Compositional Evolution : Interdisciplinary Investigations in

vi List of Figures xiii List of Equations xvi List of Tables xvi Chapter 1 Accretive and compositional change in natural and artificial evolution 1 1.1 Exchange between evolutionary biology and evolutionary computation 2 1.1.1 Gradualism and the probability of large adaptive changes 2 1.1.2 Evolutionary adaptation and artificial optimisation methods 3 1.2 Accretive and compositional mechanisms 4 1.3 Complex systems with modular interdependency 7 1.3.1 Evolvability and algorithmic paradigms 7 1.3.2 Modular interdependency 10 1.4 The (un)evolvability of systems with modular interdependecy 14 1.5 Conditions for the adaptive advantage of composition 17 1.5.1 Composition based on sexual recombination 18 1.5.2 Composition based on symbiotic encapsulation 20 1.6 Impact for evolutionary biology and evolutionary computation 22 1.7 Related issues 26 1.7.1 Related issues in Evolutionary Biology 26 1.7.2 Related issues in Evolutionary Computation 28 1.8 Summary 32 1.8.1 Motives, research questions, and claims 32 1.8.2 Approach and outline of models 33 1.8.3 Contributions 35 1.8.4 Scope 36 1.8.5 Dissertation structure 37 Chapter 2 Accretion and Composition in Evolutionary Biology 40 2.1 The accretive model 40 2.1.1 Successive slight modifications/ gradualism 40 2.1.2 Evolutionary difficulty under accretion 42 2.1.3 Consequences of the accretive model 47 2.2 Compositional mechanisms 48 2.2.1 A spectrum of compositional mechanisms 48 2.2.2 Sexual recombination 49