ABSTRACT

The increasing use of biological forms and metaphors in art, engineering, architecture and design is based on assumptions about the efficiency, beauty and novelty of biological design, while the apparent efficiency and complexity of natural mechanisms has even been used by ‘intelligent designers/creationists’ to reject evolutionary orthodoxy. I will challenge these assumptions by presenting case studies of ‘unintelligent design’, biological inefficiencies and limitations. While biological structures are indeed marvellous in their design and intricacy, there are many design restrictions on biological tissue that man-made constructions can escape. The very nature of our carbon-based life forms restricts the temperatures, pressures and chemistry that can be employed in construction. Cells require a constant energy supply, while the need for nerves and blood supply means that many kinematic pairs are impossible in biological organisms. Biological scale is also restricted by this cellular basis; Reynolds numbers restrict the physical capabilities of biological organisms. The need to self-assemble, the fact that evolution can only act on pre-existing structures and can never start with a ‘blank page’, the need for variability; all place constraints on biological solutions. Selection drives the evolution of a beneficial trait until the marginal costs of continuing are balanced by the costs of not doing so. Evolution selects for traits leading to reproductive success rather than for longevity or health. Much of modern medicine is actually about treating the results of developmental and evolutionary compromises. Even some of our aesthetic tastes may be evolutionarily determined. I will discuss how inaccuracies (usually referred to as ‘natural variation’) are key to evolution and natural selection. How, paradoxically, far from being perfectly adapted biological machines, we may actually be selected and developed to be imperfect.

• Stuart Bunt, University of Western Australia