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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.
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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 • Possibly as many as 10 to 100 million with fewer than 10% discovered (1.7 million)
Taxonomy • 1735 Plant and AnimalKingdoms • 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" • 1959 Kingdom Fungi • 1961 Prokaryote defined as cells in which nucleoplasm is not surrounded by a nuclear membrane • 1968 Kingdom Monera proposed • 1978 Two types of prokaryotic cells found
The Three-Domain System Table 10.1
The Three-Domain System Figure 10.1
Endosymbiotic Theory Cyanophora paradoxa Figures 10.2, 10.3
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
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
“Enterotube II” Figure 10.9 - Overview (1 of 3)