Issue 46

March 2008
Evolution is the main theme of this issue. With Darwin's anniversary year not too far off, we find out how to reconstruct the tree of life and how to spot the fingerprint of natural selection. We report on the rapidly melting Arctic, bound to destroy much of evolution's achievements, and explore the maths used in ice and ocean models. And we have a look at cellular automata, simple mathematical models that can evolve surprisingly complex behaviour. Plus you can learn how to best distribute money amongst your employees without evolving envy.
The Arctic ice cap is melting fast and the consequences are grim. Mathematical modelling is key to predicting how much longer the ice will be around and assessing the impact of an ice free Arctic on the rest of the planet. Plus spoke to Peter Wadhams from the Polar Ocean Physics Group at the University of Cambridge to get a glimpse of the group's work.
Next year is a great one for biology. Not only will we celebrate 150 years since the publication of 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.
According to Darwin, natural selection is the driving force of evolution. It's a beautifully simple idea, but given the thousands of years that are involved, nobody has ever seen it in action. So how can we tell whether or not natural selection occurs and which of our traits are a result of it? In this article Charlotte Mulcare uses milk to show how maths and stats can provide genetic answers.
Lewis Dartnell turns the universe into a matrix to model traffic, forest fires and sprawling cities.
Bonuses are a fact of business life. Last year the Guardian newspaper calculated that the cash rewards paid to London's financial chiefs comfortably outstripped the UK's entire transport budget. With such large sums at stake, envy is bound to raise its ugly head, nver a good thing for company morale. So how should you decide who gets how much? Steven J. Brams suggests a method that's not only fair, but also encourages honesty.
It's easier than you think
  • The league table lottery
  • Plus and presidents

This is the second part of our new column on risk and uncertainty. David Spiegelhalter, Winton Professor for the Public Understanding of Risk at the University of Cambridge, continues examining league tables using the Premier League as an example. Find out just how much — or how little — these simple rankings can tell you.

Rupa Patel never wanted to be a financial engineer — she wanted to be a maths teacher. However, her skills in conveying difficult mathematical concepts to others, as well as a love of maths, enticed her into the exciting field of financial mathematics. Now she models risk, travels Europe and occasionally finds time to herself to examine the maths of her job in detail.
This issue's teacher package brings together all Plus articles on probability and statistics, exploring anything from maths in the dock to games of chance. It also has some handy links to related problems on our sister site NRICH.
Crack a code with Enigma
This recently released DVD contains three films on fractal geometry, all directed and produced for a general audience by Nigel Lesmoir-Gordon.
This review looks at two books on one of the most important, and most difficult, open problems in mathematics: the Riemann hypothesis.
The Poincaré conjecture is one of the few mathematical results that has managed to catch the interest of the mainstream media.