Biological classification:KINGDOM MONERA: Archaebacteria and Actinomycetes

Classification by Aristotle:


  • Aristotle was the earliest to attempt a scientific basis for classification.
  • He classified plants and animals as two groups
  • He classify plants into trees, shurbs and herbs. He divided animals in two groups , those who have red blood  and those do not contain red blood.


Classification by Linnaeus:

  • Linnaeus classified as Two Kingdoms, i.e Plantae and Animalia.

  • But this two kingdom classification found inadequate because a large number of organism did not fall in either category. There was no differentiation between unicellular and multi cellular, autotrophic and heterotrophic, difference in their cell wall composition, so a need was felt to classify them in an appropriate manner. So Whittaker classified it again and it is widely used now a days.


Whittakers classification:


  • R.H.Whittaker proposed a Five kingdom classification in the year 1969. They are

  1. Monera
  2. Protista
  3. Fungi
  4. Plantae
  5. Animalia

  • The main criteria for classification was  Cell structure, thallus organisation, mode of nutrition, reproduction and phylogenetic relationships.
  • He reflects on not only reflects on morphological, physiological and reproductive similarities but also focussed on phylogenetic/evolutionary relationships.


Kingdom monera


  • It includes mainly bacteria. It is prokaryotic, cell wall is made up of polysaccharides and amino acid and it is non-cellulosic.
  • Nuclear membrane is absent and it is unicellular.
  • It may be autotrophic (photosynthetic or chemosynthetic) or heterotrophic (saprophytic or parasitic).


1. Archaebacteria


  • It is prokaryotic, heterogenous bacteria lives in extreme conditions like salty (halophile) and hot springs (thermoacido philes) and also lives in marshy areas. This is due to thier cell wall structure which contains branched chain lipids and made of pseudomurien
  • These are present in ruminants like cows and buffaloes and produce methane gas i.e. biogas  from dung.
  • They are usually chemoautotrophs or organotrophs.
  • Reproduction is by binary fission, fragmentation or formation of buds. etc.

2. Actinomycetes:


  • It is aerobic, gram positive bacteria and forms specialized asexual spores.
  • It involves in mineralisation of organic matter and are primary source for antibiotics prepared from genus streptomyces.
  • Cell wall is made of mycolic acid.
  • Usually they are saprophytes and decomposers but some like mycobacterium and corynobacterium are parasitic.
  •  Reproduction is mainly by fragmentation.


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