STM 008 (SAS 22) DISCOVERING AND COMPARING THE 5 AND 6 KINGDOM SYSTEMS

ROBERT WHITTAKER


  • In 1969, Whittaker popularized the Five Kingdom System. 

  • He based the classification on what type of cell is and its mode of nutrition. 

  • It emphasized the structural differences between prokaryotes and eukaryotes. 

    • Prokaryotes are unicellular without true nucleus.

    • Eukaryotes are multicellular and unicellular with a true nucleus.


FIVE KINGDOM SYSTEM


  • Prokaryotic System 

    • Kingdom Monera contained the prokaryotes. 

  • Eukaryotic Systems 

    • Kingdom Protista contained the unicellular eukaryotic organisms (protozoa and unicellular eukaryotic algae). 

    • Kingdom Fungi contained the molds and yeasts which obtain their food by absorptions nutrients from dead decays. 

    • King Plantae included multicellular photosynthetic organisms, higher plants and multicellular algae. 

    • Kingdom Animalia consisted of the invertebrates and vertebrates. Most of these forms ingest their food and digest it internally, although some forms are absorptive to some extent.

CARL WOESE 


  • In 1990, proposed the 6-Kingdom system. 

  • The prokaryotes (Monera) are split into two kingdoms based on ribosomal RNA and other products. 

  • This system includes two prokaryotic kingdoms and four eukaryotic kingdoms.


SIX KINGDOM KINGDOM


  • Prokaryotic Kingdoms

    • Kingdom Archaebacteria contain cell walls that lack muramic acid. This kingdom includes those that live in highly saline environments (halophiles), very hot environments (thermophiles) and in environments with methane gas.

    • Kingdom Eubacteria are the true bacteria. Their cell walls have peptidoglycan. They can be autotrophic or heterotrophic. It includes proteobacteria, gram bacteria, gram negative bacteria, cyanobacteria, spirochetes and chlamydia.

  • Eukaryotic Systems

    • Kingdom Protista who exhibit more structural and functional diversity than any other groups of eukaryotes. They are most nutritionally diverse of all eukaryotes, including photoautotrophs, heterotrophs and mixotrophs. 

    • Kingdom Fungi cell walls that contain chin. These lack chlorophyll and are heterotrophic. Some of these are decomposers and parasites. 

    • Kingdom Plantae are nonmotile photosynthetic autotrophs that contain chloroplasts. They  have cell walls that are made of cellulose. It includes bryophytes (seedless), ferns and allies (gymnosperm) and the seed-bearing plants (angiosperm).

    • Kingdom Animalia requires oxygen for aerobic respiration. They reproduce sexually and asexually. They are motile during at least a part of their life cycle.