Microbial Taxonomy and Classification

1. Taxonomy and Classification
Course : B.Sc. Biotechnology, Biochemistry
Sem II
Sub: Basic Microbiology
Unit 1.2

2. Taxonomy
• Taxonomy = systematics
• science of biological classification, provides a way to
identify organisms and place them in groups with
similar characteristics
• Consists of 3 parts:
1. Classification
2. Identification
3. Nomenclature
of (micro)organisms

3. • Phylogeny – evolutionary history of organism
• Taxonomy produces a formal system for
naming and classifying species to illustrate
their evolutionary relationship.

4. To understand how the classification system works, let’s
compare finding a species to mailing a letter from overseas.
Classification Hierarchy Letter Hierarchy
Kingdom Animalia Country United States
Phylum/Division* Chordata State Pennsylvania
Class Mammal City/Town DuBois
Order Primate Street Orient Avenue
Family Homoidae House Number 1
Genus Homo Last Name Horse
Species sapiens First Name Charlie
4

5. Phylogenetic tree
• Represents hypothesis based on lines of
evidence (i.e. fossils, homologous form)
• Family tree shows evolutionary relationships
5

6. 6

7. Types of Classification Systems
First classification system developed by
Aristotle.
• Aristotle divided living organisms into:
– Plants;
• Herbs,
• Bushes,
• Trees.
– Animals;
• Land,
• Water,
• Air.
7

8. Types of Classification Systems cont.
• Carlolus Linnaeus proposed the Two Kingdom
Classification in 1758.
• The two kingdoms consisted of:
– Plantae
– Animalia
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9. 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.

10. 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
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11. 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
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12. 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
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1

13. • 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

14. Protista
Paramecium diatom
amoeba euglena
2 3
4
5

15. 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)
15

16. 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
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17. • MAJOR GROUPS OF MONERA:
1. Archaebacteria: Methanogens,
Halophyles, thermoacidophyles
2. Eubacteria: Vibrio, mycobacteria
3. Cyanobacteria: Nostoc, Anabena
1
7
HalobacteriumVibrioAnabenaNostoc
6 7 8 9

18. 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
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19. • 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)
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20. Six Kingdom System
• The six kingdom system consists of:
– Eubacteria
– Archaebacteria
– Protista
– Fungi
– Plantae
– Animalia
• Come up with a mnemonic to remember these
six kingdoms! – This mnemonic does not need
to be in any particular order.
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21. Binomial Nomenclature
• What is it?
– A two name system for writing scientific names
1. Genus name – written first and always capitalized
2. Species name – written second and never capitalized
• Both words are to be italicized if typed, or underlined if hand
written
• Example: Felis concolor or F. concolor
• The species name usually relates to some characteristic of the species or
to the person who found the original. For example, the scientific name for
humans is Homo sapiens. (Genus Homo=man, sapiens=thinking. Literally,
in Latin, thinking man.)
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22. Advantages to Binomial Nomenclature
• Indicates similarities in anatomy, embryology, and
evolutionary ancestry
• Example:
– The system suggests that the North American black bear
(Ursus americanus) and the grizzly bear (Ursus horribilis)
are closely related
– Similar organisms are grouped into the same genus – in
this case, Ursus
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23. References
Books:
1. Biology of microorganisms By M. T. Madigan, J. M. Martinko, D. A.
Stahl and D. P. Clark
Images:
1. https://lh4.ggpht.com/BL8zyuw37iAzWft6GzMuHTWQ7LmX1pGCKxaXjY_wF8R
uMzVbHGnNAsu-XFO-r6w_ozc8hHM=s125
2. http://cfb.unh.edu/phycokey/Choices/Amoebae_Flagellates_Ciliates/Ciliates/P
ARAMECIUM/Paramecium_05_600x395_caudatum.jpg
3. http://www.bodc.ac.uk/projects/uk/mfmb/introduction/images/diatoms.jpg
4. http://www.microscopy-uk.org.uk/mag/imgsep01/amoebaproteus450.jpg
5. https://lh6.ggpht.com/mkGhpDrT154r8rgB0tTM4wfgOG0-
ULTlnUzmbRT7pvKbgVUoTrBC9XuJEqxTdQkEniP1jQ=s170
6. http://www.ohio.edu/plantbio/vislab/algaeimage/jpegs/nost1nitr.JPG
7. http://protist.i.hosei.ac.jp/PDB/images/Prokaryotes/Nostocaceae/Anabaena/A
nabaena9c.jpg
8. https://s3.amazonaws.com/healthtap-public/ht-
staging/user_answer/reference_image/8742/large/Cholera.jpeg?1344948822
9. http://plantphys.info/organismal/lechtml/images/halobacterium.jpg