Abstract: The Green Earth Hypothesis
Plants account for 99.9% of the biomass on Earth. What is the explanation? The carnivore population is limited by the availability of prey, but why aren't there more herbivores, despite the fact that there is plenty of plants for them to eat? The Green Earth Hypothesis, formulated in 1960 by Hairston, Smith and Slobodkin, attempts to explain this appealing to evolution. Roughly speaking, plants have one major adaptation problem to solve: how not to get eaten. For this reason, they develop spikes, accumulate poisonous chemicals and employ other defensive strategies. Similarly with carnivores, at least those at the top of the food chain: their only problem is how to catch something (that is, someone) to eat. But herbivores have two problems: how to feed themselves and how not to get eaten. In the genetic race that results, they lag behind. It is more difficult for them to adapt and, as a result, there are fewer of them that available food could support.
A simple numerical model attempting to capture the essential features of this effect was introduced by a group of researchers in Warsaw, Poland---Dawidowicz, Kulik and Wrzosek. Their simulations, done using Matlab, yield results supporting the Green Earth Hypothesis. I will outline the model and the results of these initial simulations. I hope to get you interested in continuing this project by conducting more thorough simulations, possibly with more sophisticated models. The research would be coordinated with the Warsaw group. It addresses a fundamental question in evolutionary theory and may lead to exciting further problems.