• Hierarchy of Classification:

Linnaeus proposed a classification system by arranging organismsinto taxonomic groups at different levels according to the characteristics they have.

Groups or Levels from top to bottom

→ The major characteristics considered for classifying all organisms into five major kingdoms.
• Type of cellular organization

(i) Prokaryotic cells: These are primitive and incomplete cells without well defined nucleus.

(ii) Eukaryotic cells: These are advanced and complete cells with well-defined nucleus.

• Body organization

(i) Unicellular organisms: These are organisms made up of single cell with all activities performed the single cell.
(ii) Multicellular organisms: These are organisms made up of large number of cells with differentfunctions performed by different cells.

• Mode of obtaining food

(i) Autotrophs: These are the organisms that make their own food by photosynthesis.
(ii) Heterotrophs: These are the organisms which depend on other organisms for food.

Five Kingdom Classification
R. H. Whittaker taxonomist was the first one to propose five kingdom classification.


(i) Type: Unicellular Prokaryotic
(ii) Mode of nutrition: Autotrophic or heterotrophic
(iii) Body: Lack well-defined nucleus and cell organelles
(iv) Examples: Bacteria, Blue-green algae


(i) Type: Unicellular Eukaryotic
(ii) Mode of nutrition: Autotrophic or Heterotrophic
(iii) Body: Some organisms use pseudopodia or cilia or flagella for movement
(iv) Examples: Amoeba, Paramecium, Euglena


(i) Type: Multicellular Non-green Eukaryotic
(ii) Mode of nutrition: Saprophytic or Parasitic Sometimes symbiotic
(iii) Body: Fungus is made up of long filaments called hyphae. The network of hyphae is mycelium.
(iv) Examples: Yeast, Rhiozpus, Mushrooms moulds


(i) Type: Multicellular Eukaryotic
(ii) Mode of nutrition: Autotrophic
(iii) Body: Exhibits high level of tissue differentiation and have specialized body organs.
(iv) Examples: Trees, Plants, Shrubs


(i) Type: Multicellular Eukaryotic
(ii) Mode of nutrition: Heterotrophic
(iii) Body: Exhibits high level of tissue differentiation and have specialized body organs. They havewell developed nervous system.
(iv) Examples: Fish, Insects, Animals, Humans, Birds

Kingdom I: Monera

(i) Prokaryotic, unicellular.
(ii) Can be autotrophs or heterotrophs.
(iii) May or may not have cell wall.
(iv) Examples: Anabaena and Bacteria (heterotrophic), Cyano-bacteria or Blue-green algae(autotrophic).

Kingdom II: Protista

(i) Eukaryotic, unicellular.
(ii) Can be autotrophic or heterotrophic.
(iii) May have cilia, flagella or pseudophodia for locomotion.
(iv) Examples: Plants like unicellular algae, diatoms; animals like protozoans (Amoeba, Paramecium,Euglena); fungi like slime molds and water molds.

Kingdom III: Fungi

(i) Eukaryotic.
(ii) Mostly multicellular but sometimes unicellular (yeast).
(iii) Source of food:
• Mostly saprophytes:
These organisms use decaying material for food.
• Some parasitic:
These organisms live inside body of other living organism to have food and canbe disease causing.

• Symbiotic relation:

These are relations between two organisms in which they live together forbenefit of one or both.
→ Lichens are a symbiotic relation between fungi and cyanobacteria.
→ Here fungi gets food from cyanobacteria and in return cyanobacteria gets water and protectiofrom sunlight through fungi.
(iv) Cell wall is made of chitin.
(v) Examples: Mushrooms (Agaricus), green mold (Penicillium), smut (Aspergilus).

Kingdom IV: Plantae

(i) Eukaryotic, multicellular.
(ii) Autotrophs.
(iii) Cell wall present.