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SBI3U
CLASSIFICATION
 Early classification divided living organisms into two groups:
KINGDOMS: Plantae vs. Animalia
 But the microscope revealed more organisms which were neither plants
or animals   new kingdom was needed
KINGDOM: Protista
 More problems arose  Fungi were “plant like” but the did not
photosynthesize  another kingdom was added
KINGDOM: Fungi
And then
KINGDOM: Bacteria
 In 1990’s a new kingdom of specific bacteria in extreme environments
was added 
KINGDOM: Archaea or Archaebacteria
RECALL:
Two Cell Types:
 Prokaryote (bacteria and archaea)
 Eukaryote (protista, fungi, plantae, animalia)
Appearance of First Forms of Life:
 Prokaryotes  3.5 billion years ago
 Eukaryotes  1.5 billion years ago
 Multi-celled  700 million years ago
The CLASSIFICATION of LIVING THINGS
Why do we need a classification system?
 Provides specific details to help identify organisms and represent the
relationships between organisms
Taxonomy – is the science of classifying living things.
Carolus Linnaeus (1701-1778):
 Developed the presently used classification system
 Identification based on simple physical characteristics which organized
different species into groups
ORGANIZATION:
 Hierarchy of groups (taxa – plural or taxon – singular)
o Kingdom  largest / most general taxa
o Species  smallest taxa
Hierarchy: 7 Levels (or Taxa) of Classification
 Kingdom
 Phylum
the smaller the taxon,
 Class
the more similar the organisms within it
 Order
 Family
 Genus
 Species
Binomial Nomenclature:
 Used for naming organisms (known as scientific name)
 Two words: both are in italics or underlined, first starts with capital letter
GENUS – First part of the name.
 refers to a group of organisms that are closely related and have similar
characteristics.
SPECIES – Second part of the name.
 refers to a group of organisms that look alike and that are so similar that
they can interbreed and produce fertile offspring.
e.g. Ursus horribilis – grizzly bear
Ursus americanus – black bear (North American)
Ursus maritimus – polar bear
Ursus arctos – brown bear (Alaskan)
Phascolarctos cinereus – koala bear
Ailluropoda melanoleuca – panda bear