Oceanographers may soon know what happens on the seafloor when it's too cold for such reef-building corals to grow. Traditionally, plant ecologists thought that the size of a given plant determined the relationship between how big it gets and how many plants can live together in the same area. NSF-funded researchers Brian Enquist and James Brown of the University of New Mexico have found that the thinning law can be better understood by studying the size of individual plants and the amount of energy they use. If available energy levels are the same, it turns out that the law works for all species, whether plant or animal. The mathematical description of this plant thinning law is identical, whether the species is an animal or a plant, says Brown.
Common theories can explain many unifying aspects of biology.
Put more simply, there's only so much to go around, whether you're an animal or a plant.