Pick two related species, one which exhibits sexual dimorphism and one which does not (e.g., robins and blue jays).
Pick two related species, one which exhibits sexual dimorphism and one which does not (e.g., robins and blue jays).
选两个有亲缘关系的物种,一物种展现出同种异形，另一个则无(例如,知更鸟和冠蓝鸦)。