Carolus
Linnaeus
is known as the "father of modern taxonomy."
The
Linnaean system classified nature within a hierarchy, starting
with three kingdoms. Kingdoms were divided into Classes and they,
in turn, into Orders, which were divided into Genera (singular:
genus), which were divided into Species (singular: species). Below
the rank of species he sometimes recognised taxa of a lower (unnamed)
rank (for plants these are now called "varieties").
Carolus
Linnaeus pioneered the grouping of organisms based on scientific
names using Latin. His system of giving an organism a scientific
name of two parts, sometimes more, is called binomial nomenclature,
or "two-word naming". His scheme was based on physical
similarities and differences, referred to as characters. Today,
taxonomic classification is much more complex and takes into account
cellular types and organization, biochemical similarities, and
genetic similarities. Taxonomy is but one aspect of a much larger
field called systematics.
Linnaean
taxonomy classifies living things into a hierarchy, originally
starting with kingdoms. Today, many biologists consider Domains
to be a classification above Kingdoms. Kingdoms are divided into
phyla (singular: phylum)—for animals; the term division,
used for plants, is equivalent to the rank of phylum (and the
current International Code of Botanical Nomenclature allows the
use of either term). Phyla (or divisions) are divided into classes,
and they, in turn, into orders, families, genera (singular: genus),
and species (singular: species). Variety (varietas) and form (forma)
are ranks below the level of subspecies that are unique to plant
classification; "form" has largely fallen out of favor
(although some botanists still cling to this rank), and many botanists
now prefer to use "subspecies" instead of "variety"
although the two are not, strictly speaking, of equivalent rank.
Groups of organisms at any of these ranks are called taxa (singular:
taxon), or phyla, or taxonomic groups.