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Form, function, forests and fossils: sustainability revisited.

ON a hill high above Oban, a small port on the west coast of Scotland, there stands a structure that resembles a Roman amphitheatre. However, never in its history has a lion, a gladiator or, indeed, a Christian battled for their lives within its walls. In fact it has no function, and never has had. It is called McCaig's Folly, after John McCaig, the provincial banker who commissioned it. and it was built a mere one hundred years ago, fourteen hundred years after the fall of Rome. It could be said that it stands to remind us that form without function is folly.

Form follows function, or at least that is what Louis Sullivan (1856-1924), the American architect, and so-called father of the skyscraper, stated. This maxim has created a lively debate, reaching across many fields of human thought, from architecture to design and from town-planning to web development.

In architecture, it was the Venetian Franciscan and architectural theorist, Carlo Lodoli (1690-1761), who first discussed the relationship between form and function, stressing that nothing should be in the design that was not functional. This appears to be an extremely early version of what would become Utilitarianism, or Modernism. He was also credited with starting the organic architecture movement. Horatio Greenough (1805-1852), the American sculptor, developed these ideas, having studied the work of Lodoli, and of Georges Cuvier, who believed that anatomical form followed function. Ralph Waldo Emerson, a key figure in the transcendentalist movement in America, said that "Nature which created the mason now creates the house'. This idea would feed into the concept of natural architecture. Countering this approach, critics target the problem of a function existing without a form. Thus the form follows function dictum is seen as teleological.

While function tends to have had the upper hand in most areas, this is by no means the case in biology. Here, form dominates function in key topics such as taxonomy, phylogeny, evolution, diversity and conservation. This has had significant impacts upon how we understand our planet and in how we respond to the challenges that currently face the human race.

In this article, we will examine why form has become the dominant basis for so much of biology and the implications of this upon how we understand our planet. We will review what alternatives the functionalist school can offer, examining how it compares and contrasts to the formist school in significant ways. Finally, the repercussions of both approaches will be explored, in terms of how we address sustainability.

So how did form come to dominate biology? It is an interesting journey, and begins in ancient caves, where humans first drew images of the animals around them, some 30 000 years ago. From the earliest cave paintings of Chauvet in the Ardeche region of France, and the Altamira Cave in Cantabria, Spain, it is clear that humans had the capacity to accurately record morphology. Subsequently, the field of taxonomy developed, based on structure, both in terms of shape and colour.

Karl Linneaus revolutionized the way in which this was done. In fact he courted controversy at the time, using quite explicit sexual descriptions, such as 'nine men in the same bride's chamber, with one woman'! The German botanist, Johann Siegesbeck, referred to Linnaeus' work as 'lothesome harlotry', though Linnaeus, believing in revenge as a dish best served well and truly chilled, retorted with taxonomic vengeance, naming a small and insignificant little ruderal plant (Siegesbeckia) after his accuser.

This morphological basis for taxonomy meant that species were equivalent to forms. Indeed, when a species has not been formally identified, it is often referred to as a morphotype. Thus, diversity became a measure of forms or morphotypes. The number of different forms that a habitat possessed became a measure of its importance and significance. Form-rich habitats were celebrated, and form-poor habitats condemned. Indeed, the history of biological conservation is a journey steeped in form. How many conservation charities have a cute, fluffy or furry creature as their emblem? Humans are much more likely to help save the panda or the parrot than they are to help save the dung beetle or the slimy nematode.

It is a further irony that the organisms that have the greatest impact on our planet, the Bacteria and Archaea, are not even visible to the human eye, and, when magnified, consist, mostly, of only two forms, spheres and rods. These little creatures manage everything from atmospheric content (they are the main suppliers of nitrogen, which is 78 per cent of the atmosphere, and which prevents oxygen levels from reaching dangerous levels) to rainfall (acting as nucleating centres for precipitation, as revealed by Brent Christner in a recent article in Nature), and from recycling nutrients to lignin breakdown in herbivores (lignin is an extremely complex molecule where much of the sugar made by plants is stored), where 50 per cent of the energy obtained by the herbivore is released by the bacteria.

However, even more importantly, it was within the bacteria that most of the metabolic pathways were invented, which would later be passed onto the rest of life. They are, basically, formless, but very functional. However they are invisible to the naked eye, the equivalent of Adam Smith's invisible hands!

It was at the turn of the nineteenth century that the form/function debate really became a significant issue in biology. The zoologist E.R. Russell stated it this way: 'Is function the mechanical result of form, or is form merely the manifestation of function or activity? What is the essence of life - organization or activity"? Two natural historians based in France took opposing positions. Georges Cuvier (1769- 1832) stressed that form follows function while Etienne Geoffrey St Hilaire (1772-1844) firmly believed that function followed form.

Thoughts on form and function have occupied evolutionary biologists for many centuries. Jean Baptiste Lamarck (1744-1829) believed that function led form. The need for a particular function would result in the form changing. For example, the need to reach foliage led to the giraffe's neck elongating. Charles Darwin (1809-1882) turned this position upside down. Working from a taxonomy dominated by form, and relating these forms to each other by phylogeny, Darwin put forward a form-based theory of evolution, where tiny differences in forms (variation) were exposed to selection. Function follows afterwards, but it is the generation and then selection of form that comes first. Interestingly, the formist approach of Darwinian theory runs in opposition to the modernist, functional approach in design. The modernist approach suggests that designers should approach the solution by designing the best form to achieve the identified function (a Lamarckian idea), whereas the Darwinian architect would generate lots of different available designs, and see which one would best fit the challenge.

The adoption of form as the basis for understanding in biology is the natural outcome of empiricism and the scientific method. Never was a philosophy more thoroughly applied than Empiricism within science. Form fitted as an empirical currency. Forms could be built up of blocks. Function was too woolly, especially at higher levels of organization. Better the shadows on the cave wall, than the unknown world beyond. At least you could see shadows. Ultimately, form reduced to the gene, whose double helix became the iconic form of all biology, and it was selfish! Form had a personality, and displaced any requirement for a functional basis.

Form provided another very significant advantage over function. It ridded the stage of a god-like destiny. If function was seen as the driver, then this driver could be attributed to a deity. By having a randomly-generated set of forms, with the emphasis on random, there was no need for directed design. If there was a watchmaker at all, he was blind. There was no destiny, just a process of form generation and selection. One irony in this was the use of the term adaptation, which actually means to fit towards. Yet those who use this term freely would staunchly argue that there is no destination to evolution!

One of the significant consequences of reductionist thinking is that if it is a matter of building blocks, then engineering these blocks, the genes, would appear to be a strategy of useful value. If we can control the bricks, we can control the cathedral. Little building blocks can be put together to make all sorts of things, and to help solve the world's problems, such as food shortages and disease. In this new Utopia, we could envisage a Gattaca-like population of perfected humans, eating perfected food and living on an altogether perfected planet. (Those who are not film fans may wish to know that Gattaca is a 1997 science fiction film.) Form is controllable, it can be built and rebuilt, and we as humans have the technology to do this. We can re-engineer the imperfect forms produced by nature to build a better future.

We have applied our reductionist approach to ecosystem problems too. From the formist point of view, ecosystems are merely built of the organisms that occupy them. So if we have a problem, such as an unruly beast like the cane beetle (Dermolepida albohirtum), a pest of sugar cane plantations in Queensland, Australia, we can introduce something that will eat it, such as the cane toad (Bufo marinus). This form will eat the other form and all will be well. Two hundred million cane toads later, minus a number of native species now extinct or nearly so due to Bufo marinus, and this building block approach now looks questionable. Dumping large amounts of iron, one of the most limiting elements, into the oceans, in order to draw down carbon dioxide, is another example of such compartmentalized thinking.

We can examine the relative importance of form and function in evolution by examining the most significant evolutionary events on our planet: mass extinctions. Each mass extinction event has been caused by a significant drop in available energy. Either incident sunlight is blocked by clouds of dust, thrown up by volcanic activity or asteroid impact, or an albedo effect occurs (where significant ice covers the planet, reflecting back the sunlight). The situation spirals downwards as a result, with ever-decreasing available energy at the surface. As a result, primary productivity is dramatically reduced, causing the food web to collapse. It is akin to removing the bottom floor of a skyscraper. The tower will always fall.

Over time, incident sunlight begins to flow back, as dust clouds settle, and we now have a period of extremely rapid diversification. Energy is, once more, freely available and there is no shortage of nutrients, due, mostly, to the dead organic remnants of the extinction event. So competition, for space, energy and nutrients, is extremely low. Gradually as specification occurs and populations grow, the rate of evolution slows down. This has been referred to as punctuated equilibrium, with disturbance, extinction and diversification followed by a plateau or equilibrium. At equilibrium, competition is at its highest.

This is, to put it mildly, interesting. Darwinian theory, based on Malthus' work, puts competition at the centre of evolution. At high levels of competition, natural selection is at its rawest. Only the fittest survive, and the others are lost or rejected. So Darwinian theory would predict that at higher levels of competition we have the greatest evolution. However we actually observe the opposite to this. Evolution, in fact, slows down with increasing competition. The same thing is observed on islands. Here, we find that when organisms arrive on an island, they initially diversify rapidly, much more so than on the mainland. Darwin's tanagers (we now know that they weren't finches) came from the mainland, where competition was high, and were blown to the Galapagos Islands, where they had the freedom and space to diversify. There are examples throughout the scientific literature of this same phenomenon.

In other words, when selective pressures are low, we see diversification, while high selective pressure leads to an increase in rejection (because selection must occur simultaneously with rejection, in other words, if you select someone, you automatically reject someone else). This has the consequence of reducing the variation in the population, and thus reducing the possibility of diversification. Therefore natural selection can be described as a process that reduces variation. The less variation, the less evolution, therefore natural selection actually reduces evolution! There is no way around this, as increasing competition always leads to a reduction in diversification, according to the fossil record.

So in a mass extinction, the huge initial disruption opens up opportunity. After the KT extinction, 65 million years ago, that led to the demise of the flying reptiles and dinosaurs, birds and mammals emerged as the opportunists. The process is basically one of diffusion. In other words, evolution is a thermodynamic outcome. Imagine a gas in a sealed room. Open a door and the gas will diffuse into the second room. Open a door into a third room, and the gas will continue to diffuse. A good way in which to understand natural selection is as a closed door. When the door is open, evolution speeds up. Forms diffuse into the free space available. When the door closes, then the gas particles will reach equilibrium in the space they have.

So what does drive evolution? What makes it behave like a gas? Why does it go through the open door? I suggest that the driver is entropy, the same driver that lies behind diffusion. Matter explores available space, and this exploration is the process of the evolution of form. Thus, form is the outcome of thermodynamics, just as is function. Function can be seen as the flow of energy, while form is the consequence of this flow interacting with matter. Thus we can see form very much as a product of the interaction of function and matter.

Mass extinctions resemble a play by Shakespeare. In all the performances of this play, the text has remained the same, but the actors have changed. Each actor brings his or her own flair to the part, but the script ultimately determines their role. After each mass extinction event, new organisms take on the roles of carnivores, herbivores, detritivores and producers. However the overall script is the same. This is because the levels of organization are functional, and forms diffuse into the functional space, acting out their parts. If you don't say your lines, you won't be in the production. Thus the tight functional play resumes after each interruption, and is always the same. Individuals, populations, ecosystems and biomes re-establish as before, and are functionally identical. Thermodynamics writes the script.

The population of functional space is driven by diffusion. Ultimately, the laws of thermodynamics determine that the functional reality is restored to how it was before. The lessons of mass extinction are to do with the restoration of functional types, not the diversification of forms. Unfortunately, due to the dominance of form over function in biology, this has been, generally, missed. So when we try to understand evolution, we need to talk to the playwright, not the actor. In other words, it is thermodynamics that gives us the answers, not the phylogeny and taxonomy of form. Simon Conway Morris, the renowned palaeontologist, has compared evolution to an oil painting, writing, in The Crucible of Creation, It [Darwinian theory] has explained the nature and range of pigments, how extraordinary azure colour was obtained, what effect cobalt has and so on. But the description is quite unable to account for the picture itself.

So we can look at life on Earth as a single functional unit, expressing itself, through form, in myriad ways. This also helps explain why there are so many morphological expressions of so few functional types. Finally, by viewing mass extinctions from a thermodynamic. functional approach, we replace contingency of form, as put forward by Stephen Jay Gould, with functional continuity. Gould focused on forms, and wondered if lady luck had as much to do with the direction of evolution as anything else, or, maybe, more than anything else. He suggested that there was not a ladder of progress from start to finish in evolution through time, but rather, because of the intermittent wipeouts, there was at least a degree of luck as to what survived. The destruction was so cataclysmic, that it couldn't be adapted for, and so the survivors couldn't be predicted. He claimed that if we re-ran the film of life again, we would likely end up in a very different biology than we are in today. With function, no such contingency is needed.

In terms of the detailed forms that will replenish the vacated planet alter the next mass extinction, the functionalist and formist would agree that we cannot predict exactly what they will look like. However the functionalist can say a lot more than the formist. We would predict that the laws of thermodynamics would still hold, and thus we would expect that the Biosphere would function in the same way as it always has done, with primary producers, primary consumers, secondary consumers and detritivores all present. Their forms will result from an exploration of energetic space by morphological diffusion. As Keith Farnsworth and Karl Niklas wrote, 'We see evolution of design more as a process of diffusion into a space of possible solutions, than as a process of scalar optimization'.

We would also predict that, initially, under low natural selection pressures, evolution would be rapid, slowing down as selective pressure, due to competition, increased, exactly the opposite to what Darwin would have predicted, but in agreement with hundreds of millions of years of fossil evidence. Thus it would appear that function offers a much better explanation of past evolutionary events than does form.

Evolution happens not in the crowded back-alleys, but in the open market places. Unconstrained by the closed doors of competitive selection, that prevents diffusion, life after a mass extinction can explore morphological space, within the confines of function, driven by the second law of thermodynamics, as all diffusive processes are. Evolution shares this diffusion with developmental biology, physiology and indeed with the rest of the Cosmos. Not only are we Stardust, as Joni Mitchell famously sang at Big Sur, California, but we are under the same rules as all the other Stardust out there. Evolution is merely part of the greater cosmic dance of matter to the tune of thermodynamics.

Darcy Wentworth Thompson (1860-1948), often viewed by for-mists as one of their own, stated in his fascinating book, On Growth and Form (1917), 'We rise from the conception of form to an understanding of the forces which gave rise to it; and in the representation of form and in the comparison of kindred forms, we see in the one case a diagram of forces in equilibrium, and in the other case we discern the magnitude and the direction of the forces which have sufficed to convert the one form into the other'. Here, quite clearly, Thompson shows his true colours as a functionalist, 'rising from the conception of form' referring to the 'representation of form' and discussing the forces that convert one form to another.

If we envisage a room where perfume has been sprayed from a point source (like a perfume bottle), it will diffuse throughout the room until evenly dispersed. At this point the perfume is in a state of equilibrium. The Universe is heading in this direction, according to the second law of thermodynamics. Indeed every time energy change occurs, entropy is released into the Universe, and moves it one step closer to its ultimate destiny. A recent edition of the Philosophical Transaction of the Royal Society B (May 2010) dedicated itself to the principle of Maximum Entropy Production (MEP), which states that thermodynamic processes far from equilibrium (e.g. life) will reach a state where the maximum amount of entropy possible will be produced. We see this in a wide array of systems, from atmospheric circulation to vegetation heterogeneity. A ceiling is reached, constrained by the system. One of the clearest and most interesting examples of the Maximum Entropy Production principle, which is core to the final section on sustainability, is ecosystem succession.

Ecosystems develop over time, through a process called ecological succession. Succession is a natural, predictable, directional change in community structure over time. It was Eugene Odurri (1913-2002), the American ecologist, who said that succession is a developmental process. If we start on a beach, the sand accumulates, forming a series of dunes and slacks, that change through time (known as a chronosequence). Gradual change occurs in community structure, first with salt-tolerant species, then dune-building grasses such as marram. Following this, mosses and lichens move in and stabilize the surface. Next, more plants occur until a rich soil level builds up. Finally, a forest emerges.

Forests are the end point, or climax community. The forest will remain stable for hundreds of years, if undisturbed. The forest is my dream garden! You don't need to weed it, or plant it, or prune it. It is in balance with itself. It is the ultimate example of sustainability. This last sentence is why understanding succession is so very important. If we want a sustainable planet, then the answer lies in the forest, and the journey to this forest.

So what makes succession grind to a halt? What is the magic stop sign? In other words, what creates this sustainable ecosystem? The answer is found in thermodynamics. What we find is a gradual increase in entropy production through the earlier stages of the succession. Thus the driver that leads to change in the ecosystem is the second law of thermodynamics, with increasingly complicated structure generating increasing entropy, through increasing energy transformation. This is no runaway train, however. Eventually, a maximum level of complexity is reached, in the woodland. In other words, the forest represents the maximum entropy production possible. It can't increase any further, because it is constrained by its feedback interactions with itself, so the system becomes stable. Only if the forest is disturbed, resulting in a decrease in complexity and reduced entropy production, does it start along the increasing entropy ride again, back up to this maximum.

The reason the system is stable is because it is operating as a system. Reductionist, formist thinking cannot perceive this. It is an appreciation of the functional, thermodynamic ecology that allows us to understand how these systems work. We have become separated, intellectually, physically and philosophically, from our context. We now manipulate our planet, rather than work within its energetic rules. We view nature as a building, reducible to pieces that we can alter and rebuild. Yet because we have developed a reductionist, form-based ethos, we fail to understand the functional complexity of the system. Optimizing our own existence will not produce a sustainable system. Our actions make sense to us within the narrow lens of human self-focus. Looking down at our feet, we fail to see the destruction around us.

We are no longer within the ecosystem from whence we came, but have stepped out of the boardroom and set up our own, isolated, think-tank. We are now exceeding the maximum entropy production that would permit sustainable woodland to exist, with us as part of it. We are entropy generators par excellence. Think of all of the entropy released by an aluminium smelter, or the Haber-Bosch process, or a nuclear power plant. This all means that we can no longer expect a stable state to continue. It is our separation from our ecological context that has broken through the invisible ceiling. However, unless we step back into the system, and start behaving within this context, then there is no hope for a sustainable woodland.

We have created a garden, which needs weeding and pruning and fertilizing. Gardens demand constant and continuous management, as any of you who have wielded a garden spade will know! This is because gardens are attempting to defy the natural direction of ecological succession. Like little King Canutes, we stand in our backyards attempting to hold back the drive of nature, which wants to become woodland!

That can be our future, but I would rather live in a woodland, where the invisible hand of context leads to a sustainable planet, where we can put our feet up, lay down or hoes and pruning shears, and live within our means. It could well be said that rather than continuing to think outside our box, we need to get back into it!

Let me finish with a quote from Walter Teague (1883-1960), one of the world's leading industrial designers, taken from his book Design This Day, who summed things up rather well:

'The function of a thing is its reason for existence, its justification and its end, by which all its possible variations may be tested and accepted or rejected. It is a sort of life-urge thrusting through a thing and determining its development. It is only by realizing its destiny, and revealing that destiny with candor and exactness, that a thing acquires significance and validity of form. This means much more than utility, or even efficiency: it means a kind of perfected order we find in natural organisms, bound together in such rhythms that no part can be changed without wounding the whole'.

Dr Keith Skene is an evolutionary ecologist, author and Director of the Biosphere Research Institute. His latest book. Escape From Bubbleworld: Seven Curves to Save the Earth, published in September, is available from or directly from the publisher, at Contact the author on
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Author:Skene, Keith
Publication:Contemporary Review
Article Type:Essay
Geographic Code:4EUUK
Date:Dec 1, 2011
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