The necessity to breathe in the atmosphere would have made to appear pulmes in the fish that had started to pass small periods are d' water, what it would have allowed its descendants to live in land more time, fortifying the pulmes for the exercise; the gills, each time less used by the pulmonados fish, had finished for disappearing. Thus, the mechanism of formation of a new species would be, in general lines, the following one: some individuals of an ancestral species started to live in a different environment; the new environment created necessities that before did not exist, which the organism satisfied developing new hereditary characteristics; the carriers of these characteristics started to form a new species, different of the first one. The doctrine of Lamarck was published in Philosophie zoologique (1809; Philosophy zoological), and had, as main merit, to excite debates and research in a field that, until then, was exclusive domain of the philosophy and the religion. Posterior studies had demonstrated that, only the first postulate of the lamarckismo, was correct; in fact, the environment provokes in the individual adaptativas modifications; but the thus acquired characters do not transmit the offspring. In 1859, Charles Darwin published The Origin of Species (the origin of the species), book of great impact in the scientific way that put in evidence the paper of the natural election in the mechanism of the evolution.
Darwin broke of the comment which according to, inside from a species, the individuals differs ones of the others. It has, therefore, in the fight for the existence, a competition between individuals of diverse capacities. Most adapted they are the ones that leave bigger number of descendants. The darwinismo was basically correct, but it had of being complemented e, in some aspects, corrected for the evolucionistas of century XX so that if it transformed into the solid evolucionista doctrine of today.