## medicine and health

**David Spiegelhalter** and **Mike Pearson** explore how risk can be spun and there's an interactive animation for you to have a go yourself.

The European Science Foundation backs systems biology

**Chris Budd and Cathryn Mitchell**look at the maths that isn't only responsible for these medical techniques, but also for much of the digital revolution.

*On the origin of species*, but also 200 years since the birth of its author, Charles Darwin. At the heart of Darwin's theory of evolution lies a beautifully simple mathematical object: the evolutionary tree. In this article we look at how maths is used to reconstruct and understand it.

Mathematicians lead effort to build common model of the immune system

**David Spiegelhalter**, Winton Professor for the Public Understanding of Risk, gives

*Plus*his take on uncertainty.

A new Bayesian network helps predict the severity of the disease