Vicarious selection is a novel idea and it provides the answers to even more subtle problems. Fig genes and wasp genes are partners, locked together in a fast waltz through geological time. Most of the many species of fig have, as we've seen, their own private species of wasp. Figs and their wasps have evolved together — ‘co-evolved’ — in step with each other and out of step with other fig and wasp species. We have seen the advantage of this from the figs’ point of view. Their private species of pollinating wasp is the ultimate magic bullet. By cultivating one, and only one, species of wasp, they target their pollen strictly to female figs of their own species and no other. They do not waste pollen the way they would if they had to share the same species of wasp, one species that promiscuously visits all fig species. Whether such strict loyalty to one fig species also benefits the wasps is less clear, but they probably have no choice. For reasons that we need not go into, species occasionally evolve away from one another, splitting into two species. In the case of fig trees, when they diverge in evolutionary time they may well change the chemical passwords by which wasps recognize figs, and perhaps also such lock-and-key details as the depth of their tiny flowers. Wasp species are forced to follow suit. For instance, gradually deepening flowers on the fig (lock) side of the coevolution impose gradually lengthening ovipositors on the wasp (key) side of the co-evolution.
Now comes a peculiar problem recognized by Grafen and Godfray. Let's expand the lock-and-key analogy. Fig species evolve away from each other by changing their locks, and wasps follow suit with their keys. Something like this must have gone on when ancestral orchids {324} diverged into bee orchids, fly orchids and wasp orchids. But there it is easy to see how the coevolution took place. Figs raise a very special and very tantalizing problem, and it is the last problem I shall tackle in this book. If the story went according to the usual co-evolutionary plan, we should expect to see something like the following. Genes for deeper flowers, say, would be selected among the female figs. This would set up a selection pressure in favour of longer ovipositors among wasps. But because of the odd circumstances of these figs, this normal story of co-evolution can't work. The only female flowers that pass on genes are the true female ones in female figs, not the pseudo-female florets in male figs; while the only female wasps that pass on genes are the ones that lay eggs in pseudo-female flowers, not the ones that lay eggs in real female flowers. So those individual wasps that happen to have long ovipositors and succeed in reaching the bottom of the long female flowers wont pass on the genes for long ovipositors. Those individual wasps whose long ovipositors reach the bottom of the pseudo-female flowers will pass their own genes on. But here the genes for making long flowers won't be passed on. We have a riddle.
Once again, the answer seems to lie in vicarious selection — accurate simulators for pilots. Male figs ‘want’ the wasps that they export to be good at pollinating true female flowers. Therefore, in our hypothetical example, they would want them to have long ovipositors. The best way for a male fig to ensure this is to allow only mothers with long ovipositors to lay eggs in their pseudo-female flowers. Expressing the idea in terms of this particular example runs the risk of making it sound too purposeful, as though the male figs ‘know’ that female flowers are deep. Natural selection would do it automatically by favouring those male figs whose pseudo-female flowers resembled true female flowers in all respects, including depth.
Figs and fig wasps occupy the high ground of evolutionary achievement: a spectacular pinnacle of Mount Improbable. Their relationship is almost ludicrously tortuous and subtle. It cries out for interpretation in the language of deliberate, conscious, Machiavellian calculation. Yet it is achieved in the complete absence of any kind of deliberation, without brain power or intelligence of any kind. The point is rubbed home {325} for us by the very fact that the players are a tiny wasp with a very tiny brain on the one hand, and a tree with no brain at all on the other. It is all the product of an unconscious Darwinian fine-tuning, whose intricate perfection we should not believe if it were not before our eyes. There is a form of calculation going on, or rather millions of parallel calculations, of costs and benefits. The calculations are of a complexity to tax our largest computers. Yet the ‘computer’ that is performing them is not made of electronic components, not even made of neural components. It is not located in a particular place in space at all. It is an automatic, distributed computer whose data bits are stored in DNA code, spread over millions of individual bodies, shuttling from body to body, via the processes of reproduction.
The famous Oxford physiologist Sir Charles Sherrington compared the brain to an enchanted loom in a famous passage:
It is as if the Milky Way entered upon some cosmic dance. Swiftly the brain becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of subpatterns.
It was the rise of nervous systems and brains that brought designed objects into the world. Nervous systems themselves, and all designoid objects, are the products of an older and a slower cosmic dance. Sherrington's vision helped him to become one of the leading investigators of the nervous system in the first part of this century. We may profit by borrowing a parallel vision. Evolution is an enchanted loom of shuttling DNA codes, whose evanescent patterns, as they dance their partners through geological deep time, weave a massive database of ancestral wisdom, a digitally coded description of ancestral worlds and what it took to survive in them.
But that is a train of thought that must wait for another book. The main lesson of this book is that the evolutionary high ground cannot be approached hastily. Even the most difficult problems can be solved, and even the most precipitous heights can be scaled, if only a slow, gradual, step-by-step pathway can be found. Mount Improbable cannot be assaulted. Gradually, if not always slowly, it must be climbed. {326}
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BIBLIOGRAPHY
BOOKS REFERRED TO AND SUGGESTIONS FOR FURTHER READING
Adams, D. (1989) The More than Complete Hitchhiker's Guide. New York: Wings Books.
Attenborough, D. (1979) Life on Earth. London: Collins.
Attenborough, D. (1984) The Living Planet. London: Collins/BBC Books.
Attenborough, D. (1995) The Private Life of Plants. London: BBC Books.
Basalla, G. (1988) The Evolution of Technology. Cambridge: Cambridge University Press.
Berry, R. J., and Hallam, A. (Eds.) (1986) Collins Encyclopedia of Animal Evolution. London: Collins.
Bonner, J. T. (1988) The Evolution of Complexity. Princeton, NJ: Princeton University Press.
Bristowe, W. S. (1958) The World of Spiders. London: Collins.
Brusca, R. C, and Brusca, G. J. (1990) Invertebrates. Sunderland, Mass.: Sinauer.
Carroll, S. B. (1995) ‘Homeotic genes and the evolution of arthropods and chordates’. Nature, 376, 479–85.
Coveney, P., and Highfield, R. (1995) Frontiers of Complexity. London: Faber and Faber.
Cringely, R. X. (1992) Accidental Empires. London: Viking.
Cronin, H. (1991) The Ant and the Peacock. Cambridge: Cambridge University Press. {327}
Dance, S. P. (1992) Sheik London: Dorling Kindersley.
Darwin, C. (1859) The Origin of Species. Harmondsworth (1968): Penguin.
Darwin, C. (1882) The Various Contrivances by Which Orchids are Fertilised by Insects. London: John Murray.
Dawkins, R. (1982) The Extended Phenotype. Oxford: W. H. Freeman.
Dawkins, R. (1986) The Blind Watchmaker. Harlow: Longman.
Dawkins, R. (1989) ‘The evolution of evolvability’. In Artificial Life. (Ed. C. Langton.) Santa Fe: Addison-Wesley.
Dawkins, R. (1989) The Selfish Gene. (2nd edn) Oxford: Oxford University Press.
Dawkins, R. (1995) River Out of Eden. London: Weidenfeld and Nicolson.
Dennett, D. C. (1995) Darwin's Dangerous Idea. New York: Simon and Schuster.
&n
bsp; Douglas-Hamilton, I. and O. (1992) Battle for the Elephants. London: Doubleday.
Drexler, K. E. (1986) Engines of Creation. New York: Anchor Press/Doubleday.
Eberhard, W. G. (1985) Sexual Selection and Animal Genitalia. Cambridge, Mass.: Harvard University Press.
Eldredge, N. (1995) Reinventing Darwin: The great debate at the high table of evolutionary theory. New York: John Wiley.
Fisher, R. A. (1958) The Genetical Theory of Natural Selection. New York: Dover.
Ford, E. B. (1975) Ecological Genetics. London: Chapman and Hall.
Frisch, K. v. (1975) Animal Architecture. London: Butterworth.
Fuchs, P., and Krink, T. (1994) ‘Modellierung als Mittel zur Analyse raumlichen Orientierungsverhaltens’. Diplomarbeit, Universitat Hamburg.
Goodwin, B. (1994) How the Leopard Changed its Spots. London: Weidenfeld and Nicolson.
Gould, J. L., and Gould, C. G. (1988) The Honey Bee. New York: Scientific American Library.
Gould, S. J. (1983) Hen's Teeth and Horse's Toes. New York: W. W. Norton.
Grafen, A., and Godfray, H. C. J. (1991) ‘Vicarious selection explains some paradoxes in dioecious fig-pollinator systems’. Proceedings of the Royal Society of London, B., 245, 73–6.
Gribbin, J., and Gribbin, M. (1993) Being Human. London: J. M. Dent. Haeckel, E. (1974) Art Forms in Nature. New York: Dover. {328}
Haldane, J. B. S. (1985) On Being the Right Size. (Ed. J. Maynard Smith.) Oxford: Oxford University Press.
Haider, G., Callaerts, P., and Gehring, W. J. (1995) ‘Induction of ectopic eyes by targeted expression of the eyeless gene in Drosophila. Science, 267, 1788–92.
Hamilton, W. D. (1996) Narrow Roads of Gene Land: The collected papers of W. D. Hamilton, Vol. I. Evolution of Social Behaviour. Oxford: W. H. Freeman/Spektrum.
Hansell, M. H. (1984) Animal Architecture and Building Behaviour. London: Longman.
Hayes, B. (1995) ‘Space-time on a seashell’. American Scientist, 83, 214–18.
Heinrich, B. (1979) Bumblebee Economics. Cambridge, Mass.: Harvard University Press.
Holldobler, B., and Wilson, E. O. (1990) The Ants. Berlin: Springer-Verlag.
Hoyle, F. (1981) Evolution From Space. London: J. M. Dent.
Janzen, D. (1979) ‘How to be a fig’. Annual Review of Ecology and Systematics, 10, 13–51.
Kauffman, S. (1995) At Home in the Universe. Harmondsworth: Viking.
Kettlewell, H. B. D. (1973) The Evolution of Melanism. Oxford: Oxford University Press.
Kingdon, J. (1993) Self-made Man and His Undoing. London: Simon and Schuster.
Kingsolver, J. G., and Koehl, M. A. R. (1985) Aerodynamics, thermoregulation, and the evolution of insect wings: differential scaling and evolutionary change’. Evolution, 39, 488–504.
Land, M. F. (1980) ‘Optics and vision in invertebrates’. In Handbook of Sensory Physiology. (Ed. H. Autrum.) VII/6B, 471–592. Berlin: Springer-Verlag.
Langton, C. G. (Ed.) (1989) Artificial Life. New York: Addison-Wesley.
Lawrence, P. A. (1992) The Making of a Fly. London: Blackwell Scientific Publications.
Leakey, R. (1994) The Origin of Humankind. London: Weidenfeld and Nicolson.
Lundell, A. (1989) Virus! The secret world of computer invaders that breed and destroy. Chicago: Contemporary Books.
Macdonald, D. (Ed.) (1984) The Encyclopedia of Mammals. (2 vols.) London: Allen and Unwin.
Margulis, L. (1981) Symbiosis in Cell Evolution. San Francisco: W. H. Freeman.
Maynard Smith, J. (1988) Did Darwin Get it Right? Harmondsworth: Penguin Books. {329}
Maynard Smith, J. (1993) The Theory of Evolution. Cambridge: Cambridge University Press.
Maynard Smith, J., and Szathnvry, E. (1995) The Major Transitions in Evolution. Oxford: Freeman/Spektrum.
Meeuse, B., and Morris, S. (1984) The Sex Life of Plants. London: Faber and Faber.
Meinhardt, H. (1995) The Algorithmic Beauty of Sea Shells. Berlin: Springer-Verlag.
Moore, R. C, Lalicker, C. G., and Fischer, A. G. (1952) Invertebrate Fossils. New York: McGrawHill.
Nesse, R., and Williams, G. C. (1995) Evolution and Healing: The New Science of Darwinian Medicine. London: Weidenfeld and Nicolson. Also published as Why We Get Sick by Random House, New York.
Nilsson, D.-E. (1989) ‘Vision, optics and evolution’. Bioscience, 39, 298–307.
Nilsson, D.-E. (1989) ‘Optics and evolution of the compound eye’. In Facets of Vision. (Eds. D. G. Stavenga and R. C. Hardie.) Berlin: Springer-Verlag.
Nilsson, D.-E., and Pelger, S. (1994) A pessimistic estimate of the time required for an eye to evolve’. Proceedings of the Royal Society of London, B, 256, 53–8.
Orgel, L. E. (1973) The Origins of Life. London: Chapman and Hall.
Pennycuick, C. J. (1972) Animal Flight. London: Edward Arnold.
Pennycuick, C. J. (1992) Newton Rules Biology. Oxford: Oxford University Press.
Pinker, S. (1994) The Language Instinct. Harmondsworth: Viking.
Provine, W. B. (1986) Sewall Wright and Evolutionary Biology. Chicago: Chicago University Press.
Raff, R. A., and Kaufman, T. C. (1983) Embryos, Genes and Evolution. New York: Macmillan.
Raup, D. M. (1966) ‘Geometric analysis of shell coiling: general problems’. Journal of Paleontology, 40, 1178–90.
Raup, D. M. (1967) ‘Geometric analysis of shell coiling: coiling in ammonoids’. Journal of Paleontology, 41, 43–65.
Ridley, Mark (1993) Evolution. Oxford: Blackwell Scientific Publications.
Ridley, Matt (1993) The Red Queen: Sex and the evolution of human nature. Harmondsworth: Viking.
Robinson, M. H. (1991) ‘Niko Tinbergen, comparative studies and evolution’. In The Tinbergen Legacy. (Eds. M. S. Dawkins, T. R. Halliday, and R. Dawkins.) London: Chapman and Hall. {330}
Ruse, M. (1982) Darwinism Defended. Reading, Mass.: Addison-Wesley.
Sagan, C, and Druyan, A. (1992) Shadows of Forgotten Ancestors. New York: Random House.
Salvini-Plawen, L. v. and Mayr, E. (1977) ‘On the evolution of photoreceptors and eyes’. In Evolutionary Biology. (Eds. M. K. Hecht, W. C. Steere, and B. Wallace.) 10, 207–63. New York: Plenum.
Terzopoulos, D., Tu, X., and Grzeszczuk, R. (1995) Artificial fishes: autonomous locomotion, perception, behavior, and learning in a simulated physical world’. Artificial Life, 1, 327–51.
Thomas, K. (1983) Man and the Natural World: Changing Attitudes in England 1500–1800. Harmondsworth: Penguin Books.
Thompson, D.A. (1942) On Growth and Form. Cambridge: Cambridge University Press.
Trivers, R. L. (1985) Social Evolution. Menlo Park: Benjamin/Cummings.
Vermeij, G. J. (1993) A Natural History of Shells. Princeton, NJ: Princeton University Press.
Vollrath, F. (1988) ‘Untangling the spider's web’. Trends in Ecology and Evolution, 3, 331–5.
Vollrath, F. (1992) ‘Analysis and interpretation of orb spider exploration and web-building behavior’. Advances in the Study of Behavior, 21, 147–99.
Vollrath, F. (1992) ‘Spider webs and silks’. Scientific American, 266, 70–76.
Watson, J. D., Hopkins, N. H., Roberts, J. W, Steitz, J. A., and Weiner, A. M. (1987) Molecular Biology of the Gene (4th edn). Menlo Park: Benjamin/Cummings.
Weiner, J. (1994) The Beak of the Finch. London: Jonathan Cape.
Williams, G. C. (1992) Natural Selection: Domains, Levels and Challenges. Oxford: Oxford University Press.
Wilson, E. O. (1971) The Insect Societies. Cambridge, Mass.: The Belknap Press of Harvard University Press.
Wolpert, L. (1991) The Triumph of the Embryo. Oxford: Oxford University Press.
Wright, S. (1932) ‘The roles of mutation, inbreeding, crossbreeding and selection in evolution’. Proceedings 6th International Congress of Genetics, 1, 356–66. {331}
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Index
acacia trees, and ants, 266
accident, and design, 6
A
dams, Douglas, 257–8
aeroplane wings, 127
Agaonidac, 300
altruism, male fig wasps, 308–9
Ampelisca, 183 (fig.)
animal(s)
artefacts, 18
big, as scaled up small, 111
land, return to water, 130–3
flying, problems of size, 112
small, ability to float, 112
‘statues’, 9
ant(s)
and acacia trees, 266
accommodation for, 265 (fig.)
‘gardens’, 264 ant-loving plants, 265
ant-mimicking beetle, 7–8 (fig.)
segmentation, 241–2
Araneus diadematus, web building, 43–4
artefacts, animal, 18
arthromorphs
artificial selection, 249
zoo, 250 (fig.)
computer, 243–4
genetic effects, 246 (fig.)
segments, 245 (fig.)
arthropods
bodies, 243
kaleidoscopic genes, 254
repeated segments, 241 (fig.)
variation of segments, 254 (fig.)
artificial life, journal, 69
Artificial Natural Selection, 72
artificial selection
animals, 29 (fig.)
arthromorphs, 249
computer biomorphs, 30–4
and natural selection, 34–5
plants, 27 (fig.)
shells, 215 (fig.)
Asimov, Isaac, 78
asymmetry, possible evolution, 229
bacteria, as example of TRIP robots, 286–7
banana, usefulness of, 258
Batbylychnops exilis, eye evolution, 196 (fig.)
Bauplan, 228
bees
mason, pot nests, 16
nectar, 258–9
ultraviolet vision, 259–60