Reference Text:
Modern Biology
Chapter 18 – Section 3
Two Modern Systems of Classification
pgs. 347 - 350
• The Six Kingdom System and The
Domain System are two alternate
schemes for classifying life.
Aristotle classified organisms as
either plants or animals..
Linnaeus took it a step further
and classified organisms into
more specific groups such as
class, order, family, genus and species.
http://science.discovery.com/videos/100-greatest-discoveriesshorts-classification-of-species.html
…some organisms don't quite fit into the plant
or animal kingdom.
As a result, several other kingdoms of
organisms are now used.
Today's scientists look at cell structure, how
the organism moves, gets food, and
reproduces to place it in the correct kingdom.
Two Current Classification Systems
•Six Kingdom System
•Three Domain System
Old Five Kingdom System:
Monera include all prokaryotic
organisms, which are all unicellular
life forms that lack a true nucleus.
Protista, Fungi, Plantae,Animalia
include all eukaryotic organisms,
which are all life forms that do
contain a true nucleus and various
organelles.
The NEW Six Kingdom System:
Archaebacteria & Eubacteria include
all prokaryotic organisms, which are
all unicellular life forms that lack a
true nucleus.
Protista, Fungi, Plantae,Animalia
include all eukaryotic organisms,
which are all life forms that do
contain a true nucleus and various
organelles.
FUNGI
ANIMALIA
PLANTAE
PROTISTS
EUBACTERIA
ARCHAEBACTERIA
Broadest, most inclusive taxons
are the Three Domains
Archaea, Bacteria, and Eukaryota
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Six-Kingdom System
Three-Domain System
The main criteria of grouping here is Eukaryotic vs. Prokaryotic
REMEMBER: These systems are not etched in stone!
They have been revised over the years, and will continue
to be revised when new evidence is discovered.
copyright cmassengale
Domain – Archaea
Kingdom - ARCHAEBACTERIA
• Probably the 1 cells to evolve
• Live in HARSH environments
• Found in:
– Sewage Treatment Plants (Methanogens)
– Thermal or Volcanic Vents (Thermophiles)
– Hot Springs or Geysers that are acid
– Very salty water (Dead Sea; Great Salt
Lake) – Halophiles
• Chemosynthesis: use inorganic compounds to
st
make food.
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Kingdom - ARCHAEBACTERIA
Hot Springs
Acid mine drainage
The Dead Sea
Sulfur Springs
Domain - Bacteria
Kingdom - EUBACTERIA
• Some may cause DISEASE
• Found in ALL HABITATS except harsh
ones
• Important decomposers for environment
• Commercially important in making
cottage cheese, yogurt, buttermilk, etc.
(Acidophilus).
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Kingdom - EUBACTERIA
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Live in the intestines of animals
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Domain Eukarya is Divided into 4
Kingdoms:
Protista (protozoans, algae…)
Fungi (mushrooms, yeasts …)
Plantae (multicellular plants)
Animalia (multicellular animals)
•
•
•
•
copyright cmassengale
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Domain: Eukarya
Kingdom: Protista
•Most are unicellular
•Some are multicellular
•Some are
autotrophic, while
others are
heterotrophic
Aquatic
•
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Domain: Eukarya
Kingdom: Protista
Fungus Like –
made of threadlike
fibers
Animal Like –
move around and
eat other
organisms
Plant Like – contain
chlorophyll for
photosynthesis
copyright cmassengale
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Domain: Eukarya
Kingdom: Fungi
• Multicellular, except
yeast
• Absorptive heterotrophs
•
(digest food outside
their body & then
absorb it)
Cell walls made of chitin
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Domain: Eukarya
Kingdom: Plantae
•Multicellular
•Autotrophic (except
for carnivorous plants)
•Absorb sunlight to
make glucose –
Photosynthesis
Cell walls made of
cellulose
•
http://www.youtube.com/watch?v=ph7Ex8rQ-IA
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Mosses
Liverworts
Angiosperms
Gymnosperms
Ferns
Domain: Eukarya
Kingdom: Animalia
•Multicellular
•Ingestive
heterotrophs
(consume food &
digest it inside their
bodies)
Feed on plants or
animals
•
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Domain
Kingdom
Cell Type
Cell Type
Nutrition
Archaea
Archaebacteria
Prokaryote
Unicellular
Both
autotroph and
heterotroph
Bacteria
Eubacteria
Prokaryote
Unicellular
Both
Eukarya
Protists
Eukaryote
Both
Both
Eukarya
Fungi
Eukaryote
Both
Heterotroph
Eukarya
Plantae
Eukaryote
Multicellular
Autotrophic
(mostly)
Eukarya
Animalia
Eukaryote
Multicellular
Heterotroph
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Methanogens,
Thermophiles,
Acidophilles
Characteristics
Cell
Virus
Growth
yes
No
Homeostasis
Yes
No
Metabolism
Yes
No
Mutation
Yes
Yes; necessary for its survival
Genetic Material
Yes
DNA, RNA
Reproduction
Yes by mitosis
*Yes; but only possible when inside
a host cell
Structure
Cytoplasm, membrane bound
organelles, nucleus
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Biologists have developed a precise method to
help them classify and identify unknown
organisms.
The classification tool called a dichotomous key
•Used to identify
organisms
•Characteristics given in
pairs
•Read both characteristics
and either go to another
set of characteristics OR
identify the organism
1a
1b
2a
2b
3a
3b
4a
4b
Tentacles present – Go to 2
Tentacles absent – Go to 3
Eight Tentacles – Octopus
More than 8 tentacles – 3
Tentacles hang down – go to 4
Tentacles upright–Sea Anemone
Balloon-shaped body–Jellyfish
Body NOT balloon-shaped - 5
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