Ecology, evolution, & climate change: G. Evelyn Hutchinson and the founding of modern ecology
Often the most important discoveries originate in simple questions: Why are there so many different kinds of animals in lakes? Why don’t those animal communities settle down to a stable balance? Yale biology professor G. Evelyn Hutchinson (1903–1991) was one of the rare individuals who relentlessly ask the most basic questions, and today he is widely hailed for helping to shape the fields of modern biology and environmentalism, and furthering our understanding of climate change.
E.O. Wilson describes Hutchinson as the “founder” of modern ecology, and “one of the few scientists who could unabashedly be called a genius.” Stephen Jay Gould called him “the world’s greatest ecologist.” In his long Yale career Hutchinson was a teacher, mentor, and friend to renowned ecologists Robert MacArthur and Robert Odum, the writer Dame Rebecca West, anthropologist Margaret Mead, and over five decades of Yale undergraduate and graduate students. Biogeographer Jared Diamond wrote that Hutchinson and MacArthur’s early theoretical papers transformed ecology into a “structured predictive science that combined powerful quantitative theories with the recognition of widespread patterns in nature.”
Hutchinson was born in 1903 in Cambridge, England. His father was a professor of mineralogy at Cambridge University, and the young man’s first scientific mentor. An early interest in insects and aquatic life led Hutchinson to study science at Cambridge, but not at first in biology. He combined studies in mathematics, chemistry, and physics with an intense interest in zoology, and years later this breadth of knowledge in chemistry and mathematics is crediting with providing the foundation of his most important theoretical work.
Hutchinson began his academic career at Yale almost by accident. He arrived on campus in 1928 to take up a temporary teaching post in the Department of Zoology, and promptly irritated his new hosts with his enthusiasm for the then-radical theory of continental drift. Hutchinson soon became a respected teacher and researcher who constantly amazed his colleagues with the breadth and depth of his knowledge. Hutchinson’s biographer Nancy Slack relates a characteristic story: When barraged with questions by an especially eager group of students one colleague eventually threw up his hands and advised them to “Go see Hutchinson. He knows everything about everything.”
The vast collections of Yale’s Peabody Museum of Natural History attracted the young scholar. The natural history collections proved crucial to Hutchinson’s early fieldwork, and to his grand synthesis of evolutionary and ecological theory.
An early interest in aquatic life peaked his curiosity about lake systems around the world, as well as local lakes like North Branford’s Linsley Pond, prompting Hutchinson to ask such questions as: Why did some lakes support large and diverse populations, while others did not? Why were there so many different kinds of aquatic animals, even in small lakes? Why did seemingly identical ponds have such different fates?
Hutchinson was one of the first limnologists (specialist in lakes) to realize that studying the lake’s plants and animals alone were not sufficient to answer these kinds of questions, and that detailed quantitative studies of the lake’s physical chemistry and water conditions over the course of annual seasons might yield interesting answers.
Hutchinson and his students measured temperature gradients, water clarity, and geochemistry, and published the first major works that thoroughly described and analyzed the cycling of nutrients in lakes. Linsley Pond became the crucible for a new synthesis of careful empirical measurement and observation of all organic and environmental factors that might influence the biota of a lake system, combined with quantitative analysis of those results. It has been said that through this work Hutchinson and his students turned ecology from a largely descriptive enterprise into a theoretical and experimental science, described and reported in the language of mathematics.
In a 1957 paper cryptically titled “Concluding Remarks,” Hutchinson laid out the theory of ecological niches. He contended that an organism’s ecological niche is a summation of its role in a natural environment: how it survives, finds food and shelter, and interacts with other organisms. Hutchinson’s theory has influenced generations of biologists, and is the basis for our understanding that an ecosystem is a collection of plants and animals, where each species has a defined “job” — its niche — in a balance of coexistence, competition, and predation.
Having proposed the theory that multiple species in an environment sort themselves through competition into a stable “balance of nature,” Hutchinson later began to doubt whether ecosystems really tended toward a stable state. In his work at Linsley Pond Hutchinson documented many large seasonal and multi-year swings in the populations of lake plankton, far larger than niche theory alonecould account for. In his 1961 paper “Paradox of the Plankton” Hutchinson laid out the basis for much of current research on evolution and competition in natural systems, arguing that the complex and constantly varying seasonality of even relatively simple and small environments such as Linsley Pond assured that there would never be a simple balance in an ecosystem, and that natural communities at best achieve a very dynamic state of constant flux.
“Systems don’t achieve some happy balance — this idea of balance of nature may be misplaced. In fact these system are inherently not in equilibrium. Hutchinson used his observations over many years to demonstrate that there is no single equilibrium point at which one species can dominate” says David Skelly, director of the Yale Peabody Museum and professor of ecology.
Hutchinson was also one of the earliest scientists to warn about the dangers of climate change. In 1949 he wrote about the potential for human-created carbon dioxide to warm the planet, and in the early 1960s he testified before the U.S. Congress in an effort to raise awareness of broad climactic changes that were observed even then by most ecologists and field biologists. Hutchinson’s insistence on a broad, holistic view of ecology, climate, and human communities is credited with providing the scientific basis for the birth of the environmental movement in the 1960s.
Yale professor of ecology and evolutionary biology David Post sees this breadth of understanding as key to Hutchinson’s lasting influence in ecology: “Many of Hutchison’s early empirical research papers are now forgotten. They were important at the time, but not profound. Yet they served as the inspiration for Hutchinson’s true remarkable work, his synthetic work, the work we still remember today. Papers like the ‘Paradox of the Plankton’ came out of his deep understanding of these empirical systems. He had interests that ranged from evolution to ecology, and he gave rise to those fields, but he saw them as integrated, and therefore he understood things like eutrophication (pollution by excess nutrients) of aquatic systems by phosphorus in a very broad sense. He understood the effects could drive evolution, could drive communities and ecosystems. He understood that climate could have multifaceted impacts on ecosystems.”
“One of the things I love about the perspective Hutchinson could bring is that it’s still valid today — that the only way we’re going to address the ecological and evolutionary effects of climate change is to look at the effects of climate on nutrient cycling, on community organization, on evolution. Hutchinson’s skill at bringing that together was really important,” says Post.
Although he was renowned through most of his career as a master field biologist and theoretician, Hutchinson himself often said he was most proud of his nearly five decades of nurturing and mentoring his Yale students. Ecologist Robert MacArthur recalled his genuine enthusiasm for student’s ideas and observations, large or small — noting that there was a sign on Hutchinson’s office door in the 1950s that read: “Never discourage a student, for you are sure to succeed.”