The document outlines the classification of life, detailing three domains: prokaryotes, eukaryotes, and archaea, and how taxonomy has evolved from Aristotle to modern genetic classification. Key figures like Carl Linnaeus and Charles Darwin contributed to the development of hierarchical systems and the concept of genetic relatedness among organisms. Modern classification increasingly relies on molecular phylogenetics and is updated regularly based on new discoveries.

1. Genetics 1:
Classification of
Life
ppt. by Robin D. Seamon
1
HOOK VIDEO: COSMOS-
“Some Things Molecules do”

2. 3 Domains:
Prokaryote: no nucleus or organelles
Eukaryotes: nucleus 7 membrane-bound organelles
VIDEO: How we think complex cells evolved (5:30)
2

3. NEW There are 3
Domains
K
C
O
F
S
G
P
RANKING
SYSTEM
3

4. 4
CC video: comparative
anatomy (10 min)

5. H I S T O R Y
Aristotle: (Greek philosopher 384-322 CE)
classified animals based on method of
reproduction
5

6. Taxonomy: group or categorize organisms
• Before 1700, there were multiple long names for new
species with no rules in naming process
Carl Linnaeus (Swedish) 1735
grouped organisms by shared physical characteristics
• wrote Systems Naturae
3 Kingdoms: 1. Mineral
2. Vegetable
3. Animal
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7. 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)

8. • 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
8

9. • 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
9

10. • 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
10
CC Video: #35 Archaea, Bacteria, Protists (12 min)

11. 11
Archaea- ancient group of prokaryotic
organisms that are still present today --
Extremphiles- types of archaea that live in very
extreme places
Some 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

12. 12
Hiller Lake, Australia
Halophilic archaea & bacteria live in this salty
lake BACK

13. Under-ocean
hot vent
13
Yellowstone hot vent, Wyoming
thermophilic archaea & bacteria live in this
hot vent BACK

14. 14
Methanogenic archaea
BACK

15. 15
Bacteria- ancient group of prokaryotic
organisms that are still present today

16. 16
Eukaryota- group of organisms whose cells
contain a nucleus and membrane-bound
organelles
ALL THE REST

17. Phylogenetic tree
17

18. H I S T O R Y O F C L A S S I F I C A T I O N
1735
Linnaeus
1866
Haeckel
1925
Chatton
1938
Copeland
1969
Whittaker
1990
Woesse
1998
Cavalier-
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
18

19. 1969 Whittaker: 5 Kingdoms
Protists
Monera
Plants
Animals
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
19

20. 1990 Woese: 3 Domains
Eukaryotes
Plants
Animals
Fungi
Protists
Photosynthesize
Asexual & Sexual
Reproduction
Non-mobile
Absorb
Sexual
Reproduction
Non-mobile
Archaea CBacteria
Monera 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
20

21. Protist
Fungi
Tree of life Web Project
Tolweb.org
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