1. Taxonomy – Classifying Organisms

3. The Five-Kingdom System
a.k.a. - prokaryotes

5. Levels of Classification

6. Binomial Nomenclature
2 Part Latin names for living things
‘Scientific Names’
Genus + Species
Ex/ Homo sapiens
We generally use a dichotomous key to name organisms
Carolus Linnaeus ( )

7. Binomial Nomenclature (cont’d)
Back then the Earth was flat, and living things did not evolve…
Now we use PHYLOGENY in combination with old knowledge to study evolutionary history

9. 3 Domains – Based on Evolution
Common Ancestor - ~3.7 Billion Years Ago

11. Classification of Bacteria
                              

12. Classification of Bacteria
Light microscope was the original tool
Initial classification was based on of the shape of the bacterial cells
Cocci
Bacilli
Spirilla
Spirochetes

13. Taxonomy / Systematics
Identification
Distinguishing features
Engine size
Mileage
Number of passengers
Type of transmission
Classification
Organization into groups
Car
Truck
SUV
Van
Nomenclature
Providing a formal name
Genus & species
Ford Crown Victoria
Chevy Impala
Toyota Camry
Honda Civic
Consistent rules for all Scientists
Relevant
Meaningful
Make biological sense
Evolutionary context

14. Domains can be Divided into Many Sub-classifications
Domain: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Escherichia
Species: Escherichia coli

15. Binomial nomenclature
Genus & species
Escherichia coli
Genus name is always capitalized
Species name is never capitalized coli
Both names are always either italicized or underlined
Abbreviation: E. coli

16. Old School Medical Microbiologists said…
One bacterium = One disease
So to these scientists, bacteria were also classified as to the disease they caused
But there are several types of E. coli…
So the naming system for bacteria evolved

17. Extra Stuff for Naming Bacteria
strain or variety – a culture derived from a single parent that differs in structure or metabolism from other cultures of that species
type – a subspecies that can show differences in antigenic makeup ,susceptibility to bacterial viruses, and in pathogenicity
Four Groups Based on Cell Wall Composition
Gram-positive cells
Gram-negative cells
Bacteria without cell walls
Bacteria with chemically unique cell walls