Classification of Microorganisms 10 Classification of Microorganisms

Taxonomy Taxonomy The science of classifying organisms Provides universal names for organisms Provides a reference for identifying organisms

Taxonomy Systematics or phylogeny: The study of the evolutionary history of organisms. All Species Inventory (2001-2025) To identify all species of life on Earth

Taxonomy 1735 Plant and Animal Kingdoms 1857 Bacteria and fungi put in the Plant Kingdom 1866 Kingdom Protista proposed for bacteria, protozoa, algae, and fungi 1937 Prokaryote introduced for cells "without a nucleus" 1961 Prokaryote defined as cells in which nucleoplasm is not surrounded by a nuclear membrane 1959 Kingdom Fungi 1968 Kingdom Prokaryotae proposed 1978 Two types of prokaryotic cells found

The Three-Domain System Table 10.1

The Three-Domain System Figure 10.1

Table 10.2

Endosymbiotic Theory Figures 10.2, 10.3

Source of Specific Epithet Scientific Names Scientific Binomial Source of Genus Name Source of Specific Epithet Klebsiella pneumoniae Honors Edwin Klebs The disease Pfiesteria piscicida Honors Lois Pfiester Disease in fish Salmonella typhimurium Honors Daniel Salmon Stupor (typh-) in mice (muri-) Streptococcus pyogenes Chains of cells (strepto-) Forms pus (pyo-) Penicillium chrysogenum Tuftlike (penicill-) Produces a yellow (chryso-) pigment Trypanosoma cruzi Corkscrew-like (trypano-, borer; soma-, body) Honors Oswaldo Cruz

Taxonomic Hierarchy Figure 10.5

Species Definition Eukaryotic species: A group of closely related organisms that breed among themselves Prokaryotic species: A population of cells with similar characteristics Clone: Population of cells derived from a single cell Strain: Genetically different cells within a clone Viral species: Population of viruses with similar characteristics that occupies a particular ecological niche

Domain Eukarya Animalia: Multicellular; no cell walls; chemoheterotrophic Plantae: Multicellular; cellulose cell walls; usually photoautotrophic Fungi: Chemoheterotrophic; unicellular or multicellular; cell walls of chitin; develop from spores or hyphal fragments Protista: A catchall for eukaryotic organisms that do not fit other kingdoms

Prokaryotes Figure 10.6

References Bergey’s Manual of Determinative Bacteriology Provides identification schemes for identifying bacteria and archaea Morphology, differential staining, biochemical tests Bergey’s Manual of Systematic Bacteriology Provides phylogenetic information on bacteria and archaea Based on rRNA sequencing Approved Lists of Bacterial Names Lists species of known prokaryotes Based on published articles

Identification Methods Morphological characteristics: Useful for identifying eukaryotes Differential staining: Gram staining, acid-fast staining Biochemical tests: Determines presence of bacterial enzymes Figure 10.8

Figure 10.7