Espèce

Espèce is the basic unit of biological classification in French, corresponding to the English term species. It denotes a group of organisms that share a distinct gene pool and, in most cases, can interbreed to produce fertile offspring under natural conditions. However, there are exceptions and multiple species concepts in use.

The Biological Species Concept defines species by reproductive isolation from other groups, but it does not apply to asexual organisms, extinct lineages known only from fossils, or many plants with extensive hybridization. Other concepts focus on morphological similarity (morphological species concept), genetic lineage (phylogenetic species concept), or ecological roles (ecological species concept).

In taxonomy, species are named with binomial nomenclature: genus name plus a specific epithet, forming a two-part name such as Homo sapiens. The name anchors the species concept and is associated with a type specimen that serves as the reference for the name.

Delimitation of species combines evidence from morphology, genetics, behavior, and ecology. It can be dynamic, with revisions as new data become available. Speciation is the process by which new species arise, often through geographic isolation or ecological differentiation that reduces or prevents gene flow between populations.

Etymology: the word species derives from Latin species, meaning appearance or kind. In many languages, including French, the term denotes a taxonomic rank used to classify the diversity of life.