Next NAME/Alergic: Hywel Williams, Wed 7th May, ARUN401

There will be a joint Alergic/NAME (New Approaches to Modeling Evolution & Ecology) on Wed 7th May, 16:30, ARUN401 when Hywel Williams from the Earth System Modeling Group, University of East Anglia will be presenting:

Environmental regulation in a network of simulated microbial ecosystems

The Earth possesses a number of regulatory feedback mechanisms involving life. In the absence of a population of competing biospheres it has proved hard to find a robust evolutionary mechanism that would generate environmental regulation. It has been suggested that regulation must require altruistic environmental alterations by organisms and would therefore be evolutionarily unstable. This need not be the case if organisms alter the environment as a selectively neutral by-product of their metabolism, as in the majority of biogeochemical reactions, but the question then arises: why should the combined by-product effects of the biota have a stabilising, rather than destabilising, influence on the environment? In certain conditions selection acting above the level of the individual can be an effective adaptive force. Here we present an evolutionary simulation model in which environmental regulation involving higher level selection robustly emerges in a network of interconnected microbial ecosystems. Spatial structure creates conditions for a limited form of higher level selection to act on the collective environment-altering properties of local communities. Local communities that improve their environmental conditions achieve larger populations and are better colonisers of available space, while local communities that degrade their environment shrink and become susceptible to invasion. The spread of environment-improving communities alters the global environment towards the optimal conditions for growth and tends to regulate against external perturbations. This work suggests a new mechanism for environmental regulation that is consistent with evolutionary theory.

All welcome!