Why are there no Unicorns? This is the question that scientists at the University of Calgary asked as they seeked to study evolutionary trajectories of species in general. Instead of directly studying the horse and the horse's lack of a horn, the scientists studied patterns of inflorescence (or the way flowers are arranged on a plant) in plants and asked why, of the infinitely many ways in which flowers could branch, only three types of branching predominate. The scientists developed a mathematical model based on empirical studies of the garden weed Arabidopsis that showed the three types of branching predominate because they follow naturally when growing tips on plants switch to make flowers. This study thus sugggests that the way genes control development does guide the way in which evolution occurs by providing a limited set of possibilities that species can evolve into. This article is light-hearted, an easy read, and short, so check it out here !
Also, I have reviewed Letter to a Christian Nation here .