Niels Bohr Institutet > Kalender - det sker på NBI > 2009 > Small system dynamics

Small system dynamics

Midway colloquim by Pia Cordsen

Small networks or 'motives' are the building blocks of large networks such
as genetic signaling proteins, ecological and economic systems.
Understanding simple motif dynamics can be a first step to understand the
large networks.
Here is presented an investigation of ecologically inspired motives
consisting of only 3 interacting species, by finding their symbolic
dynamics.
In this context 'symbolic dynamics' means a characterization of the system
dynamics in terms of maxima and minima of the species densities.
Examples of the symbolic dynamics found when exploring the parameter space
of the Hastings-Powell model are presented along with a set of rules for
allowed symbolic dynamics transitions.
Two other 3-species motives are presented, one motif with 2 predators and
1 prey, the other with 2 preys and 1 predator. It is shown how the
symbolic dynamics can provide an easy way to determine which of two
competing species is 'the better', and where coexistence is impossible.