Who came up with the endosymbiotic theory?
Like so many ideas, it was the result of the works of multiple people. It was proposed long before enough evidence could be gathered to support it. Konstantin Mereschkowski put forth the hypothesis for plants/chloroplasts in 1905 based on Schimper’s comment about similarity. Wallin extended the idea to mitochondria. Form alone was insufficient to make any conclusions. Lynn Margulis popularized the idea, and with the benefits of modern biology, the electron microscope and molecular biology, enough evidence was gathered to support the idea and promote it to a theory.
