Question

What are the two kingdoms of the two-kingdom system of classification?
A. Plant kingdom and Animal kingdom
B. Monera and Animalia
C. Monera and Protista
D. Animalia and Protista

Answer 1

The two-kingdom classification was proposed by Carolus Linnaeus in 1735. All living organisms were classified into two groups based on their nutrition and locomotion.

Complete answer:
Plant kingdom and animal kingdom – correct answer
The two-kingdoms of living things are Animalia for animals and vegetabilia for plants. All living organisms that could move, had compact body structure and holozoic mode of nutrition were grouped under Kingdom Animalia and the rest under Kingdom Plantae.
However, some limitations were noted in this system of classification:
Evolutionary relationships between the kingdoms were not indicated
It grouped prokaryotic and eukaryotic as well as unicellular and multicellular organisms. But failed to mention viruses and viroids or Lichens and Euglena in either group.
Certain fungi like slime moulds had dual characteristics. Their mode of nutrition was holozoic and developed cell walls in their reproductive stage. Thus these could not be grouped in either.

Monera and Animalia – an incorrect answer
Kingdom Monera is part of the five-kingdom classification proposed by R. H. Whittaker in 1969. Microscopic unicellular prokaryotes are part of this kingdom and include archaebacteria, bacteria, cyanobacteria (BGA), and filamentous actinomycetes.

Monera and Protista – Incorrect answer
Kingdom Protista is also a part of the five-kingdom classification. This includes unicellular and colonial eukaryotes. They are divided into groups based on their mode of nutrition. Both sexual as well as asexual modes of reproduction are seen in the organisms of this kingdom.

Animalia and Protista – Incorrect answer
The combination of kingdoms in this option is wrong as one belongs to the two-kingdom classification system and the other to the five-system classification.

Hence, the correct answer is option (A).

Note: Living organisms have been classified in three different ways:
-Two-kingdom classification
-Five-kingdom classification
-Six-kingdom and three domain classification
Each is known for its merits and demerits. However, the six kingdom classification proposed by Carl Woese in 1990 is the most recent and widely followed system of classification. Although it has its limitations it has replaced the other two systems.