Nothing in biology makes sense except in the light of evolution. (Dobzhanski, 1973) It was during his voyage aboard the Beagle that Darwin developed his theory of evolution. “On the Origin of Species” (Darwin, 1859) proposed two main principles: evolution actually occurs and natural selection is the mechanism. This work published on November 24, 1859 draws a coherent portrait of life bringing together in an orderly manner an astonishing variety of apparently independent facts. It has led biologists to focus on the diversity of organisms, their origins and relationships, their similarities and differences, their geographic distribution and their adaptation to varied environments. Darwin (1859) reached two main conclusions. • All species on earth are descended from ancestral species and it presents a mechanism explaining evolution called natural selection.• Natural selection results in adaptive evolution (prevalence of hereditary characteristics favoring the survival and reproduction of organisms in different environments).Evolution : historical controversyIn order to fully understand Darwin's vision, it is important to understand the historical context and compare it to previous ideas about Earth and life on Earth. “On the Origin of Species” (Darwin, 1859) revolutionized the ideas of the time: not only did it question scientific ideas but it also questioned the foundations of Western culture. Darwin's vision was opposed to the vision of a world made up of immutable species created in a week by a Creator who would have modeled the entire universe. Philosophers like Plato (428-348 BC) and Aristotle (384-322 BC), who had a major influence on Western culture, are said to have opposed the idea of ​​evolution. Plato cou...... middle of paper ......ptation and the emergence of new species were linked. If two groups of individuals of the same species were separated, finches for example, and placed in different environments, then after many generations, the two groups will have accumulated differences allowing them to differentiate between two distinct species. Galapagos finches are differentiated by the size of their beaks, adapted to the food available on the islands. Darwin had an intuition of the importance of these mechanisms in explaining evolution. In the early 1840s, the main principles of Darwin's theory of evolution were formulated through the mechanism of natural selection; however, he did not publish it. Although evolutionary theory germinated in many places, Darwin rejected the publication of his theory, and it was not until 1859 that he published "On the Origin of Species" (Darwin, 1859).