Tropical Leaves

Evolutionary Gaia Group

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We are an international research group of professional evolutionary theorists, modelers, ecologists, and philosophers working on the evolution of complex systems, including microbial assemblages, ecological communities, and the hypothesis of Gaia. 

Currently, members of our group are affiliated with Dalhousie University (Canada), the University of Exeter (UK), and the University of Sydney (Australia).

Research Projects

1. Persistence-based Selection - We develop an interpretation of selective fitness in terms of differential persistence, i.e., fitness as the capacity of an entity to survive. This view recasts units of selection as spatiotemporal continuous processes or lineages rather than individuals or groups of contemporary individuals.

2. Multi-Level Selection and Ecology - We make use of multilevel selection theory (MLST) to study ecological processes (i.e., non-selective random migration) in ecological communities and metapopulations. One of our goals is to provide a concrete example of evolution without reproduction in the context of MLST.

3. “It’s the song, not the singer” (ITSNTS) - This theory has been developed to legitimize and supplant claims that we and our microbiomes (“holobionts”) – or complex communities more generally – are units of selection. ITSNTS holds that it is the processes implemented, not the implementing taxa, that are the relevant units evolving through differential persistence.

4. Darwinizing Gaia - We are trying to re-formulate understandings of evolution by natural selection (ENS) in ways that Charles Darwin himself, and contemporary philosophers and biologists who are Darwinians, might accept.  We use elements from our previous projects to achieve this goal.


Neto, C., & Meynell, L (Forthcoming) Scaffold: A Causal Concept for Evolutionary Explanations Philosophy of Science 

Lean, C. H., Doolittle, F., &Bielawski, J. P. (2022) Community-level evolutionary processes: Linking community genetics with replicator-interactor theory PNAS 119(46): e2202538119


Neto, C., & Doolittle, F (2022) The Chemostat Model of Evolution by Persistence, and its Relevance to Clade Selection Philosophy of Science doi:10.1017/psa.2022.11

Inkpen S. A., Doolittle, W. F. (2022) Do Microbial Communities regenerate? A Philosophical Inquiry Chicago University Press

Tyler D.P. Brunet, W. Ford Doolittle, Joseph P. Bielawski (2021) The role of purifying selection in the origin and maintenance of complex function. Studies in History and Philosophy of Science Part A 87 125-135. DOI:

Lenton, T. M., Kohler, T. A., Marquet, P. A., Boyle, R. A., Crucifix, M., Wilkinson, D. M., & Scheffer, M. (2021). Survival of the Systems. Trends in Ecology & Evolution.

Inkpen, S. A., Doolittle, W. F. (2021) Adaptative Regeneration Across Scales. Philos Theor Pract Biol 13:1. DOI:

Lenton, T. M., Dutreuil, S., & Latour, B. (2020). Life on Earth is hard to spot. The Anthropocene Review, 7(3), 248-272.