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PHYSICS PHD DISSERTATION DEFENSE: Michael Pearce

Ph.D. Candidate:  Michael Pearce


Research Advisor:  Daniel S. Fisher

Date: Tuesday, Dec. 3, 2019
Time:  
3pm
Location: Clark S363

Title: Models of microbial dynamics: from genetic exchange to ecological interactions

Abstract: 

How can physics approaches illuminate evolutionary and ecological dynamics? This talk presents two stories of using physics-style toy models in these areas. 

 

Genetic exchange in microbial populations can be rare enough that evolution is almost entirely asexual. What is the benefit of such rare genetic exchange? In the first part, I'll present a minimal model to understand how the speed of evolution depends quantitatively on the rate of genetic exchange. The rates needed for initial speed ups are found to decrease as a power of the population size and the evolution exhibits spontaneous oscillations.

 

Fine-scale diversity within traditionally defined species is observed to be maintained over long timespans. How can ecological interactions lead to such coexistence? Previous approaches have required conditions less reasonable for closely-related strains. The second part introduces a model in which structured interactions allow such strains to coexist in a state of spatio-temporal chaos with broad distributions of abundances. The dynamics of many interacting strains are understood using methods from statistical physics.

December 3, 2019 - 3:00pm
Clark S363