Metabolic scaling and the evolutionary dynamics of plant size, form, and diversity: Toward a synthesis of ecology, evolution, and paleontology

A central goal of evolutionary biology is the development of a general predictive theory that incorporates the various forces structuring biological diversity. In this article, we argue that a focus on allometry and metabolic scaling theory provides the basis to begin to mechanistically link and understand patterns observed at ecological and evolutionary timescales. To make our case, we draw on and review several recently published papers and present new analyses. We argue that together, this synthesized work supports the notion that selection has maximized the scaling of resource exchange surfaces (e.g., photosynthetic surface areas) yet simultaneously minimizes the scaling of transport times and resistances. As a result, the scaling of plant metabolism, in turn, has profoundly influenced the evolution and ecology of plant form, function, and diversity, probably since the inception of the chlorophytes. In particular, we discuss preliminary support for the notion that stabilizing selection for 3/4-power scaling of metabolism, in addition to competition for similar limiting resources, has led to the emergence of regular ecological patterns that have likely been prevalent throughout plant evolution.