## evolution

*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.

**Lewis Dartnell**turns the universe into a matrix to model traffic, forest fires and sprawling cities.

**Charlotte Mulcare**uses milk to show how maths and stats can provide genetic answers.

*Plus*spoke to the cognitive psychologist

**Rosemary Varley**to find some answers.

**Paul Davies**has made an unusual move into the infant discipline of astrobiology. He tells

*Plus*about his interest in the big questions: what is life, how would we recognise aliens - and are they all around us?

Researchers have used mathematical modelling to understand the evolution of the influenza virus.