Body size, geometry, longevity and metabolism: do plant leaves behave like animal bodies?

Given their differing geometry, evolutionary history and hierarchical position, plant leaves and animal bodies provide a useful comparison in evaluating the roles of size and geometry in the scaling of biological form and function. Metabolism and longevity scale similarly with specific surface area (surface area per unit mass) for both plant leaves and animal organs and bodies, indicating a fundamental allometry between geometry, area- and mass-based gas exchange and biochemical processes. By contrast, metabolism and longevity scale with size (mass) in animals but not in leaves. These findings provide evidence for the general phenomenon of geometrically based, but not size-based, scaling relationships in nature.