Philip Ball - Shapes : Natures Patterns - A Tapestry in Three Parts.

Natures Patterns

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Philip Ball 2009

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First published 2009

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THERE is beauty to be found in regularity: the same element repeating again and again, typically with geometric order. There is no better example than the honeycomb, a miracle of hexagonal perfection. This sort of pattern is a lattice. On a leopards pelt, the lattice melts but a pattern remains: spots spaced at more or less equal distances but no longer in neat rows. There is a comparable order in stripes and concentric bands: a succession rather strictly enforced on the angelfish, but more loosely applied in the meandering, merging stripes of the zebra or of sand ripples. The means by which these natural patterns are constructed may tell us something about how the far more complicated forms of animals and plants are created by a progressive division and subdivision of space, orchestrated by nothing more than simple physical forces.

Pattern and Form

Building with Bubbles

Stripes in a Test Tube

Hiding, Warning, and Mimicking

Crystal Communities

The Mathematics of a Daisy

The Formation of Body Plans

AFTER my 1999 book The Self-Made Tapestry: Pattern Formation in Nature went out of print, Id often be contacted by would-be readers asking where they could get hold of a copy. That was how I discovered that copies were changing hands in the used-book market for considerably more than the original cover price. While that was gratifying in its way, I would far rather see the material accessible to anyone who wanted it. So I approached Latha Menon at Oxford University Press to ask about a reprinting. But Latha had something more substantial in mind, and that is how this new trilogy came into being. Quite rightly, Latha perceived that the original Tapestry was neither conceived nor packaged to the best advantage of the material. I hope this format does it more justice.

The suggestion of partitioning the material between three volumes sounded challenging at first, but once I saw how it might be done, I realized that this offered a structure that could bring more thematic organization to the topic. Each volume is self-contained and does not depend on one having read the others, although there is inevitably some cross-referencing. Anyone who has seen The Self-Made Tapestry will find some familiar things here, but also plenty that is new. In adding that material, I have benefited from the great generosity of many scientists who have given images, reprints and suggestions. I am particularly grateful to Sean Carroll, Iain Couzin, and Andrea Rinaldo for critical readings of some of the new text. Latha set me more work than Id perhaps anticipated, but I remain deeply indebted to her for her vision of what these books might become, and her encouragement in making that happen.

Philip Ball

London, October 2007

Pattern and Form

ARRIVING on Earth, the aliens approach the first thing they see and utter the familiar words: take me to your leader (). Like many jokes, this one offers a damning critique. It undermines the venerable and serious scientific quest to find life on other worlds, exploding the question of how would we know if we found it? by answering that we tend to imagine it will look like us.

Now, let me assure you that astrobiologists (as scientists who study aliens are called nowadays) are not really that foolish. They do not imagine for a moment that when we touch down on another inhabited world, we will be greeted by envoys who look like Leonard Nimoy. Indeed, if there is life in those parts of our own solar system that seem at all habitable (such as the subsurface seas of Jupiters icy moon Europa), it is most unlikely to warrant the description intelligent. And we may have to look hard and long to find it, precisely because we dont know what were looking for. Yet even if we know it is not going to be Dr Spock, we have trouble shaking the conviction that it will look something like the forms of life we have seen before.

Fig. 1.1: Do we inevitably expect life to look like us?

). But scientists have a rather more sophisticated view of life (although they still cannot agree on a universal definition of it), which gives them hope of distinguishing it from its inorganic context. They recognize some attributes of living systems that go beyond mere physical appearance, such as the fact that life tends to destroy the chemical equilibrium of its environment. Ill explain later what I mean by that, but lets say for now that its rather like watching a film in which all you can see are balls being juggled: you know that there is something out of frame that is keeping them in motion. Its true that some geological and astrophysical processes that dont involve life at all can also induce this disequilibriumbut nonetheless, searching for disequilibrium as a potential fingerprint of life seems a lot better than looking around for a loitering humanoid alien to whom you can say Take me to your leader.