Ever since modern biology came up with its system for dividing the animal kingdom, because species of birds, mammals and other large vertebrate are few, and the distinctions between them are clear, a single species 'absence garners great concern, while one's discovery engenders great excitement. And so people have quickly latched onto the species as a unit for protection efforts.
現代生物學開始將物種進行有系統的分類後，由於鳥類與喃乳動物等大型脊椎動物種類少，分類確實，少掉一種容易引起重視，多記錄到一種難能可貴，因此人們可以很快地以種為單位加以救護。