Specii

In biology, a species is a basic unit of classification that groups together individuals sharing a common lineage and visible traits, and, under natural conditions, capable of interbreeding to produce offspring that are viable and fertile. In practice, species are defined by a combination of genetic similarity, reproductive compatibility, and morphological similarity, though different concepts emphasize different criteria.

Species are given unique scientific names through binomial nomenclature, comprising a genus name followed by a specific epithet (for example, Homo sapiens). The system, developed by Carl Linnaeus, provides a universal language for identifying organisms and allows classifications to be revised as new data, especially DNA evidence, become available. The concept of a species is not fixed; taxonomic ranks and boundaries may shift with new research.

Several species concepts coexist. The biological species concept emphasizes reproductive isolation; the morphological or phenetic concept uses structural similarity; the phylogenetic concept defines species as the smallest diagnosable groups sharing a unique evolutionary history. Cryptic species are different species that appear similar morphologically but are genetically distinct; conversely, hybrids occur where distinct species interbreed.

Speciation, the evolutionary process by which new species arise, can result from geographic separation (allopatric speciation) or from ecological or behavioral divergence in the same area (sympatric speciation). Plants often diversify through polyploidy, a rapid form of speciation.

Understanding species is central to studies of biodiversity, ecology, and conservation. Species counts, distributions, and statuses influence conservation priorities and legal protections.