies by Hans Ris<ref>Ris H, Singh RN (January 1961). "Electron microscope studies on blue-green algae". J Biophys Biochem Cytol 9 (1): 63–80. doi:10.1083/jcb.9.1.63. PMC 2224983. PMID 13741827.</ref>) combined with the discovery that plastids and mitochondria contain their own [[DNA]]<ref>Stocking C and Gifford E (1959). "Incorporation of thymidine into chloroplasts of Spirogyra". Biochem. Biophys. Res. Comm. 1 (3): 159–64. doi:10.1016/0006-291X(59)90010-5.

</ref> (which had recently been identified as the hereditary material of organisms) led to a resurrection of the idea in the 1960s.  

</ref> (which had recently been identified as the hereditary material of organisms) led to a resurrection of the idea in the 1960s.  

 

The endosymbiotic hypothesis was advanced and substantiated with [[microbiology|microbiological]] evidence in 1967 by [[American]] biologist Lynn Margulis. A young faculty member at [[Boston University]], Margulis authored a theoretical paper entitled ''The Origin of Mitosing Eukaryotic Cells''<ref>Lynn Sagan (1967). "On the origin of mitosing cells". J Theor Bio. 14 (3): 255–274. doi:10.1016/0022-5193(67)90079-3. PMID 11541392.</ref>. The paper, however, was "rejected by about fifteen scientific journals," Margulis recalled<ref>John Brockman, The Third Culture, New York: Touchstone, 1995, 135.</ref>. It was finally accepted by ''The Journal of Theoretical Biology'' and is considered today a landmark in modern endosymbiotic theory. Drawing heavily from the ideas of Mereschkowski and Wallin, Margulis's endosymbiotic theory formulation is the first to rely on direct microbiological observations as opposed to [[paleontology|paleontological]] or [[zoology|zoological]] observations, which were previously the norm for new works in [[evolutionary biology]].  

The endosymbiotic hypothesis was advanced and substantiated with [[microbiology|microbiological]] evidence in 1967 by [[American]] biologist Lynn Margulis. A young faculty member at [[Boston University]], Margulis authored a theoretical paper entitled ''The Origin of Mitosing Eukaryotic Cells''<ref>Lynn Sagan (1967). "On the origin of mitosing cells". J Theor Bio. 14 (3): 255–274. doi:10.1016/0022-5193(67)90079-3. PMID 11541392.</ref>. The paper, however, was "rejected by about fifteen scientific journals," Margulis recalled<ref>John Brockman, The Third Culture, New York: Touchstone, 1995, 135.</ref>. It was finally accepted by ''The Journal of Theoretical Biology'' and is considered today a landmark in modern endosymbiotic theory. Drawing heavily from the ideas of Mereschkowski and Wallin, Margulis's endosymbiotic theory formulation is the first to rely on direct microbiological observations as opposed to [[paleontology|paleontological]] or [[zoology|zoological]] observations, which were previously the norm for new works in [[evolutionary biology]].