Renowned British evolutionary biologists Rosemary and Peter Grant have dedicated their lives to studying Darwin’s finches. Over 40 years, they spent several months each year on the Galápagos Islands, meticulously tracking thousands of finches on two small islands. Their work provided real-time evidence of evolution by natural selection in the wild. Rosemary Grant’s new memoir, "One Step Sideways, Three Steps Forward," reflects on her unconventional path to becoming a biologist, living on the Galápagos with her family—including their two daughters for ten years—and the joy of collaborating with her husband. At 87, Rosemary is a senior research biologist, emeritus at Princeton University. Her memoir precedes a new edition of "40 Years of Evolution," the Grants’ classic account of their finch studies, set to be released later this year.
The Galápagos Islands, known for their unique species like giant tortoises and marine iguanas, played a crucial role in Charles Darwin’s development of the theory of evolution by natural selection. Darwin’s visit in 1835 and his collection of various songbirds, later identified as finches, led him to conclude that their diverse sizes and beak shapes evolved as adaptations to different food sources on the islands. Today, there are 17 distinct species of Galápagos finches and one on Cocos Island, all descending from a single ancestral species that likely came from mainland South America one to two million years ago.
The Grants chose to study Galápagos finches because their recent adaptive radiation made them ideal for observing species formation, as Darwin had suggested. Starting their fieldwork in 1973 on Daphne Major, they later added Genovesa, but eventually focused on Daphne to track individual finches more effectively. Their research involved banding birds, taking measurements, collecting blood samples for DNA analysis, monitoring food sources, and recording songs.
Living on the islands required bringing all necessary supplies, including water, which was sometimes delivered by boat. Their daughters, Nicola and Thalia, enjoyed the experience, contributed to the research, and conducted their own studies, leading to publications. Despite potential dangers, such as a near shark attack on Peter, the family adapted, even using shampoo with shark-repellent properties.
Contrary to Darwin’s expectation of slow evolutionary changes, the Grants observed rapid evolution. For example, the medium ground finch’s beak and body size decreased in response to competition during a drought. They also documented unexpected speciation methods, including hybridization and the formation of a new lineage from a single immigrant finch.
Their work emphasizes the importance of maintaining populations capable of natural change for species conservation. Genetic diversity and occasional interbreeding among finch species helped prevent extinctions during droughts.
Rosemary advises balancing professional life with parenting by not rushing and enjoying time with children, introducing them to diverse experiences. She never resented Peter’s career success, appreciating his support and their collaborative work.
