B.Sc. Microbiology II Bacteriology Unit I Classification of Microorganisms

Classification of Microorganisms

1. Classification of Microorganisms Course: B.Sc. Microbiology Sem II Sub : Bacteriology Unit I

2. Types of Classification Systems cont. Carlolus Linnaeus proposed the Two Kingdom Classification in 1758. The two kingdoms consisted of: Plantae Animalia

3. THREE KINGDOM SYSTEM ERNEST HAECKEL‐1866 KINGDOM PROTISTA: It includes unicellular & colonial eukaryotes such as bacteria , algae, fungi & protozoans. KINGDOM PLANTAE: It includes multicellular photosynthetic plants. KINGDOM ANIMALIA: It includes multicellular animals.

4. Types of Classification Systems cont. The next classification system that came about consisted of 5 kingdoms. It was proposed by Robert Whittaker in 1969. The 5 kingdoms consisted of: Plantae Animalia Fungi Protista Monera

5. Robert Whittaker’s Five Kingdom System Plantae Plants are immobile, multicellular eukaryotes that produce their food by photosynthesis and have cells encased in cellulose cell walls. Examples: Ferns, pine trees, roses Animailia Animals are multicellular, heterotrophic eukaryotes that are capable of mobility at some stage during their lives, and that have cells lacking cell walls. Examples: Humans, worms, spiders

6. Robert Whittaker’s Five Kingdom System Fungi Fungi are a eukaryotic, heterotrophic, usually multicellular group having multinucleated cells enclosed in cells with cell walls. They obtain their energy by decomposing dead and dying organisms and absorbing their nutrients from those organisms . Examples: Mushrooms, moulds, yeast 1

7. Protista The most ancient eukaryotic kingdom, protista include a variety of eukaryotic forms. Perhaps they are best defined as eukaryotes that are not fungi, animals, or plants . Cell wall is usually absent, if present it is impregnated with silica (diatoms ). Photosynthetic or non photosynthetic. Locomotory structure may be cilia, flagella , pseudopodia or absent. Examples : Paramecium, amoeba, diatom , euglena, some algae (unicellular), slime moulds Robert Whittaker’s Five Kingdom System

8. Protista Paramecium diatom amoeba euglena 2 3 4 5

9. Robert Whittaker’s Five Kingdom System Monera Monera are the only kingdom composed of prokaryotic organisms, they have a cell wall, and lack both membrane-bound organelles and multicellular forms. Examples: Bacteria, blue-green bacteria (cyanobacteria)

10. Characteristics of Monera : Unicellular or filamentous prokaryotes Omni present (air, soil, hot springs, deserts, deep sea , snow & as parasites) Cell wall is composed of polysaccharides & amino acids( peptido glycons ormurein ) Autotrophic (photo & chemosynthetic) & heterotrophic (saprophytic & parasitic) Reproduce by vegetative, asexual & sexual methods

11. MAJOR GROUPS OF MONERA: Archaebacteria : Methanogens, Halophyles , thermoacidophyles Eubacteria : Vibrio, mycobacteria Cyanobacteria : Nostoc , Anabena 11 Halobacterium Vibrio Anabena Nostoc 6 7 8 9

12. Types of Classification Systems cont .. In the 1970’s, microbiologist Carl Woese , among other researchers conducted studies and concluded that a group of prokaryotic microorganisms called archaebacteria are separate from other monerans . Therefore, they decided to split kingdom monera into two separate kingdoms: Eubacteria Archaebacteria

13. Archaebacteria Unicellular Prokaryotic Exist in extreme environments – they do not need oxygen or light to live Examples: methanogens, extreme thermophiles, extreme halophiles Eubacteria Unicellular Prokaryotic Heterotrophic, autotrophic, and chemotrophic Examples: Bacteria, cyanobacteria (blue-green bacteria)

14. Three Domain System The Three Domain System, developed by Carl Woese , is a system for classifying biological organisms. Over the years, scientists have developed several systems for the classification of organisms. From the late 1960's, organisms had been classified according to a Five Kingdom system. This classification system model was based on principles developed by Swedish scientist Carolus Linnaeus, whose hierarchical system groups organisms based on common physical characteristics .

15. The Three Domain System As scientists learn more about organisms, classification systems change. Genetic sequencing has given researchers a whole new way of analyzing relationships between organisms. The current system, the Three Domain System, groups organisms primarily based on differences in ribosomal RNA structure. Ribosomal RNA is a molecular building block for ribosomes. Under this system, organisms are classified into three domains and six kingdoms. The domains are Archaea, Bacteria, and Eukarya. The kingdoms are Archaebacteria (ancient bacteria), Eubacteria (true bacteria), Protista, Fungi, Plantae, and Animalia. The Archaea and Bacteria domains contain prokaryotic organisms. These are organisms that do not have a membrane bound nucleus. Eubacteria are classified under the Bacteria domain and archaebacteria are classified as Archaeans . The Eukarya domain includes eukaryotes, or organisms that have a membrane bound nucleus. This domain is further subdivided into the kingdoms Protista, Fungi, Plantae, and Animalia.

16. Comparison of Classification Systems Five Kingdom System Kingdoms: Monera , Protista, Fungi, Plantae, and Animalia. Three Domain System Archaea Domain Archaebacteria Kingdom Bacteria Domain Eubacteria Kingdom Eukarya Domain Protista Kingdom Fungi Kingdom Plantae Kingdom Animalia Kingdom

17. References Books: Biology of microorganisms By M. T. Madigan, J. M. Martinko , D. A. Stahl and D. P. Clark Images: https://lh4.ggpht.com/BL8zyuw37iAzWft6GzMuHTWQ7LmX1pGCKxaXjY_wF8RuMzVbHGnNAsu-XFO-r6w_ozc8hHM=s125 http://cfb.unh.edu/phycokey/Choices/Amoebae_Flagellates_Ciliates/Ciliates/PARAMECIUM/Paramecium_05_600x395_caudatum.jpg http://www.bodc.ac.uk/projects/uk/mfmb/introduction/images/diatoms.jpg http://www.microscopy-uk.org.uk/mag/imgsep01/amoebaproteus450.jpg https://lh6.ggpht.com/mkGhpDrT154r8rgB0tTM4wfgOG0-ULTlnUzmbRT7pvKbgVUoTrBC9XuJEqxTdQkEniP1jQ=s170 http://www.ohio.edu/plantbio/vislab/algaeimage/jpegs/nost1nitr.JPG http://protist.i.hosei.ac.jp/PDB/images/Prokaryotes/Nostocaceae/Anabaena/Anabaena9c.jpg https://s3.amazonaws.com/healthtap-public/ht-staging/user_answer/reference_image/8742/large/Cholera.jpeg?1344948822 http://plantphys.info/organismal/lechtml/images/halobacterium.jpg