Complex Systems Seminar<br>Extinction of Established Populations: A Physicist's View<br><b>Speaker: Baruch Meerson (Hebrew University, Physics)</br></b>

Speaker: Baruch Meerson (Hebrew University, Physics)

Extinction of an isolated population after maintaining a long-lived established community is a dramatic phenomenon. It ultimately occurs, even in the absence of detrimental environmental variations, because of the intrinsic stochasticity of birth and death processes. I will show how one can use a variant of WKB approximation (after Wentzel, Kramers and Brillouin) to evaluate the mean time to extinction of an established stochastic population. In this approximation the most likely path of the population to extinction is given by a separatrix (a heteroclinic orbit) of an underlying classical Hamiltonian.