insight for curious the mind
the nature issue | Nov 2012
sCienCe and nature Collide Why nature holds the answer to sciences greatest mysteries
BranChing out A new class of plant hormones
Breaking nature’s Code Where does order and regularity come from?
contents: 03
editor’s letter
12
Catching it
17
soapbox science
20
instability
24
Cosmology
32
Viral research
40
Biosecurity
42
toxicology
59
Biology and ideology
66
a Fractal life
68
Why symmetry Matters
72
growing trouble
74
random harvest
80
in focus: Your Views
52
Nature’s Code
04
26
38
Branching out
Collision
Flower Power
a new breed of plant hormones is dicovered causing a new insight in to how plant growth and interaction can be manipulated.
Why nature is and has been so vital to science. We look at fractal shapes and the Mandelbrot set to explore this.
Powerful plants we look at 27 plants that could save your life. nature provides food and remedies that everyone should know about.
Where does the order and regularity within nature come from? We take a closer look to discover if these natural patterns are chaotic, spontaneous or something much more precise. Find out why plants are natural mathematicians.
nature’s code Do natural patterns really have anything in common or are they just coincidence? nature is full of patterns. When taking a closer look we can see a form of regularity, even in trees, leaves and cracks. But are these pattern or form? are they structured or chaotic or disorderly? some scientics believe the natural world is formed by a code, the golden ratio, a universal law. is the appeareance of nature’s patterns just a simply a natural coinsedence? either way there is still much more to be uncovered about the order of the natural world. insight // 15
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the forces of nature have conspired to produce such a pattern without any blueprint or design
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When taking a closer look regularites start to appear
F notice all kinds of patterns around us, not just in space but in time: the repeating patterns of night and day, of the four seasons, the patterns in a Bach fugue or in the rhythm of a trotting horse. We speak of patterns of behaviour, and it is sometimes said that the whole of science is about recognizing patterns in the behaviour of nature. i’m going to talk here primarily about patterns in space, and with identical or near-identical elements that recur in some regular arrangement. But that can mean many things, and i can really do no more than explain my terms by example, and to assert that, even if we cannot say precisely what we mean by a pattern, we know one when we see one. and the most curious thing about natural patterns-indeed, the central consideration of their same, in systems that might seem to have nothing at all in common with one another. We have seen that already: the hexagons of Fingal’s Cave put us in mind of the hexagons of the honeycomb, but why should this hexagonal pattern crop up in both cases? Because of the code or something else. elsewhere too: we’ve already seen the bubble raft, but here also is a pattern formed in a convecting chemical reaction, where the blue and yellow correspond to regions of the mixture of chemicals that is one of the drawings of microscopic sea creatures called radiolarians made in the late nineteenth century by the biologist ernst haeckel.
this is a simplistic way of portraying darwin’s theory and it would certainly be simplistic to say that this is how biologists see the living world today. But in thompson’s time there was a sense in which darwinism was the deus ex machina, the magical force that could be invoked to explain everything. thompson pointed out that. no matter how ingenious and inventive evolution was, in the end an organism had to work. its components had shape of a bone or a cell or a shell can’t be arbitrary, just as the shape of a bridge or a skyscraper can’t be arbitrary. Form, to put it in the slogan of the Bauhaus, follows function. that’s why, for example, the iguanodon and the kangaroo have a long heavy tail: as a counterbalance for the long heavy body and neck. it’s why the metacarpal bone of a vulture’s wing can be resembles the Warren’s truss, the engineering structure familiar from cranes: this is the ideal way thompson showed that haeckel’s science based showed radiolarians, with their delicate mineral exoskeletons, can be related to foams, and an open explained on the new assumption that the mineral is precipitated at this wide intersection of the pink bubble-like organic vesicles.What’s more, thompson, said, biological form and pattern is not just a question of static mechanical engineering: these things have to grow. a bridge doesn’t have to expand in all directions, but a plant does. ‘everything is what it is’, he said, ‘because it got that way.’ that’s why, after all, the book was called on growth and Form can be seen on the shell.
in macro photographs geometric shapes are visible and repeated to form patterns
Branching patterns: tree, river, lung, veins, cracks. now these are very interesting. are they pattern or form? are they regular or disorderly? they don’t have the geometric repetitive regularity of a honeycomb, but some of these structures do indeed turn out, on close inspection, to be made up of identical elements that recur again and again - but of recursive branching pattern a little more orderly in order to arrive at one of the most familiar and the big question is: do these patterns really have anything in common, or is the similarity in appearance just coincidence? this question tantalized scientists like Johannes kepler and the it was head-on was a scottish zoologist named d’arcy Wentworth thompson (1860-1948) in 1917 thompson published his masterpiece, on growth and Form, which collected together all that was then known about pattern and form in nature in a stunning synthesis of biology, natural history, mathematics, physics and engineering. stephen Jay gould has called this “the greatest work of prose in twentieth-century science”. Peter Medawar went on to investigate this further and noticed this.
We can see some striking patterns in even more advanced organisms: the swarms that are formed thing about these structures is that they are more to maintain their collective form. We’ve all seen birds swooping and diving together at dusk, and it has been a long-standing puzzle how they manage to do it. how do they stay in formation? are they following a leader? that’s what some ornithologists used to think, but no one could ever identify which bird the leader was. and in fact it became clear that the birds’ reaction times just weren’t fast enough for them all to be responding to a single leader, copying and repeating this. it’s only in the past few years that enough understanding has accumulated about collective behaviour to explain swarming. all you need, it turns out, are rules governing the local behaviour of the birds. that’s to say, each bird needs only to respond to its near neighbours, manouevering so as to stay close to them and to keep moving in the same average direction but to avoid collisions. here’s a snapshot of a computer model that invokes rules like this. if you set loose a group of virtual birds programmed to behave this way.
he was desperately keen to rationalize the shape hexagonal regularity of the bee’s honeycomb by appealing to simple physical forces: to surface tension pulling the soft wax into shape just like a bubble raft. Biology, however, is more complicated. We now know that bees do make the comb like so many construction workers erecting a building: they place each piece of wax carefully, using special organs to measure the angles relative to a set of organs to engineer the thickness of the cell walls very accurately. they even manage to construct the correct tilt angle of the cell channel, which slants down below the horizontal so that the honey doesn’t run out. When it comes to the living world, we’d be unwise to assume that all these patterns with these ingredients, his has a computer model showed how characteristic, gently curved trails emerge spontaneously. are they just blind,unpredictable, spontaneous.
‘Close up, you can see the regularity, of
natural pattern, in other words, its seems
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appreciated, and it was an idea so powerful that some biologists had seemingly come to the only conclusion that they needed nothing else. For every question that one could ask about biological shape and form, there seemed to be the one single answer: natural selection. Why does this creature or that plant look or grow the way it does? natural selection! the form has obviously been selected beone that does the job best. it had become tempting from which only the best were selected. this is a simplistic way of portraying darwin, and it would certainly be simplistic to say that this is how biologists see the living world today. But in thompson’s time there was a sense in which darwinism was the deus ex machina, the magical force that could be invoked to explain everything. thompson pointed out that. no matter how the ingenious and inventive evolution was, in the end an organism had to work. its components had to the particular, all of biology happens out all the organisms grow by now taking in energy. they are a self-organized product of many footfalls.
it was an idea so powerful that some biologists had seemingly come to the conclusion that they needed nothing else. For every question that one could ask about biological shape and form, there seemed to be a single answer: natural selection. Why does this creature or that plant look the way it does? natural selection! the form has obviously been selected the one that does the job best. it had become the
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there is still plenty to be uncovered about nature’s patterns... the engineer’s perspective on biology that d’arcy thompson provided was sorely needed. use mathematics. today many biologists do that without a second thought. But many others don’t. there is still some suspicion and dare i say fear of maths in biology: so-called ‘theoretical biology’ has been deemed a faintly disreputable subject. i think that even the most entrenched molecular biologist is starting to realise that now, faced with an increasing mountain of increasingly the old quantitative data on genes and their interactions, this has to change to create order. But it’s instructive to see how thompson wasn’t always right. he was desperately keen to rationalize the hexagonal regularity of the bee’s honeycomb by appealing to simple physical forces: to surface tension pulling the soft wax into shape just like a bubble raft. Biology, however, is more complicated. We now know that bees do make the comb like so many construction workers erecting a building: they place each piece of wax carefully, using special organs to measure gravity. they use another set of organs to engineer the thickness of the cell walls very accurately, to a tolerance of two thousandths of a millimetre. they even manage to construct the correct tilt angle of the cell channel, which slants down at 13 degrees.
insight // 21