BIOLOGICAL DESIGN - A NEGLECTED ART

John Lenihan

OBE MSc PhD FlnstP FIEE FlBiol FRSE

In this talk I shall try to address three questions:

What is meant by biological design? Why is biological design a neglected art? Why and how should it be encouraged?

Before discussing biological design, I ought first to attempt a definition of design:

‘Design is the art of exploiting the properties of materials and their environment for the fulfilment of human needs or wants’

As we are assembled in a department celebrated for the application of advanced technology to problems of design, it may be useful to start by considering a notable design project which was implemented aeons .ago, in a way which still commands respect at least once a week. We do not have access to the archives of the design team (actually a one-man practice) but it is possible to make a plausible reconstruction of the original brief:

‘THE SUPER PRIMATE PROJECT

BASIC REQUIREMENT

A self-propelled device capable of moving freely over the Earth’s land

ENVIRONMENTAL SENSING CAPABILITY

Visual Power input range from ,101’ W to IO1 W

Auditory Power input range from l(j7 W to 10’ W

surface DATA HANDLING CAPABILIIY

PRIMARY MISSION Informadon transfer Maximum rate 25 bits/s

To gather fuel (plant and animal tissues) to provide (by combustion)

energy needed for movement

PERFORMANCE REQUIREMENTS

Speed Production models : Zm/s for several hours

High performance models : 5nds for a few hours

Start-up time 0.5 s

Energy Consumption Idling : 60 W Moving : up to 1.2 kW

Memory requirement On delivery - 100 million megabytes, expandable without futthcr hardware to 10 000 million megabytes

ADDITIONAL REQUIREMENTS

When the rate of working is too fast for the fuel combustion system, energy is obtained by the chemical transformation of structural material:

this process is reversible.

Ability to climb trees and jump ditches

- Self-repairing capability for minor damage

Efficiency 25% - Air conditioning and central heating

Automatic control of Stability _ Guidance

All models to be equipped with hi-fi stereo sound, 3-D colour video,

Internal temperature, to between 36°C and water meter, weighing machine and self-winding clock

38°C at all rates of working and all ambient Manufactured, entirely by unskilled labour, from only four basic temperatures between -40°C and 40°C materials - grit, glue, jelly and soup

Given before the Biological Engineering Society on Tuesday 24 September 1985 in the Engineering Department of the University of Cambridge

Reprints from: PI-of. J. Lenihan, University of Glasgow

0 1986 Buttetworth & Co (Publishers) Ltd 0141~5425/86/020091bO4 $3.00 J. Biomed Eng. 1986, Vol. 8, April 91

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When asked to fulfil this specification, engineers can do nothing - except to change the question. Consequently, our perception of the relationship between biology and technology has become rather one-sided and many important aspects of biological design have been neglected.

THE MEANING OF BIOLOGICAL DESIGN

This neglect has a long history, going back more than three centuries, to the time when Descartes asserted that the animal body is a machine. Succeeding generations of scientists and engineers have been enthusiastic in using the currently fashionable technology to explain the operation of natural mechanisms and processes. Harvey, drawing on the well-developed technology of hydraulics, saw the heart as a pump. Descartes, somewhat ahead of his time, described it as an internal combustion engine; vaporisation of blood in the ventricles caused the heart to expand and opened the outlet valves, allowing the vapour to pass into the lungs, where it was condensed. When steam power became fashionable in the 18 th century, Adair Crawford, a Glasgow physician, described experiments showing that respiration was a form of combustion. In 1825 when the scientific basis of modern chemistry had been developed, Berzelius wrote:

‘A living body is a workshop in which numerous processes take place, whose final result is the creation of phenomena, the totality of which we call life’

The theme which runs through all of these examples - nature imitating man - appears in many other contexts. The eye was at one time regarded as a telescope, then as a camera obscura and later as a simple camera Now we know that it is a very sophisticated camera, with the original zoom lens and through-the-lens exposure meter, giving instant th ree dimensional pictures in colour on reusable film. Helmholtz regarded the ear as a harp; later it became a telephone and now we know it to be a miniature stereophonic hi-b system. Bats move confidently in darkneis using sonar, bees find their way by exploiting the properties polarized light and birds use a magnetic aid to navigation.

What do we learn from these observations and

of

speculations? We learn that the interaction between biology and technology has for more than three centuries been dominated by efforts to explain biological design in the language of human technology - in other words to confirm or refute the assertion of Descartes that man is a machine. Scientists and doctors have generally found this assertion convincing, while philosophers and theologians have been more cautious. But the argument, though it has generated some fruitful insights, is futile, for two reasons:

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the structures and systems found in the animal body are, for the most part, too subtle to be adequately described in the language of human

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technology which, in the biological sense, is still primitive

when we ask Is the man a machine? we are bound to reach an affirmative answer, because all machines are models of man. Machines are devices made to perform tasks which would otherwise be carried out by the muscular or mental exertions of men, or of animals subservient to men. So when we compare the human body to a machine, we are merely looking in the mirror.

THE NEGLECT OF THE ART OF BIOLOGICAL DESIGN

Having laid the ghost of Descartes, can we use biological design as the source - and not merely the demonstration - of technological progress? Until quite recently, there were few examples of successful man-made technology derived from the study of biological systems. The most notable was achieved by Sir George Cayley, a Yorkshire landowner who, in 1804, enunciated the basic problem of aerodynamics:

To make a surface support a given weight by the application of power to the resistance of air.

He solved this problem by a study of bird flight, in the course of which he discovered the essential principles of lift, thrust, drag, stability and control. He put his ideas into practice in the design and construction of man-carrying gliders, which were demonstrated successfully - though perhaps reluctantly - by his servants.

A plant inspired Sir Joseph Paxton, the eminent architect of 19 th century England. He began his career as a gardener and was the first in Europe to succeed in cultivating the giant South American water lily, Victoria Regia This plant has delicate floating leaves, up to two metres in diameter but able to support a weight of 90 kg. The underside of the leaf carries a system of hollow ribs which give both strength and buoyancy. Having persuaded the water-lily to flower in the garden of his employer, the Duke of Devonshire, Paxton designed an elegant structure of metal and glass to protect it. This greenhouse became a model for the Crystal Palace which housed the Great Exhibition of 185 1 in Hyde Park Of this building Paxton wrote:

Nature was the engineer - nature has provided the leaf with horizontal and transverse girders and supports that I, borrowing from it, have adopted in this building.

There have been a few other inspirations of this kind - but the achievements of biological design are more easily recognised than imitated. Many of them involve materials and structures which change, without conscious intervention, in response to demands placed upon them. As D’Arcy Thompson observed many years ago:

The soles of our boots wear thin but the soles of

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siasm for organic farming, natural childbirth, health foods and alternative medicine, as well as in the popular desire to escape from reality in fantasy (such as science fiction) or superstition (such as astrology).

Why has enthusiasm for technology - the driving force of progress during the past two centuries- turned to disenchantment? Many reasons might be offered. In health care, for example, the growing support for unconventional ideas is not difficult to explain. A century ago, many people had confi- dence in quacks and charlatans, because traditional medicine was largely ineffectual and, indeed, often did more harm than good. But in our own time medicine and surgery have been all too successful. The major fatal diseases of earlier times - fevers, tuberculosis, diabetes and others - have been brought under control to a considerable extent. So more people live long enough to suffer from the chronic degenerative diseases of later life - cancer, mental illness, rheumatic afflictions and cardio- vascular disorders - which are difficult to manage and even more difficult to cure. In this situation many people have become disillusioned with tradi- tional medicine - even with medical technology which is demonstrably effective - and have turned elsewhere.

our feet grow thicker, the more we walk upon them.

A vein transplanted by the cardiac surgeon takes on the function of a coronary artery - and, after a while, changes its structure too, as its walls become thicker and less elastic.

This kind of adaptation to need, is commonplace in the biological realm. Man-made structures generally have little interaction with their environment; they are intended to go on doing the same job until they wear out through corrosion or friction. Biological materials are, of course, programmed to wear out, but while they last are often remarkably versatile. Skin, for example, has many functions - in respiration, heat exchange and environmental sensing and as the original shrinkwrap and self- sealing tank

Engineers, who are necessarily preoccupied with man-made technology, find performance of this kind difficult to analyse - and even more difficult to emulate. One of the reasons why progress from the natural to the artificial has been so slow is that we are only now appreciating some of the strategies that are so successful in the biological realm. Consider, for example, the eye. Judged as an optical instrument, the eye has many defects and is certainly not capable of delivering the performance that our visual sense actually achieves. It succeeds because of the subtle and sophisticated processing applied to the signals delivered by the relatively crude hardware. Our sense of hearing is enhanced in a similar way. In the external world, we have just reached the situation in which the cost of data processing has become very small, though hard- ware remains expensive. In biological design, a common strategy is to use limited resources in producing specialised hardware and to make up for the deficiencies by ingenious methods of data processing.

Another area in which we are catching up with nature has been illuminated by the molecular biologists. They have come close to fulfilling one of the basic objectives of all biology - the harmoni- sation of form and function. The enlargement of this bridgehead into the macroscopic domain is a challenging task to which biological engineers can make a distinctive contribution.

A STRATEGY TO ENCOURAGE BIOLOGICAL DESIGN

Why and how should the practice of biological design be encouraged? We should look at this question in a broader context. A distinctive characteristic of modern Western society is the growing hostility to technology, made evident in two ways - protest and rejection. Protest sometimes takes violent forms, but disenchantment is more often expressed in the movements and cults which reject sophisticated technology in favour of simple - even primitive - ways of life and thought. We see examples of this tendency in the growing enthu-

But there are more profound reasons for the situa- tion that I have been describing. The contemporary desire to reject technology and return to a simpler way of life is not new. It is an expression of the pastoral ideal - the belief that a simple life, without technology, commerce or industry, is man’s natural state, ensuring peace and happiness, and that it existed in a Golden Age from which society has deteriorated. This ideal was a favourite theme among the writers of Greece, Rome and almost every other ancient civilisation. Its most familiar exposition is found in the Eclogues and Georgics of Virgil. The symbolic landscape that he created - partly real and partly mythical - was, to his regret, already being eroded by the growth of the city, the misuse of political power and the general complexity of Roman civilisation.

To-day’s objections are more broadly based, because to-day’s technology is so much more pervasive. But they are the expressions of the same deep- seated anxiety. Freud asked:

How has it come about that so many people have adopted this strange attitude of hostility to civilisation?

He suggested that, though the stability of every community depends on the repression of powerful instinctive needs, our civilisation is more oppressive than those of earlier times. Ortega put this thought more concisely:

The world is a civilised one, its inhabitant is not.

The urge to oppose or to escape from the com- plexity of civilised life is ancient and respectable. It

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can be seen as a response to the corruption of simplicity - the destruction of innocence - by instruments of progress over which the individual has no control. The instruments have become more sophisticated since Virgil wrote, but the response that they evoke is much the same. Monitoring devices in the labour ward, space probes, food preservatives, intensive farming, nuclear power stations, computer data banks - these are the modern equivalents of the influences that have challenged the pastoral ideal through the centuries. In short, objections to progress are symptomatic of profound emotional needs: that is why they can so seldom be dispelled by appeal to reason. How can they be dealt with?

It is tempting to believe that the intellectual ability of modern man can improve on nature. Many of the anxieties evident in society to-day result from the conflict between this belief - which is one component of the idea of progress - and the instinctive yearning for a simpler and freer way of living.

I think that this Society- and the wider biological engineering community - can make a contribution to the resolution of the conflict. We should use our knowledge of science and technology, not to dis- parage or discourage enthusiasm for a style of living which seems closer to nature, but to achieve a better understanding of the principles and achievements of natural design, so that we may practise and apply them in the increasingly artificial (and therefore un-natural) world that we have created. Systems based on biological design will almost always be more efficient and should be

more acceptable in a world that is so increasingly disenchanted with conventional ideas and achieve ments of progress. Here, I think, we may see’ the justification for the encouragement of the neglected art of biological design.

SUMMARY

I ought now, perhaps, to offer a summary of what I have been trying to convey in this lecture - but I am haunted by the failure which attended an effort, by an eminent scholar of this city, to do something of the same kind many years ago. Sir John Sheppard, Provost of King’s, once gave a public lecture during one of the University’s ceremonial gatherings. His subject was the Trojan War. The large audience sat spellbound in admiration of his depth of insight, breadth of knowledge and grasp of detail. As he was leaving after the meeting, a young man came up to him and explained that he was a graduate studuent engaged in research on the economic consequences of the Trojan War. He had, however, been spellbound by the lecture and had been too engrossed to write anything down. Would Sir John be so kind as to lend him his notes so that he could make a summary of the lecture? “My dear chap”, said Sheppard, “I’d be delighted; here are my notes - use them as you wish and let me have them back whenever they have served your purpose”. So saying he handed the young man a postcard on which was written: Agamemnon _ Achilles - Agamemnon.

I hope that members of the audience won’t mind if I leave them to make their own summary of my remarks to which they have listened so patiently this evening.

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