Studying the evolutive and adaptative mechanisms of prokaryotes is a complicated task. As organisms cannot be easily studied ``in vivo'', it is necessary to consider other methods. We have developed the RAevol model, a model designed to study the evolution of bacteria and their adaptation to their environment. Our model simulates the evolution of a population of artificial bacteria in a changing environment, providing us with a insight on the strategies that digital organisms develop to adapt to new conditions.

We focus on the principles of the regulatory networks of the artificial organisms. Experiments are conducted on populations of artificial bacteria under conditions of stress. We study the ways in which organisms adapt to environmental changes and examined the strategies they adopt and topological characteristics of evolved networks.