Five Kingdom Classification

Overview of the Five Kingdoms

In 1969, American ecologist Robert H. Whittaker proposed Five Kingdom Classification system.

It overcame the limitations of earlier two-, three-, and four-kingdom systems by giving proper placement to prokaryotes, fungi, and unicellular eukaryotes.

History of Biological Classification

Timeline of classification systems

Two Kingdom System (Linnaeus, 1735): Plantae & Animalia

Three Kingdom System (Haeckel, 1866): Added Protista

Four Kingdom System (Copeland, 1938): Separated Monera

Five Kingdom System (R.H. Whittaker, 1969): Added Fungi as separate kingdom

Whittaker’s system is the most scientifically accurate and widely taught today.

Criteria Used by Whittaker

Whittaker's classification criteria chart
  • Cell Structure
  • Body Organization
  • Cell Wall
  • Nutrition
  • Phylogenetic Relationships

    • Kingdom Monera

    Bacteria under microscope

    Examples: Bacteria, Cyanobacteria, Archaebacteria

    • Prokaryotic, unicellular
    • Cell wall: Peptidoglycan
    • Autotrophic or heterotrophic
    • Asexual reproduction (binary fission)

    Kingdom Protista

    Amoeba and Paramecium

    Examples: Amoeba, Paramecium, Euglena, Algae

    • Eukaryotic, mostly unicellular
    • Autotrophic or heterotrophic
    • Many have cilia or flagella for movement

    Kingdom Fungi

    Mushrooms and yeast

    Examples: Yeast, Mushrooms, Molds

    • Eukaryotic, mostly multicellular
    • Cell wall: Chitin
    • Heterotrophic by absorption
    • Reproduce via spores

    Kingdom Plantae

    Green plants and trees

    Examples: Mosses, Ferns, Conifers, Flowering plants

    • Eukaryotic, multicellular
    • Cell wall: Cellulose
    • Autotrophic (photosynthesis)
    • Non-motile

    Kingdom Animalia

    Diverse animals

    Examples: Sponges, Worms, Insects, Fish, Mammals

    • Eukaryotic, multicellular
    • No cell wall
    • Heterotrophic by ingestion
    • Most are motile