(二)物种的形成(speciation) 1 物种的概念 species John Ray 在17世纪提出物种是一个繁殖单元。Carl Linnaeus 18世纪中叶提出的物种概念,将稳定性绝对化。Charles Darwin 19世纪提出的变种概念。Mayr 1982 提出物种是由种群组成的生殖单元,它在自然界中占有一定的生境地位
Introduction Differences of opinion will be the final blow for Avebe transgenic potato so reads the heading of a detailed backgro kground article in the Agrarisch Dagblad of Saturday 4 August 2001. This article describes the demise after ten years, of a project by the Avebe potato group which aimed to achieve large-scale cultivation of a otato