Salt Lake City may be the Crossroads of the West, but every city is a crossroads where people, goods, and ideas intersect. Similarly, urban ecology is a crossroads where ecological disciplines converge, from biogeochemistry and ecosystem science of material and energy flows through population, community, behavioral, evolutionary and human ecology. All of these approaches are essential to address the central question in human dominated ecosytems: How will the chains of unintended consequences unleashed by human actions filter through the entire system? I will present arguments to show that theorists are essential for this task, both to make sense of the data that reveals these chains and to synthesize them into a predictive framework.
Results/Conclusions
During my career, ecological thinking has broadened its purview from the "pristine" ecosystems of idealized study to include human-dominated ecosystems. The willingness to cross disciplinary boundaries and engage with complexity and uncertainty make ecological thinking powerful far from its area of origin. Physicists have taken their tools to address biological systems, and ecologists are now taking up similar challenges. For example, the study of cancer has been transformed by the central ecological ideas of heterogeneity, diversity of interactions, eco-evolutionary feedbacks, and feedbacks with the environment. This work creates an interesting contrast with "systems biology" that seeks to synthesize the parts list established by the successes of molecular and cell biology into a dynamical framework. In ecology, we tend to know "nothing about everything," that is, have a set of observations of the phenomena of interest with relatively little knowledge of the underlying mechanisms at the cellular or molecular level. In cancer biology, we instead know "everything about nothing," having full genome and transcriptome sequences for individual cells but with relatively little knowledge about the phenotypes or behaviors of those cells in their context. I will argue that theory coming from ecology is best poised to bridge this gap and further the unification of biology.
Contrasts between urban, and cancer ecosystems cast new light on each. Ecological communities are far less tightly knit and coevolved than cell collectives. Population regulation occurs largely through resource interactions and only in part through social and signalling interactions, while in the body signals play the primary role. I conclude by arguing that a key path forward is to think of these as different economic systems, where the tools of theoretical ecology are precisely those needed to unify different modes of thought.