Genetics 1: Classification of
Lifeppt. by Robin D. Seamon
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HOOK VIDEO: COSMOS-“Some Things Molecules do”
3 Domains:
Prokaryote: no nucleus or organellesEukaryotes: nucleus 7 membrane-bound organellesVIDEO: How we think complex cells evolved (5:30)
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H I S T O R Y
Aristotle: (Greek philosopher 384-322 CE) classified animals based on method of reproduction
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Taxonomy: group or categorize organisms
• Before 1700, there were multiple long names for new species with no rules in naming process
Carl Linnaeus (Swedish) 1735grouped organisms by shared physical characteristics
• wrote Systems Naturae
3 Kingdoms: 1. Mineral
2. Vegetable
3. Animal
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Today naming is regulated by Nomenclature Codes allowing names to be divided into ranks:
Binomial nomenclature (genus & species) 1740’s
R A N K I N G S Y S T E M
7CC Video: #19 Taxonomy(12 min)
• 1859 Darwin insisted classification should reflect genetic relatedness
• 1900 Emil Willi Henning: grouped organisms by inferred evolutionary relatedness
• Homologous structures; inherited from common ancestors, so were related
Phylogenetic taxonomy
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• Cladistic system: 1960’s scientists started using DNA sequences to determine common ancestry IGNORING RANKS
• This new field is making changes & revisions in classification everyday.
• International Code of Phylogenetic Nomenclature (PhyloCode) is currently under development
Molecular Phylogenetics
C L A D E S Y S T E M
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• 1990’s: New Grouping based on new discoveries in bacteria metabolism
1. Archaea
2. Bacteria
3. Eukaryota
D O M A I N S
Separated these 2
Includes Protists
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CC Video: #35 Archaea, Bacteria, Protists (12 min)
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Archaea- ancient group of prokaryotic organisms that are still present today --Extremphiles- types of archaea that live in very extreme placesSome examples:
• Halophile: live in extreme salty conditions
• Thermophile: live in extremely hot conditions
• Methanogen: metabolize such that they use acidic conditions (sulfur) and release methane
Under-ocean hot vent
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Yellowstone hot vent, Wyoming
thermophilic archaea & bacteria live in this hot vent BACK
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Eukaryota- group of organisms whose cells contain a nucleus and membrane-bound organelles
ALL THE REST
H I S T O R Y O F C L A S S I F I C A T I O N
1735Linnaeus
1866Haeckel
1925Chatton
1938Copeland
1969Whittaker
1990Woesse
1998Cavalier-
Smith
2 Kingdoms 3 Kingdoms 2 Empires 4 Kingdoms 5 Kingdoms 3 Domains 6 Kingdoms
Mineral Prokaryote Monera Monera Bacteria Bacteria
Protist Protist Protist Archaea Protist
Eukaryote Eukaryote Chromista
Vegetable Plant Plant Plant Plant
Fungi Fungi
Animal Animal Animal Animal Animal
To apply Darwin to
Microscopic organisms
To show having
nucleus or not
To show evolutionary
history of life
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1969 Whittaker: 5 Kingdoms
Protists
Monera
PlantsAnimals
Fungi
Prokaryotes: Eubacteria &
Archeobacteria
Eukaryotes
Absorb & photosynthesize
Asexual Reproduction
Absorb & photosynthesize
Asexual & Sexual Reproduction
Photosynthesize
Asexual & Sexual Reproduction
Non-mobile
Ingest
Asexual & Sexual Reproduction
mobile
Absorb
Sexual Reproduction
Non-mobile
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1990 Woese: 3 Domains
Eukaryotes
PlantsAnimals
Fungi
Protists
Photosynthesize
Asexual & Sexual Reproduction
Non-mobile
Absorb
Sexual Reproduction
Non-mobile
Archaea CBacteriaMonera Monera
Absorb & photosynethsize
Aerobic respiration
Asexual & Sexual Reproduction
Various metabolism: photosynthesis, fermentation,
Methanogenesis respiration
Asexual & Sexual Reproduction
Various metabolism: photosynthesis, fermentation,
Anaerobic & aerobic respiration
Asexual & Sexual Reproduction
Ingest
Asexual & Sexual Reproduction
mobile
NO NUCLEUS
NO NUCLEUS
NUCLEUS
DOMAIN DOMAIN DOMAIN
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