Theories about the changes on the organisms, in the time scale, are know since the 18th century. However, the most famous, as well as the more debated, was the one by Charles Robert Darwin, in his great book On the origin of species. It is interesting to note that while this naturalist was born, in 1809, a book by the French naturalist Jean Baptiste Antoine Pierre de Monet, known as Lamarck, was published, Philosophie zoologique, where another theory of the transformations (...) of the organisms were also proposed. Darwin cited that theory quite enthusiastically, as he himself said in the On the origin; his first scientific work were, in fact, inspired in Lamarck, his theory of inheritance, in another of his books, Variation of animals and plants under domestication, was basically lamarckian, particularly related to the inheritance of acquired characters. And, “from so simple beginning”, as Darwin expressed in the last lines of The origin, the “theory of species transmutations”, as he called at first his theory, was changed in the following years, until achieving the hegemonic theory of the XXth century, called The Evolutionary Synthesis. Is this journey that will be presented here, culminating with a contemporary proposal, in 2010, called The Extended Evolutionary Synthesis which is still being confronted with the former theory. Keywords: Biological evolution. Processes of evolution. Genetics. History and philosophy of biology. (shrink)