In taxonomy, binomial nomenclature, also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name, a binomen, binominal name, or a scientific name; more informally it is also historically called a Latin name. In the ICZN, the system is also called binominal nomenclature, "binomi'N'al" with an "N" before the "al", which is not a typographic error, meaning "two-name naming system".
Orcinus orca, the orca or the killer whale
Trichocereus macrogonus var. pachanoi, the San Pedro cactus
Carl Linnaeus (1707–1778), a Swedish botanist, invented the modern system of binomial nomenclature
The bacterium Escherichia coli, commonly shortened to E. coli
A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour, or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet. For example, Boa constrictor is one of the species of the genus Boa, with constrictor being the species' epithet.
All adult Eurasian blue tits share the same coloration, unmistakably identifying the morphospecies.
Ernst Mayr proposed the widely used Biological Species Concept of reproductive isolation in 1942.
Palaeontologists are limited to morphological evidence when deciding whether fossil life-forms like these Inoceramus bivalves formed a separate species.
Blackberries belong to any of hundreds of microspecies of the Rubus fruticosus species aggregate.