top of page
Gurugrah Questions: Your Source for Thoughtful Queries, Your Gateway to Enlightening Answers.

  Instant Answers to The Questions! 

Sequence No.

BIO-2221

What is five kingdom system of classification. Mention drawbacks of five kingdoms system of classification.

 

Answer:

R.H. Whittaker, an American ecologist proposed a five kingdom system of classification in 1969. The kingdoms defined by him were named Monera, Protista, Fungi, Plantae and Animalia. The main criteria for classification used by him include cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships.
Basic features of Five Kingdom Classification:
1. Structure of Cells: Organisms can be divided into two major categories on the basis of cell structure:

 

  1. Prokaryotic cells: having incipient nucleus and
  2. Eukaryotic cells: having membrane bounded nucleus and cell organelles.

 

2. Body Organisation: The theory of organic evolution has revealed that the earliest organisms were simple unicellular. Some of the unicellular prokaryotic organisms in due course of time evolved into multicellular organisms. Some of the multicellular organisms finally became complex.

3. Mode of Nutrition: R.H. Whittakar classified organisms on the basis of autotrophic and heterotrophic mode of nutrition. Autotrophic mode of nutrition can be divided into chemosynthetic nutrition and photosynthetic nutrition. Heterotrophic organisms are also divided into two categories: holozoic or ingestive and saprotrophic or absorptive.

4. Phylogenetic Relationships: Evolutionary history of an organism is called phylogeny. Therefore, phylogenetic relationships of organisms alone are the index of their true kinship. Such relationships are not clear in all cases. Only fossil record can provide such relationships but this record is incomplete and is likely to remain so. Therefore, the phylogenetic relationships are ascertained from morphology, cytology, genetics, biochemistry and physiology for the correct classification of living organisms.

Drawbacks of five kingdom system of classification:

 

  1. The kingdoms monera and protista are still heterogenous groups of organisms. Both include photosynthetic and heterotrophic organisms with cellwall and without cellwall.
  2. In this system of classification phylogenetic relationship particularly of lower organisms are not fully reflected, e.g., some green algae and some photosynthetic bacteria get hydrogen from sources other than H2O but these are grouped under different kingdoms.
  3. Each kingdom is polyphyletic. For example, many different protistian lives gave rise to multicellular group and none of the these higher kingdoms contains the single ancestor of all its members. Multicellular lives originated from protists many times.
  4. Unicellular green algae, such as Chlamydomonas, volvox have not been grouped in the kindgom protista due to their resemblence with the other green algae in structure, reproduction and pattern of life cycle.
  5. The slime moulds are quite different from the other protists with which they have been combined.
School Integrated Learning Programmes.png

Reporting Question Sequence No.

BIO-2221

Your Report Has Been Successfully Submitted.

Our Team Will Review It Shortly. Thank You for Your Contribution to our Knowledge Hub!

An error occurred. Try again later

Right-click disabled. For assistance, contact Gurugrah Help Center "gurugrah.in/help-center"
bottom of page