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Climbing Mount Improbable

Page 33

by Richard Dawkins


  pupils

  changing size of, 166

  evolution of, 170

  variable shape, 169 (fig.), 168

  Quiring, Rebecca, 193

  Radiolaria, 235–6 (fig.)

  raindrops, and photons, 144

  Raup, David, 201–3, 206–7, 211

  refraction, principle of, 155 (fig.)

  refractive index, 155

  relaxation, in evolution, 135–6

  reproduction

  different from heredity, 88

  Muller's Ratchet, 85

  sexual, rearranging genes, 83–4

  retina

  as biological photocell, 145 (fig.)

  independent evolution of, 170–1

  rods and cones, 172

  Robinson, Michael, 53

  robot(s)

  definition, 281

  horse, as vehicle for DNA, 290 (fig.)

  industrial, 278–9

  movement of, 279

  self-duplicating, 281

  TRIP, 280–1

  rod, retinal, 145 (fig.), 172

  saltations, genetic defects, 97

  scallop, mirror solutions to image-forming, 176–7

  Scyllarus, homeotic mutation, 252 (fig.)

  sea-dragon, leafy, 9–10

  sea-cows, 130, 131 (fig.) {338}

  seeds, with wings, 274 (fig.)

  segmentation, 240–55

  selection

  artificial, see artificial selection

  natural, see natural selection

  pressure, 198–9

  vicarious, 324

  sex

  evolution of, 85

  Muller's Ratchet, 85

  recombination of DNA, 90

  and rearrangement of genes, 84

  reproduction on NetSpinner, 63

  spiders, 49

  shells

  computer simulation, 201, 206 (fig.), 212

  artificial selection, 215 (fig.)

  resemblance to real shells, 216–7 (fig.)

  X-ray view, 209 (fig.)

  flare, verm and spire, 204, 207 (fig.)

  shapes, 213 (fig.)

  theoretical, 218 (fig.)

  tube, 204–5

  X-ray view, 209 (fig.)

  Sherrington, Sir Charles, 326

  silk, spider, 39, 68

  and sex, 49

  stickiness, 41

  see also spiders, webs

  skate, and flounder, 134 (fig.)

  solar panels, and insect wings, 114

  soup, primeval, 282

  species, classification of, 106

  spherical aberration, 173

  spiders

  bolas, 55–7

  female, larger than males, 47

  hunting, 51

  jumping, 173

  male: dangers in mating, 48

  mating thread, 49 (fig.)

  tying down female, 50 (fig.)

  mating, 49, 53, 63

  mating thread, 49 (fig.)

  poisoning prey, 52

  predators, 47

  problems for, 43–52

  solution to ‘own goal’ hazard, 44

  webs, 4, 38–72

  building, 43–8

  computer simulation, 57–69

  evolution on NetSpinner, 62 (fig.)

  economy, 41

  efficiency of, 38

  fine tuning, 49–50

  laying thread, 45

  optimal tension, 54

  problems laying thread, 46–7

  radiating spokes, 46

  simulation of natural selection, 37

  stickiness, 42 (fig.)

  spine, flexing, mammals and fish, 123

  spire (shells), 203–6 (fig.)

  spirula, odd shell, 219

  spring hare, 124 (fig.)

  sprung trap, spider techniques, 54

  squids

  flying, 121

  independently evolved eyes, 145

  squirrel, flying, evolution of, 118

  stable balance theory

  evidence for, 314

  two kinds of males, 313–4

  statues

  animal, 9

  designoid, 10

  stones, no offspring from, 26

  stress

  increased mutation rates, 86

  and mutation, 83

  mutation penalized by natural selection, 86

  sun, and remote guidance technology, 138

  superposition, 188, 189 (fig.)

  survival, animal, contributions to, 36

  symmetry, 225–40

  computer biomorphs, 225–7 (fig.)

  echinoderms, 238 (fig.)

  five-way, 239

  four-way, 231 (fig.)

  ‘Isle of Man’, 232 (fig.)

  left-right, 230

  radial, 232

  six-way, 236, 237 (fig.)

  tailorbird, nest, 17 (fig.)

  telescope, Keplerian, 187

  tenrec, 19, 20 (fig.)

  termites

  compass, 17

  mimicry, 8–9, 8 (fig.)

  Terzopoulos, Demetri, 69–71

  thermals, 128

  Thomas, Keith, 256

  Thompson, D'Arcy Wentworth, 201

  Thomson, William, 76

  ‘tortoise’ robot (Machina speculatrix), 280

  ‘Total Replication of Instructions’ Program (TRIP), 276, 286

  trachymedusae, six-way symmetry, 237

  transparency, principle of refraction, 155

  traps, for insects, 14 {339}

  trees

  acacia, and ants, 266

  and evolution of flight in vertebrates, 115

  fig, and fig wasps, 262

  real and computerized, 31 (fig.)

  Trivers, Robert, 24

  trunk, elephant, 4, 92, 94

  Tu, Xiaoyuan, 69–71

  tube (shells) 204–5, 206 (fig.)

  generated by Blind Snailmaker, 212

  tusks, elephant, fossilization of, 94

  ultraviolet light, and bee vision, 259

  University of California, 113

  variation, and natural selection, 165

  Venus's fly trap, 14

  verm (shells), 204–6 (fig.), 207 (fig.)

  Vermeij, Geerat, 216

  vertebrates

  flight, 115

  see also birds

  gliding, 119 (fig.)

  and squids, independently evolved eyes, 145

  viruses

  biological purpose of, 268–72

  computer, 269

  DNA, hosts, 274

  vitreous mass, 159–61

  Vollrath, Fritz, 41, 56

  volvox, representing early life, 287

  von Frisch, Karl 17

  von Neumann, John, 281

  vultures, use of thermals, 128

  Waldorf, Uwe, 193

  Walter, W. Grey, 280

  wasps

  designoid pots, 15–6

  and figs, co-evolution, 262, 301, 307–9, 320, 324–5

  freeloader species, 312

  parasitic, 311 (fig.)

  potter, 16

  prey to spiders, 54

  selfishness, 320

  winged male, 315–6

  wingless male, 315–6

  water

  living in, 130

  return to, by large mammals, 130

  Watson, J. D., 271

  weaverbird, nest, 17 (fig.)

  webs, spider, see spiders, webs whales, 130, 131 (fig.)

  dry-land history, 130

  whippet, artificial selection, 29 (fig.)

  Wickramasinghe, Chandra, 75

  Williams, George, 293

  wings, 4

  aerodynamic efficiency, 113

  birds and aeroplanes, 127

  fig wasps, 301

  insects, 241

  on seeds, 274 (fig.)

  spread of genetic instructions, 273

  wolf, artificial selection, 29 (fig.)

  worms, primitive compound eyes, 184 (fig.)

  Wri
ght, Sewall, 135

  Zschokke, Sam, 58 {340}

  * * *

  * I shall be using Latin names, and I hope I shall be forgiven a schoolmasterly footnote on the conventions governing them because surprising numbers of educated people (perhaps the same people as wince-makingly refer to Darwin's masterwork as Origin of the Species) get them wrong. Latin names have two parts: a generic name (e.g. Homo is a genus) followed by a specific name (e.g. sapiens is the only surviving species of Homo), both written in italics or underlined. Names of larger units are not italicized. The genus Homo belongs to the family Hominidae. Generic names are unique: there is only one genus Homo, only one genus Vespa. Species often share a name with species in other genera, but there is no confusion because of the uniqueness of the generic name: Vespa vulgaris is a wasp, in no danger of being mistaken for Octopus vulgaris. The generic name always begins with a capital letter and the specific name never does (nowadays, although the original convention was that it could if derived from a proper name. Even Darwinii would nowadays be written darwinii). If ever you see (and you often will) Homo Sapiens or homo sapiens it is always a mistake. Note, by the way, that the word ‘species’ is both singular and plural. The plural of genus is genera.

  • Judith Flanders has called my attention to the following amusingly relevant story in Robert X. Cringely's book, Accidental Empires. The story concerns the Apple III, a desktop computer of the generation between the famous Apple II and the even more famous Macintosh, launched in 1980: ‘...the automated machinery that inserted dozens of computer chips on the main circuit board didn't push them into their sockets firmly enough. Apple's answer was to tell 90,000 customers to pick up their Apple III carefully, hold it twelve to eighteen inches above a level surface, and then drop it, hoping that the resulting crash would reseat all the chips.’

  * After writing this I was informed by a correspondent, Howard Kleyn, formerly of the Cable and Wireless Company, that humans do, as a matter of fact, make something equivalent to a graded index lens. It is actually a graded index optical fibre. By his description, it works like this. You start with a hollow tube of good glass, about a metre long and a few centimetres in diameter, which you heat up. You then puff into the tube finely powdered glass. The powdered glass melts and fuses with the lining of the tube, thereby thickening the lining while narrowing the bore of the tube. Now comes the cunning part. As this procedure progresses, the powder that is puffed in is of gradually changing quality: specifically, it has been ground from glass of progressively increasing refractive index. By the time the hoEow bore has narrowed to nothing, the tube has become a rod made of highly refracting glass at its central core with graduafly decreasing refractive index as you move towards its outer layers. The rod is then heated again, and drawn out into a fine filament. This filament retains the same graded refractive index, from core to periphery, in miniature, as the rod from which it was drawn. It is technically a graded index lens, albeit a very thin, long one. Its lens property is used not for focusing an image but for improving its quality as a light guide which does not allow its beam of light to disperse. Several of these filaments would normally be used to manufacture a multi-stranded optical fibre cable.

  * These engaging little animals, whose habit of cocking their heads to look at you gives them an almost human charm, stalk their prey like a cat and then jump on to it explosively and without warning. Explosive it more or less literally is, by the way, for they jump by hydraulically pumping fluid into all eight legs simultaneously — a little like the way we (those of us who have them) erect our penises, but their ‘leg erections’ are sudden rather than gradual.

 

 

 


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