Inherited reproductive isolation is the basic criterion of species. 透过遗传上的生殖隔离是种的基本标准。
The present favourite is the evolution of cichlid fish in African lakes, where the question of reproductive isolation is much more complex. 目前最喜欢提到的例子是非洲湖泊中鲷鱼的进化,该例子中生殖隔离问题相当复杂。