Darwin y la tecnología

> Una breve nota en The Telegraph UK, escrita por el biólogo Steve Jones, describe las aplicaciones prácticas de las ideas de Darwin en sistemas tecnológicos complejos, como redes de telecomunicación.

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The new theories of evolution

Last Updated: 12:01am BST 17/07/2007

Darwin's ideas are being used by scientists to develop new drugs and plan phone networks, says Steve Jones

Last week I found myself answering hard questions about evolution in the echoing halls of an organisation established by an anti-evolutionist.

The new theories of evolution
Debate: question time at the Natural History Museum

The Natural History Museum (founder: Richard Owen, described by the normally mild Charles Darwin as "spiteful, extremely malignant, and clever") was hosting a "question time".

Beside me on the platform were the distinguished biologists, Richard Dawkins and Lewis Wolpert, and in front of us, beneath the vast skeleton of Dippy the Dinosaur, several hundred delegates of the annual GECCO meeting.

Nothing to do with extinct and terrible lizards or their modern relatives with sticky feet, but members of the Genetic and Evolutionary Computation Conference, whose main sessions were held at University College London.

Computers have long been used to model biological evolution (and Dawkins himself has played a part in this) but Darwin would have been amazed at the ways his ideas are being used by computer scientists to solve non-biological problems.

Evolution works, in the factory as much as the field; and military tactics, automatic music transcription and marine architecture - just some of the topics discussed - prove that Darwin's notion of unintelligent design can sometimes beat the most expert engineer.

The theoreticians use evolutionary robotics, genetic algorithms and their relatives to mimic the notion of descent with modification.

The equivalents of mutation, sex and natural selection crack challenges too complex for the fine scalpel of pure mathematics.

A set of rough and ready solutions compete within the machine, are randomly changed and reshuffled until, after many generations of breeding from the winners, a vastly improved version emerges.

On the wilder shores of algorithmia rest papers on The Induction of Fuzzy Rules with Artificial Immune Systems and on Using DNA to Generate 3D Organic Art Forms - a picture from the fertile computer of William Latham, of Goldsmiths College, London, one of the authors of that idea, can be seen above.

A whole group of intriguing conference titles turns on the Biblical injunction to "Go to the ant, thou sluggard; consider her ways, and be wise".

Much wisdom has emerged from studying those busy beings.

Ant colony optimisation, as the technique is called, turns on the fact that such insects exploit food in what appears to be an intelligent, but is in fact an entirely mindless, way.

One ant stumbles on a tasty item. It brings a piece back to the nest, wandering as it does, and leaving a trail of scent; a second tracks that pathway back to the source, making random swerves of its own; a third, a fourth, and so on until soon the active little creatures converge on the shortest possible route, marked by a highly-perfumed highway along which they scurry with every impression of planning.

As the food dwindles, one by one the animals give up, and the track slowly evaporates.

The computer scientists fill their machines with virtual ants and give them the task of finding their way through a maze or graph, leaving a coded signal as they pass until, just like the ants, the fastest route emerges.

The technique is used in planning the most efficient design of a phone network, the best use of the gates at Heathrow and the management of wireless messages through a grid of receivers. In the phone system, for example, each message leaves a digital scent-mark as it passes through a node and, as it builds up, the fastest track soon attracts the most traffic.

A few of the papers emphasised the lessons to be learned from nature; from real, rather than electronic, insects and, as a mere biologist struggling to understand computer-speak, that is a relief.

Ants do behave in a remarkably digital fashion. The ground around a colony is at its busiest on a warm day, with plenty of food around.

Its inhabitants decide en masse on the best strategy. A few go out as patrollers, returning to the nest only when they find some food. Back home, they are sniffed at by their fellows - and, as ant scent changes when they are out in the open the stay-at-homes can sense how many explorers are returning.

However, those domestic types need several hits on a patroller, spaced a few seconds apart, before they will venture outside. A shortage of food, or a hungry bird, means that not many of the wanderers return and the colony stays quiet; but once a threshold is reached a hungry mass suddenly pours out - and woe betide any tasty grub that gets in the way.

Even bacteria go in for a form of group-think based on mathematical rules.

A certain bug that gets into many hospital patients does little harm until it indulges its unpleasant talent of forming a sticky layer over a wound or a lung, with fatal results.

It's the swarming ant effect again: when the bacteria are rare there is no point in their holding hands with a neighbour to make a sheet because no more than a few cells would be linked. They divide instead.

As they do, they pump out a chemical signal, and as numbers rise that reaches a threshold. The billions of individuals then suddenly join into an adhesive and lethal film.

The latest idea, an exciting one in these days of antibiotic resistance, is to design drugs that block the signal molecule and might save the patient.

Strangely enough, one candidate for the job is garlic extract - which for bacteria, as for Britons, sends out a chemical message of mutual repulsion. Genetic algorithms are already used in drug development and the mathematicians will, no doubt, soon be on the garlic case too.

Evolution in the computer may soon overcome evolution in the real world, as bacteria and their digital equivalents use mutation and natural selection to defeat the challenges that human ingenuity throws at them.

That should prove the power of Darwin's theory to even the most hardened sceptic.
# Steve Jones is professor of genetics at University College London

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