Download Chapter 9: An Introduction to Taxonomy: The Bacteria

Chapter 9: An Introduction to Taxonomy: The Bacteria
Taxonomy
• The science of classification
• Provides an orderly basis for the naming of organisms
• Places organisms into a category or taxon (plural: taxa)
• Carolus Linnaeus: 18th century Swedish botanist; the Father of Taxonomy
Binomial Nomenclature
• The system used to name all living things
• The first name designates the genus (plural: genera) and its first letter is capitalized
• The second name is the specific epithet, and it is not capitalized
• Together the genus and specific epithet identify the species
The Meaning of the Names of Some Microorganisms
• Escherichia coli: Named after Theodore Escherich in 1888; found in the colon
• Entamoeba histolytica: Ent, intestinal; amoebae, shape/movement; histo, tissue; lytic, lysing or
digesting tissue
• Strain: A subgroup of a species with one or more characteristics that distinguish it from other
members of the same species
Classification of Human, Dog, Wolf and a Bacterium
Using a Taxonomic Key
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Dichotomous Key: A commonly used key to identify organisms.
Has paired statements describing characteristics of organisms.
Figure 9.4
Dichotomous Key for Classifying U.S. Coins
The Five Kingdom Classification
Monera, Protista, Fungi, Plantae, Animalia
Some Typical Monerans
Archaeobacteria - Extremophiles able to exploit the unusual habitat of a “black smoker” vent
Some Typical Protists
Some Typical Fungi
Kingdom Animalia
Proposed Major Evolutionary Lines of Descent
Theory About Three Domains
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The Three Domains
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A new category even higher than kingdom
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Archaea
Bacteria
Eukarya
The Three Domain System of Classification
The Shrub of Life
Lateral Gene Transfer
Bacteria vs. Archaea
• Both have cell walls, however, archaea lack peptidoglycan
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Bacteria have fatty acids present in their membranes; archaea have isoprenes
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Bacteria lack histones ; archaea have histone-like proteins associated with the chromosome
Criteria for Classifying Bacteria
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Criteria for Classifying Bacteria
Table 9.4
Biochemical Tests for ID of Bacteria:
Table 9.5
Sugar fermentation
Starch hydrolysis
IMViC
Categories of Viruses
Stromatolite Mats, Fossil Stromatolite Cross Section
Filamentous Cyanobacteria--Paleolyngbya
Probable Evolutionary Tree Arrived at by Numerical Taxonomy
DNA Sequencer
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