In Classification of Plant Kingdoms the Fourth Kingdom Classification was given by Copeland an American biologist who created the fourth kingdom Mycota (Monera) along with Three Kingdoms. In 1966, he included bacteria and one of the most primitive algae, called blue green algae, under this kingdom.

Copeland was the first scientist who separated bacteria into a separate kingdom known as Monera.

Classification of Plant Kingdoms: Five Kingdom Classification

Five Kingdom Classification was proposed by an America plant ecologist Robert Harding Whittaker. He gave kingdom Fungi along with other four kingdoms.

Criteria for the Basis of Five Kingdom Classification

These are above mentioned criteria’s, which were used by Robert Harding Whittaker for determining Five Kingdom Classification.

Complexity of cell structure, means either organism is Eukaryotic or Prokaryotic. Complexity of cell body, the organism is Unicellular or Multicellular. Reproduction, whether it is sexual or asexual. Mode of Nutrition, that whether the organism is Autotrophic in Nature of Heterotrophic in Nature. Mode of Nutrition was the most important criteria. Last one criteria, which was not used by any other classification system till now, was phylogenetic Analysis/Evolutionary Relationship.

How the new organisms derived from preexisting organisms? Or How the evolution has occurred?

Means which organism is Primitive, which organism is Advanced.

Distinguishing of organism by using Evolutionary Relationship.

Mode of Nutrition in Fungi Kingdom Further Classified

Comparative Study of Five Kingdoms

Now we discuss the comparative study of five kingdom with respect criteria characteristics

Monera Protists Fungi Plantae Animalia Cell Type Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic Cell Wall Present (Peptidoglycan) Present (Non-Cellulose) Present (Chitin) Present (Cellulosic) Absent Nuclear Membrane Absent Present Present Present Present Body Organization Unicellular Unicellular Mainly Multicellular, with Mycelium, tissue (Without True Tissue) Tissue/Organ Level of Organization [Tissue, Organ, Organ System] Level of Organization Nutrition Autotrophic 1.Photoautotrophic (Making food by using light energy) 2.Chemoautotrophic (Making food by using chemical energy) Heterotrophic 1.Parasitic 2.Saprotrophic Autotrophic 1.Photoautotrophic (Making food by using light energy) Heterotrophic 1.Parasitic 2.Saprotrophic 3.Holozoic Heterotrophic 1.Parasitic 2.Saprotrophic Autotrophic 1.Photoautotrophic (Making food by using light energy) Heterotrophic 1.Parasitic 2.Holozoic

Drawbacks of Five Kingdom Classification System, the positive points of classification that are very much clear and are distinguished as

Drawbacks of Five Kingdom Classification

The first drawback of five kingdom classification system is as follow

So, utilizing the Linnaeus classification system, all algae were placed into kingdom plantae but according to Whittaker algae were divided into three kingdoms (Monera, Protista, Plantae).

Viruses, they were not given the position into anyone kingdom.

Classification of Plant Kingdoms: The Six Kingdom Classification System

Six kingdom Classification was given by Carl Woese. He divided the kingdom Monera into two kingdoms.

Criteria for the Basis of Six Kingdom Classification

The criteria used by Carl for the basis of Six Kingdom System is as follow:

Genetic Analysis

Carl proposed genetic analysis of different organisms, which are present in different kingdoms (Plantae, Protista, Fungi, Animalia) by using chemical 16Sr RNA gene.

He used 16Sr gene because of its ability to synthesize 16Sr RNA. “S” represents sedimentation co-efficient.

After studying gene sequence, he concluded that six kingdoms can be grouped under these three categories, which named as Domains.

This shows that Carl proposed these three Domains and Six Kingdoms on the basis of Genetic Analysis.

Just like Whittaker this system is also based upon Evolutionary Relationship.