On Genetic Algorithms and Lindenmayer Systems

This paper describes a system for simulating the evolution of artificial 2D plant morphologies. Virtual plant genotypes are inspired by the mathematical formalism known as Lindenmayer systems (L-systems). The phenotypes are the branching structures resulting from the derivation and graphic interpretation of the genotypes. Evolution is simulated using a genetic algorithm with a fitness function inspired by current evolutionary hypotheses concerning the factors that have had the greatest effect on plant evolution. The system also provides interactive selection, allowing the user to direct simulated evolution towards preferred phenotypes. Simulation results demonstrate many interesting structures, suggesting that artificial evolution constitutes a powerful tool for (1) exploring the large, complex space of branching structures found in nature, and (2) generating novel ones. Finally, we emphasize that Lindenmayer systems constitute a highly suitable encoding for artificial evolution studies.