DOI
10.1038/nature04624

Summary
Understanding the conditions that promote the maintenance of cooperation is a classic problem in evolutionary biology. The essence of this dilemma is captured by the ‘tragedy of the commons’: how can a group of individuals that exploit resources in a cooperative manner resist invasion by ‘cheaters’ who selfishly use common resources to maximize their individual reproduction at the expense of the group? In this framework, the authors of this study investigated this conflict through experimental competitions between isogenic cheater and cooperator strains of yeast with alternative pathways of glucose metabolism, and by using mathematical models of microbial biochemistry. In conclusion they showed that both coexistence and competitive exclusion are possible outcomes of this conflict, depending on the spatial and temporal structure of the environment. Both of these outcomes are driven by trade-offs between the rate and efficiency of conversion of resources into offspring that are mediated by metabolic intermediates.

Relevance for Complex Systems Knowledge
This study reports two experimental findings that are of general relevance for our theoretical understanding of social conflict: (1) cooperation can persist in a well-mixed population in the absence of kin-recognition, policing or rational behaviour and (2) spatial structure can promote the maintenance of cooperation.

Point of Strength
Although the complexity between biota elements cannot be reduced to a simple competition/cooperation model, competition for space and food is definitely a driver of the complexity, as competition is, especially to reduce the nutrients to assimilable forms. All this is well considered in this paper .