microbiology lecture by L Mugala 2 2024.pptx

Microbiology lecture

1. TAXONOMIC CLASSIFICATION AND NOMENCLATURE OF ORGANISMS (LECTURE 2) BY L. Mugala ©2024

2. Taxonomic Classification of organisms Taxonomy is the science of classifying organisms based on evolutionary relationships ( i.e the more similar the name, the closer the evolutionary relationship) Taxonomic classification is therefore the placing of organisms into taxa ( groups) based on; Cell type (Prokaryotic or Eukaryotic) Cell number (Unicellular or Multicellular) Reproduction ( Asexual or Sexual) Nutritional requirements (carbon source )- (Autotrophs or heterotrophs)

3. Taxonomic Classification Of Organisms There are 8 taxa/ranks in this scientific classification as shown below Domain is the highest hierarchy or taxon (group) while species is the lowest Members of each taxon are somehow related Members of the lower level taxa ( e. g species) are fewer and more related to each other while members of the upper taxa level ( e.g. Domain) are more and less related

4. Taxonomy of Living Things

5. Taxonomic Classification of organisms DOMAIN Is the highest hierarchy/taxon/group There are 3 domains, namely; Archea Bacteria Eukarya Domains are further divided into five(5) kingdoms distributed as follows based on cell type, cell number, reproduction, nutritional requirements

6. Taxonomic Classification of organisms Domain # 1 : Archaea Kingdom # 1 : Archaebacteria Characteristics Are prokaryotes Are unicellular whose cell walls lack peptidoglycan Reproduce by binary fission Are autotrophs and heterotrophs Live in harsh environmental conditions like hot spring vents

7. Taxonomic Classification of organisms Domain # 2 : Bacteria Kingdom # 2 : Eubacteria (Monera) C haracteristics Are prokaryotes Are unicellular whose cell walls contain peptidoglycan Reproduce by binary fission Are autotrophs and heterotrophs

8. Taxonomic Classification of organisms Domain # 3 : Eukarya Kingdom # 3 : plantae(the plants) Characteristics Are eukaryotes (have true nucleus) Are multicellular with cell walls containing cellulose Reproduce asexually and sexually Are photoautotroph s=use sunlight to obtain carbon from carbon dioxide

9. Taxonomic Classification of organisms Domain # 3 : Eukarya Kingdom # 4 : Animalia (animals) Are eukaryotes Are multicellular without cell walls Reproduce sexually Are heterotrophs = get preformed carbon

10. Taxonomic Classification of organisms Domain # 3 : Eukarya Kingdom # 5 : Protista Characteristics Are prokaryotes Mostly are unicellular with few multicellular Most of them reproduce asexually and few sexually May be autotrophic or heterotrophic in nature

11. Taxonomic Classification of organisms Kingdom # 5 : Protista There are 3groups Plant like protists = Phytoplankton These are autotrophs Have cell walls Animal like protists = Zooplankton These are heterotrophs They move Fungi-like protists = slime molds These are heterotrophs

12. Taxonomic Classification of organisms Domain # 3 : Eukarya Kingdom # 6 : Fungi Characteristics Are eukaryotes Both unicellular and multicellular exist with their cell walls containing chitin and glucans Reproduce asexually and sexually Are heterotrophs

13. Hierarchy of Escherichia coli Domain : Bacteria Kingdom: Eubacteria Phylum: Proteobacteria Order: Enterobacteriales Family: Enterobacteriaceae Genus: Escherichia Species: Escherichia coli

14. Nomenclature of organisms Nomenclature is the scientific way of naming organisms using Binomial system (that is using two words that refer to the genus and the species Names assigned to microorganisms are in Latin The following rules apply when naming the organisms ; 1. The Genus name comes first followed by S pecies name

15. Nomenclature of organisms 2. The first letter of the genus is always capitalized while the species name is always in small letters example: Staphylococcus aureus 3. N ames are underlined if handwritten or italicized if typed Examples: Handwritten : Staphylococcus aureus Typed: Staphylococcus aureus

16. Nomenclature of organisms 4. Only the genus name can be abbreviated followed by a full stop then the name of the species Examples: Handwritten: S . aureus Typed: S. aureus

17. Origins of the names of organisms 1. Named after their discoverers and their habitats E.g. Escherichia coli named after Theodor Escherich 2. Named after their discoverers and the diseases they cause E.g Klebsiella pneumoniae- ---from pneumonia, a disease it causes 3. Named after the place of discovery e.g Ebola virus —discovered along River Ebola in DRC(Congo) 4. Named based on the shape and arrangement e.g Staphylococcus aureus —comes from the Latin word Staphyle which means grapes( organisms appear in clusters) 5. Named after the year of discovery e.g Covid 19 (discovered in 2019) 6.etc