What had been dismissed as zoological cocktail-party banter was quickly heralded as a possible method to describe all life on Earth: algae, blue whales, entire ecosystems. The principles that Enquist and his colleagues--James Brown, a biologist at the University of New Mexico, and Geoffrey West, a physicist at Los Alamos National Laboratory--are discovering appear to reveal deep biological truths that can account for everything from the way cells consume nutrients, to the growth rates of trees, to CO2 fluxes from a rain forest. Today Enquist, 35, is using scaling laws to investigate how deforestation could affect global CO2 levels. "What happens to the rest of the biosphere if the Earth's resources and energy are increasingly shunted toward humans?" he asks.