Organisms shape their own environment, which in turn affects their survival. This feedback becomes especially important for communities with a large number of species. How to understand this ecological feedback has long been recognized as an important question of community ecology. Using statistical physics methods we will present an analytical description of the classical ecological model of resource competition at equilibrium for a well-mixed population. The focus will be on the functional consequence of ecological dynamics, namely, the environment that a community shapes for itself. We will show that the highly diverse ecosystems present a phase where the community environment is fully decoupled from the outside world. Then, we will focus on the study of the model under different conditions, modifying the resources provided to the ecosystem and the survival conditions of the species. This will show that under certain conditions a number of species greater than the number of supplied resources can survive.