So, as you all know, species lived in particular ecological niches and particular environments, and the pressures of those environments selected which changes, through random mutation in species, were going to be preserved.
ご存じの通り 特定の生態的ニッチや 特定の環境 またその環境下のプレッシャーが 種のランダムな変異を促し またどういった変異が 保たれていくかを選択します