what are the advantages and disadvantages of five kingdom classification?
Answers
In order to develop a proper phylogenetic classification, prominent scientist and an American taxonomist R.H. Whittaker (in 1969) developed and divided all the organisms into five kingdoms, viruses being a borderline, collectively called Five Kingdom Classification (Was there from 1969 to its was last maintained till its withdrawal in 1990).
Advantages of Five Kingdom Classification:
1) The separation of prokaryotes in a separate kingdom of Monera is a wise step because procaryotes differ from all other organisms in their genetic, cellular, reproductive and physical including physiological Organisation.
2) There were many transitional or intermediate forms which were present in the unicellular eucaryotes which had been included both amongst the plants and the animals. Separation of every unicellular eucaryotes into kingdom Protista has completely removed this anomaly.
3) Kingdom Fungi have never been related to plants. They have their own biochemical, physical and structural Organisation which separates them from Kingdom Plantae. Separation of Fungi into their own separate kingdom was actually a long overdue.
4) The five kingdom classification was based on different levels of Organisation and nutrition which evolved very early and became completely established in later groups which are now currently existing today.
5) In five kingdom classification, animal and plant kingdoms are more homogeneous than they are in precedence of two-kingdom classification.
6) This King Dom has successfully tried to bring out phylogenetic relationships even amongst the most primitive forms and species.
Disadvantages of the five kingdom classification:
1) Five kingdom classification of Whittaker has not been specific with the real terms of the phylogenetic classification system which clearly cannot be established till all the distinct evolutionary tendencies have been separated. This is not possible at a lowermost level, for a specific example, certain green algae have known to obtain hydrogen from sources other than water like photosynthetic bacteria have been applied to it. Similarly, for Euglena, it can be photosynthetic as well as, at the same time, saprotrophic in nature. Their relatives can have absorptive as well as some ingestive type of heterotropic nutrition.
2) A similar distinction between unicellular and multicellular organisms is not possible in this case of algae. It is because of this that the unicellular green algae have not been included into the kingdom of Protista by Whittaker.
3) Each specific group has an immense amount of diversity which is very difficult to keep it together in one same classification. For an example, Monera and Protista contain both the distinctive features of having walled and wall-less organisms, photosynthetic and nonphotosynthetic organisms, unicellular and filamentous or mycelial organisms.
4) Viruses, in particular, have not been included into this system of classification because of the deviation between the living and the nonliving organisms.
5) Archaebacteria completely differ in a large scale from other bacteria in structure, composition and physiological appearances.
6) Mycoplasmas or PPLO are quite different from a bacterium where they have been placed along with procaryotes.
The advantages of the five kingdom system of classification are the following:
1) It is the agreeable arrangement of division because phylogeny can simply be determined.
2) Prokaryotes are grouped in a separate domain as they have distinct organisation formation.
3) The unicellular bion is involved in Protista and resolves the difficulties of the place of Euglena.
4) Fungi are grouped in the separate domain as they are diverse from other embryonic Eukaryotas.
5) This arrangement of classification involves the formation of cell and forms of nourishment which appeared early through evolution.
The following are the disadvantages of the five kingdom system of classification:
1. It does not distinguish between various heterotrophic group (autotrophic green shoots and fungi).
2) There is no specifying of any acellular bions such as viroids, viruses and lichen.