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. 'evolution. “On the Origin of Species” (Darwin, 1859) proposed two fundamental principles: evolution really happens and natural selection is its mechanism. This work published on November 24, 1859 paints a coherent portrait of life by neatly bringing together a surprising variety of seemingly independent facts. This 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 various environments. Darwin (1859) came to two main conclusions. • All species on earth descend from ancestral species and has a mechanism that explains evolution called natural selection. • Natural selection leads to adaptive evolution (prevalence of hereditary characteristics that favor the survival and reproduction of organisms in different environments) .Evolution: Historical ControversyTo 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. “The Origin of Species” (Darwin, 1859) revolutionized the ideas of the time: it not only questioned scientific ideas but also questioned the foundations of Western culture. Darwin's vision was opposed to the vision of a world of immutable species created in a week by a Creator who fashioned the entire universe. Philosophers such as Plato (428-348 BC) and Aristotle (384-322 BC), who had a great influence on Western culture, would have opposed the idea of ​​evolution. Plato's cou......middle of paper ......ptation and the emergence of new species were linked. If two groups of individuals of the same species were separated, for example finches, and placed in different environments, after many generations the two groups will accumulate differences that will allow them to differentiate two distinct species. Galapagos finches differ in the size of their beaks, adapted to the food available on the islands. Darwin understood the importance of these mechanisms in explaining evolution. In the early 1840s, the fundamental principles of Darwin's theory of evolution were formulated by the mechanism of natural selection; however, he did not publish it. Although evolutionary theory had sprouted in many places, Darwin refused to publish his theory, and it was only in 1859 that he published “The Origin of Species” (Darwin, 1859).