Theory

We work on the evolutionary origins and consequences of species diversity. On origins, we model speciation in organisms such as bacteria that do not conform to the usual sexual lifestyle considered by most theories of speciation. We are particularly interested in when species boundaries should evolve to be strict versus leaky. On consequences, we devise models to predict evolutionary dynamics in species assemblages, especially for bacterial communities structured via overlapping and complementary use of metabolic resources. At broader scales, we have developed models of how selection and ecological limits shape large-scale diversity patterns, and whether there might be evolutionarily-significant units above the species. Mostly we use computer simulations due to the inherent complexity of problems involving multiple species and non-standard evolutionary assumptions. We also use coalescent theory to devise new methods for delimiting species from mixed population and phylogenetic samples.

References

Sheppard, R.J., Barraclough, T.G, Jansen, V.A.A. 2021. The evolution of plasmid transfer rate in bacteria and its effect on plasmid persistence. American Naturalist 198: 473–488

Barraclough, T.G. 2019. The Evolutionary Biology of Species. Oxford Series in Ecology and Evolution. Oxford University Press, Oxford.

Barraclough, T.G. 2019. Species matter for predicting the functioning of evolving microbial communities – an eco-evolutionary model. PLoS ONE.

Schmutzer, M., Barraclough, T.G. 2019. The role of recombination, local versus global gene pools, and flexible genomes in the ecological speciation of bacteria. Ecology and Evolution. 9: 4544-4556

Jordan, S.M., Barraclough, T.G., Rosindell, J. 2016. Quantifying the effects of the break up of Pangaea on global terrestrial diversification with neutral theory. Phil. Trans. R. Soc. Lond. B. 371: 20150221

Lawrence, D., Barraclough T.G. 2016. Evolution of resource use along a gradient of stress leads to increased facilitation. Oikos 125:1284-1295.

Fujisawa, T., Aswad, A. and Barraclough, T.G. 2016. A rapid and scalable method for multilocus species delimitation using Bayesian model comparison and rooted triplets. Systematic Biology. 65: 759-771.

Barraclough, T.G. 2015. How do species interactions affect evolutionary dynamics across whole communities? Ann. Rev. Ecol. Evol. Syst. 46:25–48

Humphreys, A.M., Barraclough, T.G. 2014. The evolutionary reality of higher taxa in mammals. Proc. R. Soc. Lond. B. 281: 20132750.

Fujisawa T, Barraclough TG. 2013. Delimiting Species Using Single-locus Data and the Generalized Mixed Yule Coalescent (GMYC) Approach: A Revised Method and Evaluation on Simulated Datasets. Syst Biol. 62: 707-724.

Barraclough, T.G., Birky, C.W. Jr., and Burt, A. 2003. Diversification in sexual and asexual organisms. Evolution. 57, 2166-2172