A group of organisms that differ from all other groups of organisms and that
are capable of breeding and producing fertile offspring. This is the smallest
unit of classification for plants and animals.
An interbreeding group of organisms that is reproductively isolated from all
other organisms, although there are many partial exceptions to this rule in
particular taxa. Operationally, the term species is a generally agreed
fundamental taxonomic unit, based on morphological or genetic similarity, that
once described and accepted is associated with a unique scientific name.