Plant species change constantly and adapt to their environment. These microevolutionary changes always occur at population level which stays in an interaction to each other. The driving force of these mircoevolutionary processes: small changes in the genetic background are the natural selection. In one environment, only the individuals of the highest fitness can propagate through generations effectively. This leads to an adaptation-based speciation, the adaptive radiation. In parallel, a hybridisation-based evolution is also accepted in the genus Mammillaria. According to research papers, common ancestors of the genera Ferocactus and Mammillaria has evolved in South(-East) Mexico (Puebla and Oaxaca) during the late Miocene or early Pliocene. From this site, the two genera dispersed into two ways: along the Western and Eastern Sierra Madre, in dry habitats.
