The idea that species are not fixed, but change over time, has deep roots in the history of human thought. Greek philosophers such as Anaximander and Empedocles already speculated about the possibility of organisms transforming from simpler forms. However, these ideas were not based on empirical evidence and were overshadowed by the literal interpretation of sacred texts during the Middle Ages.
During the 18th century, a growing body of evidence from naturalistic exploration began to challenge the idea of the immutability of species. Naturalists such as Carl Linnaeus, although a defender of the fixed classification of organisms, recognized the existence of variations within species. Buffon, for his part, proposed that species could degenerate and adapt to different environments, and Erasmus Darwin, Charles’ grandfather, suggested the possibility of a common ancestor for all living beings.
Advances in geology and paleontology during the 18th and 19th centuries provided new clues about the history of Earth and life on it. Geologists such as James Hutton and Charles Lyell proposed that the Earth was much older than previously thought and that geological processes had acted gradually over millions of years. Paleontology, for its part, revealed the existence of fossils of extinct organisms, suggesting that life on Earth had changed over time.
The letter that changed everything
The history of science, like life itself, is full of unexpected turns, rivalries and collaborations. The case of Darwin and Wallace is a fascinating example of how the passion to discover the mysteries of nature can lead to great discoveries, but also to moments of tension.
Let’s imagine two naturalists, each one in a corner of the world, obsessed with answering the same question: How did all the species of living beings that inhabit our planet arise? One, Charles Darwin (1809-1882), sailed aboard the Beagle, exploring the Galapagos and collecting thousands of specimens. The other, Alfred Russel Wallace (1823-1913), delves into the lush Amazon jungle, looking for clues about the distribution of living beings.
Both, without knowing each other, were about to revolutionize our understanding of the natural world. Independently, they had reached the same conclusion: species are not immutable, but evolve over time through a process that Darwin called “natural selection.”
In 1858, Wallace, from distant Indonesia, sent a letter to Darwin. In it he presented his theory of evolution by natural selection, a theory almost identical to the one Darwin had been developing for years. The English scientist was stunned. His life’s work seemed about to be eclipsed.
Darwin was in a dilemma. On the one hand, he was overwhelmed by the coincidence with Wallace. On the other hand, he had been working on his theory for years and had an immense amount of data to support his ideas. With the help of his colleagues, he decided to present a summary of his work along with Wallace’s letter at a meeting of the Linnean Society in London.
The joint presentation
The joint presentation of the ideas of both scientists was a crucial moment in the history of science. And both naturalists, without searching for it, had reached the same conclusion through independent paths. The theory of evolution by natural selection was born.
Despite the coincidence in their ideas, the relationship between Darwin and Wallace was not free of tensions. Some historians have suggested that there was some rivalry between the two, especially in the early years. However, over time, the relationship between the two became more cordial and collaborative: Darwin always recognized the importance of Wallace’s work and defended it publicly.
But why did Darwin become more famous?
Although both scientists presented their ideas simultaneously, Darwin became the face of the theory of evolution. Because? There are several reasons: Darwin published a monumental book (‘The Origin of Species’) in which he developed his theory exhaustively, providing a large amount of evidence and arguments; Darwin was a meticulous and patient scientist, while Wallace was more impulsive and adventurous; and finally, the former lived in the epicenter of the scientific community in London, while Wallace was far away in Southeast Asia.
The story of Darwin and Wallace is a reminder that science is a human enterprise, full of passions, rivalries and collaborations, where the search for truth can unite people from different backgrounds and cultures.
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