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Taxonomy. Science of Classification, Nomenclature, Identification Organisms are named and arranged into taxa Provides: universal names reference facilitates research, scholarship and communication. Taxonomy. Systematics or phylogeny
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Taxonomy • Science of Classification, Nomenclature, Identification • Organisms are named and arranged into taxa • Provides: • universal names • reference • facilitates research, scholarship and communication
Taxonomy • Systematics or phylogeny • Provides tools for clarifying evolution of organisms as well as their interrelationships • All Species Inventory (2001-2025)
History of Taxonomy • 1735 Carlous Linnaeus: 2 Kingdoms • 1857 Bacteria & fungi put in the Plant Kingdom • 1866 Ernst Haeckel: 3 Kingdoms • 1937 "Prokaryote" term introduced • 1959 Kingdom Fungi
History of Taxonomy • 1961 Current definition of prokaryote introduced • 1969 Robert Whittaker: 5 kingdoms • Plantae; Animalia; Fungi; Protista; Monera • 1978 Carl Woese: 3 Domains • Eukarya, Bacteria and Archaea • Based on variation in cellular composition • Primary evidence to support comes from differences in rRNA sequences
The Three-Domain System Figure 10.1
Three Domains Table 10.1
Nested Taxonomical Hierarchy Figure 10.5
Species Definition • Eukaryotic species: • Prokaryotic species: • Clone • Strain • Viral species:
Methods of Identifying Microorganisms • Morphological characteristics • Differential and structural stains • Biochemical tests • Serology – based on antigenic nature of microbes • Phage typing –determines to which phages a bacteria is susceptible • Analysis of nucleic acids
Acid fast bacilli and non-acid fast cocci Gram - bacilli and Gram + cocci Endospore stain Flagella stain
Dichotomous key for biochemical tests based on enzyme activity
Rapid Identification Tests Figure 10.9
Microbes are antigenic • Combine known antiserum + unknown bacterium • Slide agglutination • ELISA • Western blot Figure 10.10
Phage Typing Figure 10.13
Analysis of nucleic acids • DNA base composition • DNA fingerprinting • Electrophoresis of RFLPs • Nucleic acid hybridization • rRNA sequencing • PCR