Competition-driven evolution of organismal complexity

Non-uniform rates of morphological evolution and evolutionary increases in organismal complexity, captured in metaphors like "adaptive zones", "punctuated equilibrium" and "blunderbuss patterns", require more elaborate explanations than a simple gradual accumulation of mutations. Here we argue that non-uniform evolutionary increases in phenotypic complexity can be caused by a threshold-like response to growing ecological pressures resulting from evolutionary diversification at a given level of complexity. Acquisition of a new phenotypic feature allows an evolving species to escape this pressure but can typically be expected to carry significant physiological costs. Therefore, the ecological pressure should exceed a certain level to make such an acquisition evolutionarily successful. We present a detailed quantitative description of this process using a microevolutionary competition model as an example. The model exhibits sequential increases in phenotypic complexity driven by diversification at existing levels of complexity and the resulting increase in competitive pressure, which can push an evolving species over the barrier of physiological costs of new phenotypic features.Comment: Open PDF with Acrobat to see movies, 22 pages, 9 figure

A Process Modelling Success Model: Insights from a Case Study

Contemporary concepts such as Business Pro cess Re-engineering and Process Innovation emphasize the importance of process-oriented management concepts as a businesses paradigm. Large scaled multimillion-dollar implementations of Enterpri se Systems explicitly and implicitly state the importance of process modeling and its contribution to the success of these project. While there has been much research and publications on alterna tive process modeling techniques and tools, little attention has focused on post-hoc evaluation of actual process modeling activities or on deriving comprehensive guidelines on ‘how-to’ conduct process modeling effectively. This study aims at addressing this gap. A comprehensive a priori pro cess modeling success model has been derived and this paper reports on the results obtained from a detailed case study at a leading Australian logistics service provider, which was conducted with the aim of testing and re-specifying the model

On the evolutionary emergence of predation

In models for the evolution of predation from initially purely competitive species interactions, the propensity of predation is most often assumed to be a direct consequence of the relative morphological and physiological traits of interacting species. Here we explore a model in which predation ability is an independently evolving phenotypic feature, so that even when the relative morphological or physiological traits allow for predation, predation only occurs if the predation ability of individuals has independently evolved to high enough values. In addition to delineating the conditions for the evolutionary emergence of predation, the model reproduces stationary and non-stationary multilevel food webs with the top predators not necessarily having size superiority.Comment: 24 pages, 5 figures, typos correcte