Inherited reproductive isolation is the basic criterion of species. 透過遺傳上的生殖隔離是種的基本標準。
The present favourite is the evolution of cichlid fish in African lakes, where the question of reproductive isolation is much more complex. 目前最喜歡提到的例子是非洲湖泊中鯛魚的進化,該例子中生殖隔離問題相當複雜。