Evolution by Computer by J. L. Crosby , Ph.D. Department of Botany,
Durham Colleges
Primroses usually exhibit two forms (pins and thrums), but on rare occasions genetic change has produced a third (the homostyle): this form is preferred by natural selection and so tends to spread through any population in which it appears. Dr. Crosby has discovered such populations in Somerset. He has used an electronic computer to simulate this evolutionary process, especially the way in which homostyly spreads from population to population.