Theoretical physics applied to living systems
Date:
Saturday, September 21, 2013 - 10:30
Venue:
Theoretical Physics, 1 Keble Road, Oxford OX1 3NP
Overview:
The physics of living matter was explored in this second event: addressing current ideas surrounding active materials - such as cells and microorganisms - and systems, discussing how these systems naturally provide a testing ground for theories of non-equilibrium statistical physics, and how evolution finds solutions in hyper-astronomically large search spaces.
Living Matter: a theoretical physics perspective
Video podcast | Presentation (PDF)
What is life? This is the title of a celebrated book by Erwin Schroedinger, in which he draws attention to the fact that living organisms are in fact physical systems made of interacting components. Today we know that living systems can be viewed as self-organised active soft matter that is maintained away from equilibrium ``just the right way''. This lecture discusses this notion, and provides a framework in which we can begin to understand essential processes of life from a physical point of view. Such an understanding could allow us put together simple systems - from basic ingredients that we fully understand - that would exhibit the kind of active behaviour we find in living systems.
Motility in living matter: from molecular motors to bacterial swarms
Video podcast | Presentation (PDF)
Active materials, such as microorganisms, cells and molecular motors, continuously transform chemical to mechanical energy. In the past few years there has been a surge of interest in understanding the properties of active matter. This is made possible by recent advances in imaging, computational power and nanotechnology, and is driven by the aim of designing biomimetic micro- and nano-machines. On a more fundamental level, active matter is meant to exist out of equilibrium, and hence provides a testing ground for the theories of complexity and non-equilibrium statistical physics. This lecture describes how bacteria swim, and introduces mesoscale turbulence in dense, active suspensions.
How evolution designs living matter
Evolution proceeds by random mutations that generate variation, which, in turn is acted on by natural selection. Most of evolutionary theory has focussed on how natural selection affects variation in populations. But, in the words of Hugo de Vries: "Natural selection can explain the survival of the fittest, but it cannot explain the arrival of the fittest." In this talk I show, for a number of simple biophysical systems, that variation is highly biased to produce certain outcomes over others, and that this bias strongly affects evolutionary outcomes.