Effective Fitness as an Alternative Paradigm for Evolutionary Computation II: Examples and Applications

In paper I of this series we reviewed the recent development of an alternative paradigm for evolution on a fitness landscape–effective fitness–which offers an intuitive way to understand population dynamics as flows on an effective fitness landscape when genetic operators other than reproductive selection play an important role. In this article we demonstrate the utility of the concept using several simple analytical models and some more complex models that we simulate numerically. In particular, we show that effective fitness offers a qualitative and quantitative framework within which the phenomenon of induced symmetry breaking of the genotype-phenotype map may be understood. As explicit examples we consider: the violation of the building block hypothesis in non-epistatic landscapes; self-adaptation of genetic algorithms in time-dependent fitness landscapes and the appearance of evolutionary robustness as an emergent property in the evolution of language. In all cases we demonstrate that effective fitness offers a framework within which these diverse phenomena can be understood and in principle quantitatively studied.