Konstantin Mereschkowski

For his brother, a Russian writer, see Dmitry Merezhkovsky.

Konstantin Mereschkowski

Konstantin Mereschcowsky (1855–1921) (Template:Lang-ru, also transliterated Konstantin Sergeevich Merezhkovsky, Konstantin Sergivich Merezhkovsky, Constantin Sergeevič Mérejkovski, Constantin Sergejewicz Mereschcowsky, and Konstantin Sergejewicz Mereschkovsky) was a prominent Russian biologist, botanist, active mainly around Kazan, whose research on lichens led him to propose the theory of symbiogenesis – that larger, more complex cells evolved from the symbiotic relationship between less complex ones. He presented this theory in 1910, in his Russian work, The Theory of Two Plasms as the Basis of Symbiogenesis, a New Study or the Origins of Organisms, although the fundamentals of the idea already had appeared in his earlier 1905 work, The nature and origins of chromatophores in the plant kingdom.

He was inspired by his work as a leading lichenologist – lichens were of major interest at the time as it had recently been shown that they exhibit a symbiotic relationship between fungi and algae. Around the turn of the century he collected a sizeable lichen herbarium, containing over 2000 specimens from lands in Russia, Austria and around the Mediterranean. The collection is currently in the possession of Kazan University. He also studied hydras.

Merezhkovsky rejected Darwinian evolutionary theory. He did not believe that natural selection could explain biological novelty, positing instead the acquisition and inheritance of microbes as central. He was criticised by another Russian lichenologist, Alexandr Alexandrovich Elenkin.

Merezhovsky's ideas of symbiogenesis are reflected in the modern endosymbiotic theory developed and popularised by Lynn Margulis. In this, organelles such as chloroplasts and mitochondria are the descendants of bacteria that evolved into an intracellular symbiosis with early eukaryotic cells.

Merezhkovsky, also wrote utopian stories, such as The paradise on earth or a winter night dream.