Module 5 Flashcards
- the science of biological classification
- describing, identifying, classifying, and naming of
organisms
Taxonomy
-grouping organisms into taxa
based on mutual similarity or
evolutionary relatedness
Classification
- characterization of an isolate to determine what
species it is
Identification
- assignment of names to taxonomic groups in
agreement with published rules
Nomenclature
- study of the diversity of life (both past and present) and the relationships among living things
through time - uses taxonomy as a means to understand organisms; means by which the characteristics of a species are defined and communicated among microbiologists
Systematics
- collection of strains that share stable properties in common
and differ significantly from other group of strains - relies upon genetic and phenotypic information; 70% DNA-DNA hybridization and 97% 16S rRNA seq identity
Species (in prokaryotes)
- a group of closely related organisms that breed among
themselves
Species (in eukaryotes)
- population of organisms that descends from a pure culture isolate
or from a species - while different strains may be nearly identical genetically, they
can have very different attributes.
Strain
The most famous early taxonomist
was a Swedish botanist, zoologist,
and physician
Carolus Linnaeus
What book did Carolus Linnaeus publish in which he proposed the Linnaean taxonomy
Systema Naturae
How did Linnaeus classify organisms
two kingdoms;
Kingdom, class, order, family, genus
(plural: genera), and species
1st attempt to depict the
common evolutionary history
of all living cells
HAECKEL TREE by Ernst
Haeckel in 1866
Classification with Three Kingdom Tree
HAECKEL TREE (Plantae, Animalia, Protista)
classification for unicellular organisms
Protista
unicellular organisms whose cells lack nuclei and are ancestral to other forms of life
Monera
Five-Kingdom Tree
WHITTAKER TREE
Proposed adding another Kingdom
(Fungi);
turned into five kingdoms: Monera (prokaryotes), Protista (chiefly protozoa and algae), Fungi (molds, yeasts, and mushrooms), Plantae (plants), and Animalia (animals)
Robert Whittaker
Prokaryota contained just ____. Eukaryota contained the other four kingdoms: ____
Prokaryota contained just the Kingdom Monera. Eukaryota contained the other four kingdoms: Fungi, Protista, Plantae, and Animalia
a key feature in the Whittaker Tree,
although the fungi are not truly unicellular
Unicellular or multicellular organization
proposed a four-kingdom classification, elevating the bacteria and blue-green algae into Kingdom Monera
Herbert Copeland
timeline of Evolving trees of life
Carolus Linnaeus - two kingdoms (Animalia and Plantae)
Ernst Haeckel - four kingdoms (Animalia, Plantae, Protista, Monera)
Robert Whittaker - five kingdoms (Animalia, Plantae, Protista, Monera, Fungi)
proposed six kingdoms of life
Carl Woese
Six Kingdoms of Life
Eubacteria, Archaebacteria,
Protista, Fungi, Plantae,
Animalia
Genetics-based tree of life
Six Kingdoms of Life
Why did archea and bacteria separate?
Archaebacteria (simply known
as Archaea) are significantly
different from other bacteria and
eukaryotes in terms of 16S
rRNA gene sequences.
- Introduced by Carl Woese in
1990 - Divides cellular life forms into
Archaea, Bacteria, and
Eukaryote domains. - Revolutionized the
understanding of microbial
evolution
THREE DOMAINS OF LIFE
How is THREE DOMAINS OF LIFE separated
Differences in ribosomal
RNAs (16S rRNA gene) =
synthesize new proteins
- A two-word naming system for identifying organisms by
genus and species. - Each organism is placed in a genus and given a specific
epithet (specific name/species name)
BINOMIAL NOMENCLATURE
can change if the organism is
assigned to another genus because of new information
Generic Name
stable; the oldest epithet for a
particular organism takes precedence and must be
used
Specific Name
a label put before the name of a bacterium which cannot be grown on an agar plate or in any other bacteriology culture
provisional taxonomic name appended to candidate
taxonomic ranks. (i.e. Candidatus Pelagibacter ubique)
Candidatus
Principles of nomenclature
- Genus name can be changed but specific name cannot
- Names are descriptive.
- Designation of categories is
required for classification of organism. - Each distinct kind of organism is designated as a species
- Characterization and Identification
These books act as standard references for identifying and classifying different
- Bergey’s Manual of Systematic Bacteriology
- Bergey’s Manual of Determinative Bacteriology
Rules for naming bacteria is in
International Code for the Nomenclature of Bacteria (1991)
Questions on nomenclature can be answered in
International Journal of Systematic Bacteriology (IJSB)
official publication of record for taxonomy and classification of Bacteria, Archaea, and microbial eukaryotes
International Journal of Systematic and Evolutionary Microbiology (IJSEM)
Involves the study, not of a single cell, but of a population of identical cells
Characterization and Identification
Prerequisite of Characterization and Identification
pure culture
Reasons for doing characterization
- identification purposes
- comparison with other organisms
- exploit characteristics which may be beneficial
Major characteristics used in taxonomy
Cultural
Morphological
Metabolic
Chemical Composition
Antigenic
Genetic
is affected by the nutrients required for growth and the
physical conditions of an environment that will favor growth
Cultural characteristics
Cultural characteristics based on Nutritional types
Based on Energy source
Based on Carbon source
Based on C and E source
organisms feed Based on E source
Phototrophs
Chemotrophs
organisms feed Based on C source
Autotroph
Heterotroph (organotroph)
energy and carbon source of Photoautotroph
Energy Source - sunlight
Carbon Source - carbon dioxide
energy and carbon source of Photoheterotroph
Energy Source - sunlight
Carbon Source - organic compounds
energy and carbon source of Chemoautotroph
Energy Source - inorganic chemicals
Carbon Source - carbon dioxide
energy and carbon source of Chemoheterotroph
Energy Source - organic chemicals
Carbon Source - organic compounds
Cultural characteristics Based on
physical conditions
temperature requirement
pH requirement
oxygen requirement
organisms that thrive between -5 and 15oC
Psychrophile
organisms that thrive between 20 and 30oC (but grows well at lower temperatures)
Psychrotroph
organisms that thrive between 25 and 45oC
Mesophile
organisms that thrive between 45 and 70oC
Thermophile:
organisms that thrive between 70 and 110oC
Hyperthermophile
types of organisms based on temperature requirement
Psychrophile
Psychrotroph
Mesophile
Thermophile
Hyperthermophile
types of organisms based on pH requirement
Acidophile
Neutrophile
Alkaliphile
organisms that opt pH below 5.5
Acidophile
organisms that opt pH 5-8
Neutrophile
organisms that opt pH above 8.5
Alkaliphile
types of organisms based on Oxygen requirement
obligate aerobe
obligate anaerobe
facultative anaerobe
aerotolerant anaerobe
microaerophile
organisms that are completely
dependent on O2; float in flasks
obligate aerobe
organisms where O2 are toxic to
cells; sinks in flasks
obligate anaerobe
organisms that grows with
or without O2; mostly at the top but trickles down to the bottom
facultative anaerobe
organisms that grows equally
well with or without O2; evenly distributed in the flasks
aerotolerant anaerobe
organisms that requires O2 at low levels; slightly below the surface
microaerophile
Other examples of cultural characteristics
form, elevation, margin, growth pattern in slants
Microscopic characteristics which include size, arrangement, ID of
structures, internal structures, organization, shapes
Morphological characteristics
examples of Structures (Morphological characteristics)
lipid droplets
volutin granules
sulfur granules
gas vacuoles
magnetosomes
biochemical/ physiological characteristics i.e., presence of enzymes, fermentation of sugar
Metabolic characteristics
is a molecule that binds to a specific antibody, often stimulating a response in the immune system as a result.
Antigen
aka immunoglobulin are Y-shaped proteins produced by B cells of immune system in response to exposure to antigens
antibodies
DNA Hybridization is under what major characteristic used in taxonomy
Genetic
process of DNA Hybridization
- Isolate DNA from body fluid sample
- Denature DNA sample and combine with DNA probes. Probes are complementary to the gene of interest and labeled with a molecular beacon
- DNA probes will bind to the gene of interest if it is present in the DNA sample