The topology of evolutionary novelty and innovation in macroevolution

Sewall Wright's fitness landscape introduced the concept of evolutionary spaces in 1932. George Gaylord Simpson modified this to an adaptive, phenotypic landscape in 1944 and since then evolutionary spaces have played an important role in evolutionary theory through fitness and adaptive landscapes, phenotypic and functional trait spaces, morphospaces and related concepts. Although the topology of such spaces is highly variable, from locally Euclidean to pre-topological, evolutionary change has often been interpreted as a search through a pre-existing space of possibilities, with novelty arising by accessing previously inaccessible or difficult to reach regions of a space. Here I discuss the nature of evolutionary novelty and innovation within the context of evolutionary spaces, and argue that the primacy of search as a conceptual metaphor ignores the generation of new spaces as well as other changes that have played important evolutionary roles. This article is part of the themed issue ‘Process and pattern in innovations from cells to societies’.

A Novice's Biography of George Gaylord Simpson

George G. Simpson (1902-1984) had an enormously successful career for some fifty years during the middle of the twentieth century. Owing to his great intellect, especially his deep analytic skill and broad synthetic insight as well as his single-minded persistence, he produced a large body of published work that became an integral part of modern evolutionary theory. His high level of scientific achievement can be gauged by the number and quality of his publications, his institutional affiliations, his honors and awards, and the recognition he received in mainstream popular culture.1 Because Simpson was arguably the leading paleontologist of the last century and a major contributor to the ‘modern evolutionary synthesis’ I informed him of my biographical interest and asked for a personal interview. I sought further permission to interview his family, colleagues, and former students. For all interviews, I prepared a dozen leading questions, but also allowed interviewees to decide what was important. I encouraged tangential remarks and hence surprising insights were revealed. If possible, I corroborated what the interviewees told me; I did not take everything at face value. I always kept the emphasis on the content and character of Simpson's scientific accomplishments, avoiding ‘psycho-biography.’ I visited archives for unpublished documents—relevant personal letters, photographs, notes, newspaper clippings—and checked school and university records. I traveled to places where he grew up, attended school, was employed, and did field work. I divided the work into stand-alone articles, beginning with the easier and more obvious ones. I published these serially so they could later be revised, reassembled, and crafted into the final larger, unified biography. Doing research and writing in this way, I kept the longer-term project moving forward, making necessary course corrections as I went along. I thus established my credibility, advanced the research, and expanded the sources of information. Piece-meal publication satisfied deans and made possible a graceful escape if the project stalled, or I lost interest. However, seeing my work in print further motivated me to complete the task. Reviews were very positive, but sales more disappointing. Un succès estime!? (Laporte 2000a).

The Equally Wonderful Field: Ernst Mayr and Organismic Biology

Biologists in the 1960s witnessed a period of intense intra-disciplinary negotiations, especially the positioning of organismic biologists relative to molecular biologists. The perceived valorization of the physical sciences by "molecular" biologists became a catalyst creating a unified front of "organismic" biology that incorporated not just evolutionary biologists, but also students of animal behavior, ecology, systematics, botany——in short, almost any biological community that predominantly conducted their research in the field or museum and whose practitioners felt the pinch of the prestige and funding accruing to molecular biologists and biochemists. Ernst Mayr, Theodosius Dobzhansky, and George Gaylord Simpson took leading roles in defending alternatives to what they categorized as the mechanistic approach of chemistry and physics applied to living systems——the "equally wonderful field of organismic biology." Thus, it was through increasingly tense relations with molecular biology that organismic biologists cohered into a distinct community, with their own philosophical grounding, institutional security, and historical identity. Because this identity was based in large part on a fundamental rejection of the physical sciences as a desirable model within biology, organismic biologists succeeded in protecting the future of their field by emphasizing the deep divisions that ran through the biological sciences as a whole.