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. |