General Research Interests

My research program is aimed at achieving a deeper, mechanistic understanding of basic ecological and evolutionary processes. I aim to better understand the general underlying “rules of nature” that control the survival, growth, and reproduction in individual organisms, and then use these rules to make predictions about the structure and function of communities and ecosystems. To do so, I work in broad collaboration with scientists from many disciplines to develop simple, quantitative models, based on first principles, and then rigorously test these models with data from field or laboratory studies. I work in both terrestrial and aquatic ecosystems with a variety of different organisms. In fact, much of my research combines data from different organisms and ecosystems, often at broad spatial or temporal scales (i.e., macroecology). In the coming years, I wish to use a combination of experimental, theoretical and field-based approaches to address questions. This research helps to link species to ecosystems, genes to phenotypes, and also ecology to evolution. It has implications for current environmental problems such as global climate change. Three current focus areas of research are described below:

Controls on Individual Metabolism: This research focuses on how first principles of physics, chemistry and biology combine to constrain the physiology or life history of organisms. In particular, I focus on how the effects of body size, temperature, and resource supply constrain basic rate processes in individuals, particularly metabolic rate (B). This research falls under the heading of physiological ecology. For example, my colleagues and I have shown how the combined effects of body size and temperature explains much of the variation in metabolic rate for various taxonomic groups ranging from plants, to animals and microbes (Gillooly et al. 2001)(see Figure). Since metabolic rate controls many other biological rates and times, the simple equation describing the size and temperature-dependence of metabolic rate, , can be used to predict many other biological rates and times in individuals, including hatching rates and lifespans (Gillooly et al. 2002). This research has implications at all levels of biological organization and is the basis of our “metabolic theory of ecology” (Brown et al. 2004).

Linking Ecosystem Processes to Individual Metabolism: This research focuses on linking the nutrient cycling of carbon, phosphorus and nitrogen in whole ecosystems to the flux, storage and turnover of these important nutrients in individuals. In other words, this research aims to link species to ecosystems. By combining our metabolic framework with that of ecological stoichiometry, I aim to quantify the contribution of biota to biogeochemical cycles. For example, recent research by our group has shown that we can predict the concentration of RNA and phosphorus at the individual-level using this approach(Gillooly et al. 2005a). We also can predict many aspects of the global carbon cycle such as turnover rate (see Figure)(Allen et al. 2005). In the future, this research could have important implications for understanding the response of ecosystems to global change.

Linking Evolutionary Dynamics and Patterns of Biodiversity to Individual Metabolism: This research focuses on predicting rates of evolution based on rates of energy flux (i.e., metabolic rate) occurring in individuals. Specifically, this research first aims to develop models that predict rates of molecular evolution, and rates of speciation and extinction, based on the size and temperature-dependence of individual metabolic rate. I then aim to address how such evolutionary dynamics may contribute to patterns in biodiversity. For example, recent research by our group has shown that a metabolic approach can predict rates of neutral molecular evolution (Gillooly et al. 2005b). This research helps in understanding the origin and maintenance of biodiversity (Allen et al. 2002). It will involve both theoretical work and a series of laboratory experiments.