Two approaches to transform evolutionary biology

Radical by nature: The revolutionary life of Alfred Russel Wallace. Costa, J. T. 2023. Princeton University Press, Princeton, NJ. xviii+515 pp. US$39.95 (hardcover). ISBN 978-0-691-23379-6.

Enchanted by Daphne: The life of an evolutionary naturalist. Grant, P. R. 2023. Princeton University Press, Princeton, NJ. xii+ 345 pp. US$35.00 (hardcover). ISBN 978-0-691-24624-6.

Alfred Russell Wallace and Peter Raymond Grant are two biologists who marked evolutionary biology, each in their own distinct way. Wallace is the father of biogeography and, alongside Charles Darwin, the coauthor of the theory of evolution. Grant discovered that evolution can occur over relatively short periods (not just over geological time as Darwin posited); that evolution is unpredictable because selection pressures fluctuate with environmental conditions; and that hybridization can produce new species. While reading these books, I was struck by the many contrasts between the lives of the two figures. Wallace uncovered and understood the mechanisms of evolution in a world where thought was dominated by religious beliefs, whereas Grant looked for evidence of natural selection at a time when most societies had already accepted the theory of evolution.

There are more contrasts. Wallace was raised in a large, poor family in the early 19th century and was a self-taught scientist. A kaleidoscopic naturalist, his interests ranged from geology and astronomy to botany and entomology. His passion for insects (especially beetles) was kindled at age 21, partly through his friendship with Henry Bates, another naturalist who left a lasting legacy in ecology. Except for meeting Bates in his early career, Wallace was essentially working alone, an outsider to the main scientific circles of the time. His correspondence with prominent scientists started only later in his life. Grant grew up more than a century later in a small family affected by his parents’ early divorce. He studied at Cambridge, and throughout his career, he met eminent colleagues, which makes me think he was part of a vibrant scientific community. Grant was mainly interested in birds during his career, a passion he developed when he was 14 years old—although he occasionally studied other vertebrates. This high degree of specialization contrasts sharply with the broader approach of past naturalists, such as Wallace. Although modern scientists are often very specialized, it is worth questioning whether a multidisciplinary approach is more beneficial. My impression, also from reading Costa's book, is that Wallace's broad expertise may have been instrumental in his groundbreaking insights. Contrastingly, Grant's acute observations, such as documenting the hybridization between finch species, may have been the result of a good eye (and ear, given that bird songs played a role) for details and his focus on a single natural laboratory, the Galápagos.

There is, however, an essential aspect uniting Wallace and Grant: their predisposition to travel. In the era of meta-analyses and syntheses of various kind, this should remind us how important first-hand field experience is for ecology. We cannot be solely “desktop ecologists”. Both Wallace and Grant started gaining such experiences at a young age. Grant went on a school expedition to Iceland at 19, moved to Canada for his PhD studies and then to the United States, and conducted research in Mexico, the Balkans, the Middle East, and, extensively, in the Galápagos. All these experiences seem to have been quite adventurous but, luckily, never too dangerous. For Wallace, it was a different story. He traveled to the Amazon with his friend Bates when they were 25 and 23 years old, respectively. The two young naturalists collected numerous specimens and made important observations that proved useful to the theory of evolution. Bates also discovered the famous mimicry form in butterflies that today bears his name. Yet, they parted ways relatively soon for unclear reasons. Eventually, Bates spent nearly 11 years in South America. Wallace's trip to the Amazon lasted slightly more than 4 years and ended with the loss of most of his collection in a shipwreck, the death of his younger brother Edward due to yellow fever, and him barely surviving malaria. It may have been a complete tragedy if not for the many zoological, botanical, and anthropological observations and his agent Samuel Stevens. Although most of his work was lost (except for a sheaf of palm and fish illustrations), Wallace returned to London as a hero because Stevens had been publishing extracts from Wallace's letters and had displayed some of the rarities he collected in the Amazon.

A major difference between the two books is that Wallace's biography has only one real protagonist; his family joins the story late in the book and Wallace's life (he married at 43). Enchanted by Daphne begins as the story of Peter Grant but soon develops (around one-third through the book) into the story of Peter and Rosemary Grant's research and, partly, the lives of their two daughters, Nicola and Talia. It might be interesting to read Rosemary Grant's recent biography One Step Sideways, Three Steps Forward (Grant, 2024) to compare perspectives. Since they met, the Grants have worked together in a way that makes it impossible to say which idea belongs to whom. For those who want to learn more about their scientific findings, a new edition of the book that synthesizes the Grants’ 40 years of research on Daphne island was published recently (Grant & Grant, 2024). Yet, their partnership as a family was more than scientific collaboration; it also influenced their career direction. For example, Peter turned down a professorship at Cambridge because there would have been no position for Rosemary. Together, the Grants have been a powerful and productive combo, and both managed to become impactful scientists. Because of the balance between their professional and personal lives, Grant's book radiates happiness, contains many family anecdotes, and achieves an equilibrium that makes the writing scientifically interesting, human, and funny. Such lightness is not present in the book on Wallace. However, it is not really a fair comparison because Grant's book is autobiography, whereas Costa narrates the life of Wallace often while explaining the cultural and historical context in which he lived.

Despite the family's minor role in Costa's book on Wallace, there was a crucial family intervention. We should thank Wallace's wife Annie for encouraging him to write The Malay Archipelago (Wallace, 1869). This book summarizes the 8 years during which Wallace traveled in Southeast Asia and the critical discoveries he made there. Wallace was already noticing boundaries that separate and potentially explain the distribution of species in the Amazon, but it was in Asia that everything started to make sense and where he put his theory into words.

One of his letters eventually reached Darwin, who was pushed by his friends to hasten publication of his results so he would be the first to bring the theory to light. Interestingly, Wallace seemed to be less concerned about matters of ownership because he later published a book titled Darwinism (Wallace, 1889), which probably did little to earn him the well-deserved recognition for his contribution to this theory. Wallace's work has been more appreciated posthumously. To be fair, we should not forget that when Wallace started advocating for social justice, he also turned to spiritualism. He wrote a paper on natural selection claiming divine intervention to explain the development of the human brain, which was devastating for Darwin.

Recognition for the Grants was not unusual; they received numerous awards for their work on finches in the Galápagos. One of the messages Peter offers at the end of the book is the role of the Dea Fortuna and his belief that things will always work out, even if sometimes in unexpected ways. These finches were at the mercy of El Niño after all. Their travels to attend award ceremonies occupy a substantial portion of the book and, although impressive, are less interesting than the accounts of their lives and research.

I read these books several times, at times liking one over the other. I knew some of the main results of Grant's research on the Galápagos, but I was unfamiliar with the scientist himself. I also learned numerous new things about Wallace. For example, I did not know that he campaigned against compulsory smallpox vaccination, researched extraterrestrial life (he rejected the possibility of life on Mars), and met John Muir while traveling in the United States and that they influenced each other. I also learned that he kept writing and publishing books until he was 90 years old.

Both books are beautifully written. The only serious and surprising weakness of both lies in their lack of effective maps. Grant did not provide any, whereas Costa offers them only at the beginning of the book instead of integrating them into the chapters. Nevertheless, these books should be read several times not only because they are enjoyable and rich in interesting content but also because both provide a picture of how unpredictable and exciting the life of a scientist can be. I could not help wondering whether ecology has dramatically changed today. Is the era of field exploration dead? How many researchers leave home for years of adventure, seeking patterns that reveal ecological processes? Are there still Wallaces and Grants out there performing long-term studies? I could not find the answers to these questions, but I may have found an answer to the question of whether a young and busy PhD student, postdoc, or professor should spend time reading biographies of these scientists. I believe they should because such people have lived inspiring lives and produced insightful results and because the excitement generated by fieldwork stories and discovery is contagious. Perhaps even more importantly, these books present two successful but almost opposite ways of doing science. Wallace, with his diversity of interests and the contradictions he embraced during his career, cannot be reduced to a single definition. Costa elegantly highlights this truth about Wallace's “multitudes” by borrowing Whitman's words from Song of Myself (Whitman, 1855). Grant, with his devotion to finches and Daphne for virtually his entire career, provides a contrasting approach. Wallace and Grant managed to understand geographically and temporally vast patterns through big- and small-scale observations, respectively. Perhaps the future of ecology lies in not losing the ability to make either.