Yes, biological classification is an ever evolving phenomenon.

• In the starting C. Linnaeus divided organisms into two kingdoms- Plantae and Animalia. This classification was based on the morphological characters.

• But later on it was realised that only two kingdoms were not sufficient because there were certain organisms which were claimed by both botanists and zoologists.

• This problem vanished when R.H. Whittaker proposed five kingdom classification system. Euglena and slime moulds were given place under kingdom Protista. Blue green algae and bacteria were been placed under Monera.

• In 1977 Carl Woese proposed six kingdom classification. In this classification the Kingdom Monera was splitted into two more domains i.e. Eubacteria and Archebacteria this was done on the basis of some major differences in cell wall.

Still the classification system is not complete because there are many organisms like viruse, virioids and prions which have not been classified under any kingdom. And many of the organisms are still waiting to be discovered and classified. Hence it can be said that the biological classification is ever evolving phenomenon.