Almost everybody living today has been taught in school that life has arisen through a process of evolution and that this process was first proposed by Darwin in 1859, in a book in which he also gave an explanation of the mechanism through which this has occurred, namely natural selection. Such selection is supposed to ensure the differential survival of living beings such that among the members of a particular terminal taxon, those possessing some individual variations which are useful in "the struggle for existence", thus having a specific adaptation to the environment, will have a greater chance to survive and procreate than their congeners. If the trait is inheritable, it will be passed on to the offspring and spread to other members of the taxon, and through the gradual accumulation of such slight variations large changes may finally be accomplished, so large indeed that the taxon will transform into a new species.