Evolutionary Singular Strategies and the Adaptive Growth and Branching of the Evolutionary Tree

We present a general framework for modeling adaptive traitdynamics in which we integrate various concepts and techniques from modern ESS-theory. The concept of evolutionarily singular strategies is introduced as a generalization of the ESS-concept. We give a full classification of the singular strategies in terms of ESS-stability, convergence stability, the ability of the singular strategy to invade other populations if initially rare itself, and the possibility of protected dimorphisms occuring within the singular strategy's neighborhood. Of particular interest is a type of singular strategy that is an evolutionary attractor from a large distance, but once in its neighborhood a population becomes dimorphic and undergoes disruptive selection leading to evolutionary branching. Modelling the adaptive growth and branching of the evolutionary tree thus can be considered as a major application of the framework. A haploid version of Levene's 'soft selection model is developed as a specific example in order to demonstrate evolutionary dynamics and branching in monomorphic and polymorphic populations.