Naturalist 25th Anniversary Edition

by Edward O. Wilson

  The mood of the era is caught in a personal letter I wrote to Lawrence Slobodkin, a young evolutionary biologist and newly acquired friend, on November 20, 1962. He had bravely journeyed from the University of Michigan to give a lecture on ecology.

  You will be glad to know that the students, both undergraduate and graduate, are nearly unanimous in their praise. They found the subject matter and your particular style exciting…. The faculty were less impressed. While quick to state that you were disturbingly original, your argumentation and data were not convincing. The reasons for this feeling are complex. My impression is that they arise in large part from the ancient prejudice against ecology, whose stereotype includes that it is not “solid” or rigorously experimental. Had a well-known biochemist, speaking on a more “solid” subject, given an exactly analogous lecture, he would have been cheered for his limber imagination and boldness.

  There is a final principle of social behavior to help keep these many developments in perspective. When oppressed peoples have no other remedy they resort to humor. In 1967 I composed a “Glossary of Phrases in Molecular Biology” that was soon distributed in departments of biology throughout the country and praised—by evolutionary biologists—for capturing the strut of the conquerors. My samizdat included the following expressions, which I have changed here from alphabetical order to create a logical progression of the concepts:

  Classical Biology. That part of biology not yet explained in terms of physics and chemistry. Classical Biologists are fond of claiming that there is a great deal of Classical Biology that individual Molecular Biologists do not know about; but that is all right because it is probably mostly not worth knowing about anyway, we think. In any case, it doesn’t matter, because eventually it will all be explained in terms of physics and chemistry; then it will be Molecular Biology and worth knowing about.

  Brilliant Discovery. A publishable result in the Mainstream of Biology.

  Mainstream of Biology. The set of all projects being worked on by me and my friends. Also known as Modern Biology and Twenty-first Century Biology.

  Exceptional Young Man. A beginning Molecular Biologist who has made a Brilliant Discovery (q. v.).

  First-rate. Pertaining to biologists working on projects in the Mainstream of Biology.

  Molecular Biology. That part of biochemistry which has supplanted part of Classical Biology. A great deal of Molecular Biology is being conducted by First-rate Scientists who make Brilliant Discoveries.

  Third-rate. Pertaining to Classical Biologists.

  First-rate, Brilliant, Wave of the Future … believe me, this was the phrasing actually used. Today those once oft-heard mantras clink with antique brittleness. The passage of thirty years has done much to close the divide between molecular and evolutionary biology. As I write, systematists, the solitary experts on groups of organisms, have unfortunately been largely eliminated from academic departments by the encroachment of the new fields. That is the worst single damage caused by the molecular revolution. Ecologists, pushed to the margin for years, have begun a resurgence through the widespread recognition of the global environment crisis. Molecular biologists, as they promised, have taken up evolutionary studies, making important contributions whenever they can find systematists to tell them the names of organisms. The surviving evolutionary biologists routinely use molecular data to pursue their Darwinian agenda. The two sides sometimes speak warmly to each other. Indeed, teams from both domains increasingly collaborate to conduct First-rate Work in what may now safely and fairly be called part of the Mainstream of Biology. The corridor language one overhears from molecular biologists has grown more chaste and subtle. Only hard-shelled fundamentalists among them think that higher levels of biological organization, populations to ecosystems, can be explained by molecular biology.

  I did not foresee this accommodation in the 1960s, caught as I was in the upheaval. Worse, I was physically trapped in the Biological Laboratories among the molecular and cellular biologists, who seemed to be multiplying like the E. coli and other microorganisms on which their finest work had come to be based. In buildings a hundred feet and a world of ideas away were the principalities and margravates of the senior evolutionary biologists. They were mostly curators and professors in charge of Harvard’s “Associated Institutions,” comprising the Museum of Comparative Zoology, the University herbaria, the Botanical Museum, the Arnold Arboretum, and the Harvard Forest. I envied them mightily. They could retreat to their collections and libraries and continue to be supported by venerable endowments bearing the names of nineteenth-century Anglo-Saxons.

  What I desired most was to emigrate across the street to the Museum of Comparative Zoology, to become a curator of insects, to surround myself with students and like-minded colleagues in an environment congenial to evolutionary biology, and never have to pass another molecular biologist in the corridor. But I held off requesting such a move for ten years, while Ernst Mayr was director. Perhaps I was overly timid, but the great man seemed forbiddingly stiff and cool toward me personally. There was also the twenty-five-year difference in age, and the fact that I had felt filial awe ever since adopting his book Systematics and the Origin of Species as my bible when I was eighteen. We have since become good friends, and I speak to him frankly on all—well, most—matters (he is still fully active in his ninetieth year as I write), but at that time I felt it would be altogether too brash to ask for haven in his building. My self-esteem was fragile then to a degree that now seems beyond reason. I felt certain that Mayr thought little of me. I dared not risk the humiliation of a refusal. I figured the odds at no better than fifty-fifty he would give it. When a new director, A. W. (“Fuzz”) Crompton, was installed and proved as approachable in personality as the nickname implies, I asked him for entry. Fuzz promptly invited me to the newly erected laboratory wing of the Museum (“You’ve made my day, Ed”) and soon afterward had me appointed Curator in Entomology. I do not doubt that the molecular biologists were also pleased to see me leave. One day near the end, while I sat at my desk, Mark Ptashne, one of the younger shock troopers of this amazing group, walked into my quarters unannounced with a construction supervisor and began to measure it for installation of equipment.

  By this time I had been radicalized in my views about the future of biology. I wanted more than just sanctuary across the street, complete with green eyeshades, Cornell drawers of pinned specimens, and round-trip air tickets for field work in Panama. I wanted a revolution in the ranks of the young evolutionary biologists. I felt driven to go beyond the old guard of Modern Synthesizers and help to start something new. That might be accomplished, I thought, by the best effort of men my age (men, I say, because women were still rare in the discipline) who were as able and ambitious as the best molecular biologists. I did not know how such an enterprise might be started, but clearly the first requirement was a fresh vision from the young and ambitious. I began to pay close attention to those in other universities who seemed like-minded.

  A loose cadre in fact did form. In January 1960 I was approached by an editorial consultant of Holt, Rinehart and Winston, a leading publisher of scientific texts, who asked me to referee the manuscript of a short book by Larry Slobodkin. The title was Growth and Regulation in Animal Populations. As I flipped through the manuscript pages I was excited by Slobodkin’s crisp style and deductive approach to ecology. He advanced simple mathematical models to describe the essential features of population dynamics, then expanded on the premises and terms of the equations to ask new questions. He argued that such complex phenomena as growth, age structure, and competition could be broken apart with minimalist reasoning, leading to experiments devised in the postulational-deductive method of traditional science. He went further: the hypotheses and experimental results could be greatly enriched by explanations from evolution by natural selection.

  Slobodkin was not the first scientist to advance this prospectus for the invigoration of ecology, but the clarity of his style and the authority implied
by a textbook format rendered the ideas persuasive. It dawned on me that ecology had never before been incorporated into evolutionary theory; now Slobodkin was showing a way to do it. He also posed, or so I read into his text, the means by which ecology could be linked to genetics and biogeography. Genetics, I say, because evolution is a change in the heredity of populations. And biogeography, because the geographic ranges of genetically adapted populations determine the coexistence of species. Communities of species are assembled by genetic change and the environmentally mediated interaction of the species. Genetic change and interaction determine which species will survive and which will disappear. In order to understand evolution, then, it is necessary to include the dynamics of populations.

  With this conception in mind, and my hopes kindled that Slobodkin would emerge as a leader in evolutionary biology, I wrote an enthusiastic report to the editor. A short time later I approached Slobodkin himself, suggesting that the time had come to produce a more comprehensive textbook on population biology. Would he be interested in writing one with me? In such a collaboration, he might introduce population dynamics and community ecology, while I added genetics, biogeography, and social behavior. The material would serve as an intermediate-level textbook. It would also promote a new approach to evolutionary biology founded on ecology and mathematical modeling.

  Slobodkin said he was interested. He would talk the matter over with me. Soon afterward we met in Cambridge to outline our prospective work. We went so far as to draw up individual assignments in the form of chapter headings.

  Slobodkin was then an assistant professor at the University of Michigan. A rising star in the admittedly still depauperate field of American ecology, he was later to move to the Stony Brook campus of the State University of New York, where he founded a new program in evolutionary biology. His reputation as a researcher has been securely based on a series of eclectic studies conducted before I met him and in the years immediately following. He studied the red tide phenomenon, the periodic population bloom of toxic dinoflagellate protozoans that poison fish and other marine life. He pioneered the measurement of energy transfer across trophic levels in ecosystems by the use of the bomb calorimeter. In the realm of theory, he elaborated the concept of a balancing relationship between the “prudent predator” and “efficient prey.”

  During the years to follow, I never failed to find Slobodkin’s physical appearance arresting: red-haired, alternately clean-shaven and dramatically mustachioed, an ursine body relaxed in scholar’s informality. Not given to easy laughter, he preferred ironic maxims over funny stories. His conversational tone was preoccupied and self-protective, and to a degree unusual in a young man tended toward generalizations about science and the human condition. It was leavened in the company of friends with discursive sentences and fragments of crude humor, seemingly contrived to throw the listener off balance, especially when combined with Delphic remarks of the kind philosophers use to stop conversations. These latter asides implied: There is more to the subject of our banter, much more; see if you can figure it out. Slobodkin in fact was a philosopher. I came to think of him as progressing through a scientific career to a destiny somewhere in the philosophy of science, where he would become a guru, a rabbi, and an interpreter of the scripture of natural history. Some of our friends complained that his persona was a pose, and perhaps it was to some degree, but I enjoyed Slobodkin’s subtle and penetrating mind, and his company. Not least, we were opposites in cultural origin, which made him all the more interesting to me. He was a New York intellectual, a Jew, as far in every dimension of temperament and style as it is possible to get from the sweat-soaked field entomologist I still fancied myself to be, then, in the early 1960s.

  Slobodkin was heavily influenced by his Ph.D. adviser at Yale, G. Evelyn Hutchinson, himself as different from Slobodkin and me as Larry and I were from each other: our relationship formed an equilateral triangle. Born in 1903, the son of Arthur Hutchinson, the Master of Pembroke College at Cambridge University, Evelyn—“Hutch” to those who dared call him an intimate—was a creation of British high-table science. True to the Oxbridge prize Fellow tradition, he never bothered to earn the doctorate, but instead trained himself into a polymath of formidable powers. He was a free spirit, an eclecticist who proved brilliant at fitting pieces together into large concepts. He never seemed to have met a fact he didn’t like or couldn’t use, somewhere, to start an essay or at least place in a footnote. He began his career as a field entomologist studying aquatic “true bugs” as experts call them—members of the order Hemiptera—and especially notonectid backswimmers. He worked as far from home as Tibet and South Africa. Then he turned to pioneering research on algae and other phytoplankton of lakes and ponds. He broadened his scope to include the cycles and stratification of nutrients on which life in these bodies of water depends. He was among the first students of biogeochemistry, a complex discipline combining analyses of land, water, and life. Still later, after becoming professor of zoology at Yale in 1945, he turned to the evolution of population dynamics, which also became Slobodkin’s forte.

  Hutchinson’s insights were deep and original, and, notwithstanding that such tropes have been worn to banality through overuse, he deserves to be called the father of evolutionary ecology. Among his notions that proved most influential was the “Hutchinsonian niche.” Like most successful ideas in science, it is also a simple one: the life of a species can be usefully described as the range of temperatures in which it is able to live and reproduce, the range of prey items it consumes, the season in which it is active, the hours of the day during which it feeds, and so on down a list as long as the biologist wishes to make it. The species is viewed as living within a space defined by the limits of these biological qualities each placed in turn on a separate scale. The niche, in short, is an n-dimensional hyperspace.

  Hutchinson’s independence was such that he remained unperturbed by molecular triumphalism; at least I never heard of his protesting in the manner of his colleagues in Harvard’s overheated department. In his later years he metamorphosed gracefully from field biologist to guru, seated in his office with wispy white hair and basset eyes. Beside him presided a stuffed specimen of the giant Galápagos tortoise. In a teaching career spanning nearly three decades, he trained forty of the best ecologists and population biologists in the world to the doctoral level. They included Edward Deevey, Thomas Edmondson, Peter Klopfer, Egbert Leigh, Thomas Lovejoy, Robert MacArthur, Howard Odum, and, of course, Larry Slobodkin. They all seemed to admire and love the man, and to have drawn strength and momentum from his example. Fanning out across the country to represent the many growing fields of ecology, they exerted a crucial influence in American biology.

  I asked several after they became my friends what “Hutch” did to inspire such enterprise in his disciples. The answer was always the same: nothing. He did nothing, except welcome into his office every graduate student who wished to see him, praise everything they did, and with insight and marginal scholarly digressions, find at least some merit in the most inchoate of research proposals. He soared above us sometimes, and at others he wandered alone in a distant terrain, lover of the surprising metaphor and the esoteric example. He resisted successfully the indignity of being completely understood. He encouraged his acolytes to launch their own voyages. It was pleasant, on the several occasions I lectured at Yale before Hutchinson’s death in 1991, to encounter him and receive his benediction. Head bobbing slightly between hunched shoulders, a wise human Galápagos tortoise, he would murmur, Wonderful, Wilson, well done, very interesting. It would have been pleasant to stay near him, the kindly academic father I never knew. I came to realize that the overgenerous praise did not weaken the fiber of our character. Hutchinson’s students criticized one another, and me as well, and that was enough to spare us from major folly most of the time.

  Hutchinson and Slobodkin were then what today are called evolutionary ecologists. In my formative years they caused me to try to become one as w
ell. Through them I came to appreciate how environmental science might be better meshed with biogeography and the study of evolution, and I gained more confidence in the intellectual independence of evolutionary biology. I was encouraged to draw closer to the central problem of the balance of species, which was to be my main preoccupation during the 1960s, as the molecular wars subsided to their ambiguous conclusion.

  chapter thirteen

  ISLANDS ARE THE KEY

  DURING A SEMINAR BREAK AT THE 1961 MEETING OF THE American Association for the Advancement of Science, held in New York’s Biltmore Hotel, Larry Slobodkin told me that there was someone I had to meet, someone we should ask to be another coauthor of the book on population biology. Two months had passed since we had first met to discuss our joint venture. “It’s Robert MacArthur, and he’s a real theoretician—very bright. I think we need someone else closer to pure theory, with a better mathematical background, to help with the book.”

  MacArthur, I learned, was a thirty-year-old assistant professor at the University of Pennsylvania. He had received his Ph.D. under Evelyn Hutchinson in 1957. After a year spent at Oxford studying with the British ornithologist David Lack, he had begun to move swiftly into a brilliant career. But neither Larry nor I could have guessed on that day we waited for him just how brilliant, that in one decade he would come to rival Hutchinson in influence. MacArthur was to bring population and community ecology closer to genetics. By reformulating some of the key parameters of ecology, biogeography, and genetics into a common framework of fundamental theory he set the stage, more than any other person during the decisive decade of the 1960s, for the unification of population biology. Then he was cut down by a fatal renal cancer, and became a legend. Today one of the most coveted honors for midcareer researchers in evolutionary biology is to be invited to give the MacArthur Lecture of the Ecological Society of America.