Steve Jones on natural selection

From The End Of Evolution?
"LET'S TURN TO THE second issue: natural selection. People often think of natural selection as something almost magical. But it isn't. It's extraordinarily simple. I first witnessed natural selection taking place in a soap factory in Liverpool in the 1960s, where I worked after leaving school.

Detergent was made then as it is made now: by forcing boiling hot chemicals at great pressure through a nozzle. As the mixture zooms out, the pressure drops, and it breaks into a vapour that is sucked away and a powder which is then sold as detergent.

The nozzles were a damn nuisance. They were inefficient, kept blocking and made detergent grains of different sizes.

Unilever and various other companies hired mathematicians and physicists in an attempt to improve the situation. But they didn't do very well; it turns out that the physics and maths of the transition from liquid to powder is quite difficult to understand.

So, almost in despair, they turned to the lowly biologists and asked if they had anything to add. What the biologists did was to apply Darwinian natural selection.

They made 10 copies of the nozzles, with slight changes absolutely at random. Some nozzles were longer, some shorter, some had a bigger or smaller hole, maybe a few grooves on the inside. But one of them improved a very small amount on the original, perhaps by just one or two per cent.

Based on the improved nozzle, they made another 10 slightly different copies, and repeated the process. After only 45 generations – which would be an utterly trivial instant in evolutionary time – they had a nozzle that worked many times better than the original. This was without any forethought of any kind, only by a simple application of evolutionary mechanisms."

A nice discussion of the nozzle example in Tim Hartford's Ted talk
Trial, error and the God complex