Question

What is the criterion for the classification of organisms belonging to the kingdom Monera or Protista?

Answer 1

Hint: Classification of living organisms is an important step to understand present diversity and past evolutionary history of living beings on earth. The criteria are based on the structure of the cell. In monera, the cells are simpler and lack complex organelles that are present in cells of Protista. Which is basically eukaryotic and prokaryotic.

Complete answer:
In 1959 R.H. Whittaker proposed five kingdom classification systems on the basis of Linnaeus’s two kingdom classification systems. The main criteria for the classification of kingdom Monera and Protista are the presence and absence of defined nucleus and cell bound organelles.
- Kingdom Monera and Protista both belong to single- celled life forms, but they are distinct from each other.
- organisms belonging to the kingdom Monera do not have well defined or true nucleus and cell bound organelles. They are called prokaryotes.
Whereas protists have a well- defined nucleus with a nuclear membrane. They are called eukaryotes.

Note: In the five- kingdom classification system all the organisms are grouped into five kingdoms i.s. Monera, Protista, Fungi, Plantae, and Animalia.
Cell structure, mode, and source of nutrition and body organization are the factors on the basis of which classification has done.
All living organisms are divided into two broad categories on the basis of presence or absence or membrane- bound organelles. This led to the formation of the kingdom Monera into which all prokaryotes are included.
Eukaryotes are then divided into unicellular and multicellular organisms on the basis of cellularity. Unicellular eukaryotes are included in the kingdom Protista while multicellular eukaryotes form Fungi, Plantae, and Animalia
Animals are further separated into kingdom Animalia due to a lack of cell walls.
Fungi and plants both contain cell walls therefore they are further divided as autotrophic and heterotrophic on the basis of mode of nutrition.