Back Эвалюцыйна значная адзінка Byelorussian Evolučně významná jednotka Czech Unidad Evolutivamente Significativa Spanish یگان فرگشتی مهم Persian Unidades evolutivamente significativas Portuguese Evrimsel olarak önemli birim Turkish
An evolutionarily significant unit (ESU) is a population of organisms that is considered distinct for purposes of conservation. Delineating ESUs is important when considering conservation action. This term can apply to any species, subspecies, geographic race, or population. Often the term "species" is used rather than ESU, even when an ESU is more technically considered a subspecies or variety rather than a biological species proper. In marine animals the term "stock" is often used as well.