Demographic Noise

 

The overarching theme of my research is how uncertainties in birth, death and interaction events at an individual level can affect the behaviour of a system at the population level.

 

Fast-variable Elimination 

 

In order to tackle problems involving demographic noise analytically, I frequently make use of methods based on the elimination of fast-variables in a system.

 

Population Genetics

 

Population genetics was the first biological field to truly embrace the concept of demographic noise. Fundamental ideas developed in this discipline are still popular today, contributing not only to models of organism evolution but also the spread of language, ideas and cooperation.

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The Evolution of Sex

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From our mammal-biased point of view, it is easy to take sexual reproduction and the sexes themselves for granted. However there remain a number of questions regarding the evolution of sex that remain incompletely understood: How have systems of sex determination evolved? Why did sexes evolve? Why even did sexual reproduction evolve? In attempting to answer these questions, it is useful to look across the breadth of evolutionary possibilities offered up by nature, including: temperature controlled sex determination; Sexual reproduction sans sexes; Facultative (optional) sexual reproduction.

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Public Goods and Multicellularity

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Why should an organism contribute to the fitness of a group or population at the detriment of its own fitness? Evolutionary theory robustly predicts that mutant "cheats" who absorb common benefits but do not themselves contribute should drive an "altruistic" population to extinction. Yet nature is rich with apparently cooperative and social organisms. Understanding the evolution of this behaviour has fascinated biologists and ecologists for decades. 

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A similar dilemma faces individual cells in a multicellular complex. Multicelluarity has evolved independently multiple times during Earth's history, whether from the formation of cellular complexes or from cellular aggregation. Exploring the ecological conditions that may select for these mechanisms is an intriguing and challenging question that has ​yet to be fully understood.

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The Maintenance and Stability of Complex Ecosystems

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Ecosystems are the embodiment of a complex system, since their behaviour is difficult to understand from knowledge of its components alone. A question at the heart of ecology for decades has been a deceivingly  simple one - should increasing the complexity of an ecosystem make it more or less stable?

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