Who proposed the six-kingdom classification?
Carl Woese
In the past, knowledge about the peculiarities of microorganisms like bacteria was limited. Later it was found that the archaebacteria belonging to the kingdom Monera are different from the other bacteria in cell structure and physiological functions. Then, kingdom Monera was further divided into 2 kingdoms namely: Archeae and Bacteria. Beside this one more level of classification named domain was added above the kingdom. It was American scientist Carl Woese who proposed six-kingdom classification.