Tropical rain forests have been called the "jewels of the earth" due to the rich diversity found in their flora and fauna. La Selva Biological Station in Costa Rica is a preserve where scientists conduct research on the rain forest's role in world ecology. Ants of many species enjoy nectar produced by Inga thibaudiana, a relatively small tree…

Leaves carry out photosynthesis in clusters of cells locally serviced by end-units of pipes that deliver water and take away sugar. The cells must be within diffusion distance of pores to exchange carbon dioxide and oxygen. Diffusion may set an upper limit on the size of an efficient cluster, and quasi-fractal branching of pipelines may set a…