What is Two Kingdoms Classification?
It is defined as a Kingdom Plantae and Kingdom Animalia. Kingdom Plantae included Plants which had cell wall, inorganic crystals, no excretory organs, to make their own food, no locomotion and muscular tissue etc. Kingdom Animalia included animals which have opposite features as compared to Kingdom Plantae.
Many objections were raised regarding this classification as it was not able to meet many criteria’s. As there was no separate group for organisms like fungi, lichen planus, slime moulds. There were many organisms in which differentiation of plants and animals was difficult to predict. For example euglena had mixotrophic nutrition. Some of organisms like viruses, prokaryotes and eukaryotes have large difference in their volume range and they were placed in the same group. Prokaryotes had genetic material which was disorganized without any meiosis or sexual reproduction. On contrary eukaryotes had organized nuclear structure and a proper sexual reproduction. Yet they were placed in the same group.
What is Three Kingdom Classification?
Heckel gave three kingdom classifications. It was based upon the lack of tissue differentiation. A new group Protista was added into the already present groups. Kingdom Protista consisted of unicellular organisms.
What is Four Kingdom Classification?
It is entirely based on nuclear structure and a new group Monera was added into previously existing groups (plants, animals and protista). Copeland created it.
What is Five Kingdom Classification?
It was given by R.H Whittaker in 1969. He included Kingdom Fungi among all the various Kingdoms. His criteria were based upon cell structure, body structure, mode of nutrition and relationships including ecological life style. Viruses were excluded as their living status was controversial.
