Biological evolution is a fascinating subject which can be fully understood
only if it is approached from many different angles. In this talk I will
present my personal point of view on how physics can advance our
understanding of biological evolution. I will focus on three problems in the
evolution of bacteria I have been working on recently. I will begin with a
simple, statistical-physics model of the evolution of antibiotic resistance.
This is a timely and important problem because drug-resistant, pathogenic
bacteria are becoming a major health hazard. I will show that resistant
bacteria can rapidly emerge in environments with spatially non-uniform drug
concentration such as our bodies during antibiotic treatment. Towards the
end of my talk, I will briefly discuss the evolution of metabolic networks
in bacteria and biological evolution in bacterial colonies growing on solid
substrates.