4.1 Five Kingdom Classification

Introduction

  • Proposed by R.H. Whittaker in 1969.
  • Classifies living organisms into five kingdoms: Monera, Protista, Fungi, Plantae, Animalia.
  • Criteria: Cell structure, body organization, mode of nutrition, phylogenetic relationships.

1. Kingdom Monera

  • Characteristics: Unicellular, prokaryotic (no true nucleus/membrane-bound organelles), cell wall (peptidoglycan).
  • Nutrition: Diverse (autotrophic - photosynthetic/chemosynthetic; heterotrophic - saprophytic/parasitic).
  • Reproduction: Primarily asexual (binary fission).
  • Examples: Bacteria (Cocci, Bacilli, Spirilla), Cyanobacteria (Blue-Green Algae).

2. Kingdom Protista

  • Characteristics: Unicellular, eukaryotic (true nucleus/membrane-bound organelles).
  • Locomotion: Pseudopodia, cilia, flagella.
  • Nutrition: Various (autotrophic, heterotrophic, mixotrophic).
  • Reproduction: Asexual and sexual.
  • Examples: Amoeba, Paramecium.

3. Kingdom Fungi

  • Characteristics: Eukaryotic, heterotrophic (absorption), cell wall (chitin).
  • Body Structure: Most are multicellular (hyphae forming mycelium), some unicellular (yeast).
  • Nutrition: Saprophytic, parasitic, symbiotic (e.g., lichens).
  • Reproduction: Asexual (spores, budding) and sexual.
  • Examples: Mushrooms, Yeasts.

4. Kingdom Plantae

  • Characteristics: Multicellular, eukaryotic, autotrophic (photosynthesis), cell wall (cellulose).
  • Subdivisions:
    • Thallophyta (Algae): Simple thallus body, aquatic, no true roots/stems/leaves.
    • Bryophyta (Mosses): More differentiated, no vascular system, require water for reproduction ("amphibians").
    • Pteridophyta (Ferns): First terrestrial plants with true roots/stems/leaves and vascular system.
    • Spermatophyta (Seed Plants): Most advanced, reproduce by seeds.
      • Gymnosperms: Naked seeds.
      • Angiosperms: Seeds enclosed in fruit (flowering plants).

5. Kingdom Animalia

  • Characteristics: Multicellular, eukaryotic, heterotrophic (ingestion), no cell walls/chloroplasts, motile.
  • Subdivisions:
    • Non-Chordates: (No notochord) Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata.
    • Chordates: (Possess notochord) Pisces (Fish), Amphibia, Reptilia, Aves (Birds), Mammalia.