The artificial ecosystem: number soup (part II)

T paper is a follow-up work about the number soup model (1). It elaborates more mathematical details; describes more general properties and gives different interpretations of the model in a more heuristic way; and lists some intriguing questions deserved to be investigated more. The paper is organised in the following way. Section 1 shows examples of demographic structures in different n-metabolite systems, aiming to give a feeling about how complex the interactions among species and how diverse an ecosystem could be. Section 2 discusses the properties of the ecological concept we put forward, the species loop, in more detail. Section 3 connects Gillespie Algorithm and the intuition that on average one unit time is the duration that each organism completes a life cycle. Section 4 compares Monod equation, an classic empirical law for microbial growth, with the growth rate of organisms I assumed in the number soup model. Section 5 describes another way of thinking the rules we used in the model about what a species excretes. Section 6 clarifies different types of cross-feeding, only one of which is tackled by the number soup model. Section 7 tries to interpret the model in the view of cooperators and cheaters, promoting sceptical thinking. Section 8 lists intriguing points and questions which are deserved to be investigated, associated with the number soup model, in the order of relevance and importance.