Five Kingdom Classification

Question

When Whittaker proposed his five kingdom system in 1969, which principal criterion distinguished members of Kingdom Monera from those placed in Protista?

RankGuru · Accepted Answer

Robert Whittaker's 1969 five kingdom classification, detailed in NCERT Class 11, Chapter 2 (Biological Classification), used cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships as its criteria. The defining line between Monera and Protista is the cellular grade of organisation: Monera contains only prokaryotes, whose cells lack a true membrane-bound nucleus and membrane-bound organelles, whereas Protista comprises single-celled eukaryotes possessing a well-defined nucleus and organelles. Nutrition is not the separator because both kingdoms contain autotrophic and heterotrophic forms. Cell wall presence fails as a criterion since many monerans and several protists both have walls, while some lack them. Unicellularity versus multicellularity is incorrect because both kingdoms are predominantly unicellular, so this cannot distinguish them. The prokaryote–eukaryote divide is therefore the fundamental structural difference. A logical consistency check supports this: placing all prokaryotes in one kingdom and the simplest eukaryotes in another is precisely what gave Whittaker's scheme its improved evolutionary coherence over the earlier two kingdom systems.

Five Kingdom Classification

Select the correct option:

🔒 Solution Hidden from View

More diversity in living world Practice Questions

Which feature most strongly differentiates Fungi from Plantae in Whittaker's five kingdom classifica...

If the estimated number of described species on Earth is about 1.7 million and animals constitute ro...

Coelenterates such as Hydra capture prey and defend themselves using specialised stinging cells; wha...

Arthropoda is considered the largest phylum in the animal kingdom; which combination of features chi...

Sponges of the phylum Porifera maintain a continuous water current through their body by means of a ...

Three fundamental characters are shared by every chordate at some stage of life; which set correctly...

Roundworms belonging to phylum Aschelminthes represent an evolutionary advance over flatworms primar...

Rapid proliferation of certain photosynthetic dinoflagellates in coastal waters can turn the sea red...

A fungus reproducing sexually through ascospores borne inside sac-like asci, exemplified by Penicill...

Bryophytes are frequently described as the amphibians of the plant kingdom mainly because of which d...

Gymnosperms are distinguished from angiosperms by a feature of their reproductive biology in which t...

Members of the brown algae owe their characteristic colouration to the dominance of a specific acces...

About This Question

Solution