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Taxonomy: involves the identification,
naming, and classification of species
 Consider the names catfish, crayfish, and
silverfish—the first is a fish, the second is a
small freshwater lobster, and the third is an
insect
 To reduce this confusion in discussing
organisms, one goal of taxonomy is to
assign a universal scientific name to each
known species
 Taxonomists also attempt to organize the
diversity of life by classifying species into
larger groups of related species


The system has two main characteristics:
1.
2.
Binomial nomenclature: a two-part Latin name for each
species
a hierarchy, or ordering, of species into broader and
broader groups :
Species, Genus, Family, Order, Class, Phylum, Kingdom
Panthera
pardus:
binomial for
leopard
Panthera leo:
binomial for
African lion
They belong to
the same
genus, but are
not the same
species
Linnaeus divided all known forms of life
between the plant and animal kingdoms
 Where do prokaryotes fit in such a system?
Can they be considered members of the
plant kingdom? And what about fungi?
 American ecologist Robert H. Whittaker
proposed a five-kingdom system
 Three Domains: A domain is a taxonomic
category above the kingdom level

› recognizes three basic groups: two domains of
prokaryotes—the Bacteria and the Archaea—
and one domain of eukaryotes, the Eukarya
6 Kingdom classification system
3 domains of life