«Nothing in biology makes sense except in light of evolution.» The famous biologist Theodosius Dobzhansky said it more than forty years ago, and the scientific community still holds it true to this day. In this section, we show why evolution is a fundamental concept that ties together our different sources of knowledge about living beings. We will take a journey to the nineteenth century and learn more about the life and work of Charles Darwin, the English naturalist that proposed the first modern theory of evolution.


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1 | The Christian worldview   Christianity dominated the Western part of the world for centuries, and Westerners relied on the Biblical texts as a source of knowledge. Most naturalists were creationists, i.e. they believed that God had created all living beings, and nature was seen as a static and harmonious whole.

2 | The influence of natural theology in Britain   In Britain, creationism was so embedded in religious doctrine that formed a part of it, the natural theology, and many naturalists were also clergymen. The study of nature was a respectable and pious activity for well-educated British citizens.

3 | From Cambridge to South America   Charles Darwin was born into a wealthy English family in 1809. He first studied to become a doctor, and then switched to theology at the prestigious Cambridge University in order to become a member of the clergy. In 1831, an unexpected invitation to embark on a trip to South America changed all of his plans.

4 | Darwin as a geologist   During his voyage, Darwin came across with various geological phenomena that convinced him of the new geological ideas proposed by Charles Lyell.

5 | The puzzling findings of Darwin’s explorations   Darwin collected numerous fossils and living species during his explorations. Since he lacked the expertise to correctly classify them, he searched for the help of some specialists. The puzzling identity of the specimens led Darwin to doubt creationist interpretations and to see the evolution of species as a more plausible interpretation.

6 | In search of a mechanism   Darwin knew his conjectures on the transformation of species would only be consistently framed if he presented a logical mechanism to account for them. He found one after reading Thomas Malthus’s An Essay on the Principle of Population.

7 | Troubles ahead   Only in 1842 did Darwin try to put his thoughts on evolution to paper. In 1844, he had developed them in an essay. But in that year, the publication of a very controversial book that advocated a similar evolutionary theory led him to delay the publication of his theory.

8 | The long delay   Darwin recognized that he had to gain more expertise as a naturalist if he wanted to be taken seriously by the scientific community, and he devoted himself to the study of a group of marine animals. What had begun as complementary research grew in importance, taking him much more time than he had anticipated. When he finally put an end to his researches in 1854, his evolutionary ideas had changed in significant ways.

9 | One last unexpected surprise   By 1856, pressed by his inner circle of scientific friends, Darwin finally decided to write a book on his theory of evolution. But after two years of ongoing work, he changed his initial plans when he discovered that Alfred Russel Wallace, a fellow naturalist, had come up with a very similar theory. Helped by his friends, Darwin left the big book he had been writing and wrote instead a smaller account to publish as quickly as possible and ensure his priority.

10 | The reception of Darwin’s theory of evolution   In 1859, Darwin finally published his theory of evolution. Not every reaction was bad, but there were quite negative ones from creationists, as expected. The theory polarized opinions since the beginning, and it was impossible to remain indifferent to it.

11 | Darwin's legacy   The British scientific community accepted the existence of evolution by the 1870s, but not Darwin’s theory in its entirety. Like every theory, Darwin’s left some phenomena unexplained, and new questions drove research in new directions.

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