Chapter Only A Theory

Imagine that you are a teacher of Roman history and the Latin language, anxious to impart your enthusiasm for the ancient world - for the elegiacs of Ovid and the odes of Horace, the sinewy economy of Latin grammar as exhibited in the oratory of Cicero, the strategic niceties of the Punic Wars, the generalship of Julius Caesar and the voluptuous excesses of the later emperors. That's a big undertaking and it takes time, concentration, dedication. Yet you find your precious time continually...

Chapter Silence And Slow Time

If the history-deniers who doubt the fact of evolution are ignorant of biology, those who think the world began less than ten thousand years ago are worse than ignorant, they are deluded to the point of perversity. They are denying not only the facts of biology but those of physics, geology, cosmology, archaeology, history and chemistry as well. This chapter is about how we know the ages of rocks and the fossils embedded in them. It presents the evidence that the timescale on which life has...

No Borrowing

To emphasize how odd the idea of a creator sticking rigidly to 'themes' is, reflect that any sensible human designer is quite happy to borrow an idea from one of his inventions, if it would benefit another. Maybe there is a 'theme' of aircraft design, which is separate from the 'theme' of train design. But a component of a plane, say an improved design for the reading lights above the seats, might as well be borrowed for use in trains. Why should it not, if it serves the same purpose in both...

Chapter Before Our Very Eyes

P. 112 The graph above shows data from the Uganda Game Department Brooks and Buss (1962). p. 113 In that year experimenters transported five pairs of Podarcis sicula from Pod Kopiste Research on the lizards of Pod Mrcaru from Herrel et al. (2008) and Herrel et al. (2004). p. 117 All this has been achieved with the bacterium Escherichia coli Lenski E. coli research from Lenski and Travisano (1994). In addition, Lenski group publications are collected at p. 131 the celebrated scientific blogwit...

Just Go And Look

So, we have fine fossil documentation of gradual change, all the way from Lucy, the 'upright-walking chimp' of three million years ago, to ourselves today. How do history-deniers cope with this evidence Some by literal denial. I encountered this in an interview I did for the Channel Four television documentary The Genius ofCharles Darwin in 2008. I was interviewing Wendy Wright, President of 'Concerned Women for America'. Her opinion that 'The morning-after pill is a pedophile's best friend'...

Having Been Originally Breathed

I have lost count of the irate letters I have received from readers of a previous book, taking me to task for, as the writers think, deliberately omitting the vital phrase, 'by the Creator' after 'breathed' Am I not wantonly distorting Darwin's intention These zealous correspondents forget that Darwin's great book went through six editions. In the first edition, the sentence is as I have written it here. Presumably bowing to pressure from the religious lobby, Darwin inserted 'by the Creator' in...

The Solar Economy

The natural economy is solar-powered. Photons from the sun rain down upon the entire daytime surface of the planet. Many photons do nothing more useful than heat up a rock or a sandy beach. A few find their way into an eye - yours, or mine, or the compound eye of a shrimp or the parabolic reflector eye of a scallop. Some may happen to fall on a solar panel - either a man-made one like those that, in a fit of green zeal, I have just installed on my roof to heat the bathwater, or a green leaf,...

Once Proud Wings

The bodies of whales and sirenians abound in historical relics that we notice because they live in a very different environment from their land-dwelling ancestors. A similar principle applies to birds that have lost the habit and equipment of flight. Not all birds fly, but all birds carry at least relics of the apparatus of flight. Ostriches and emus are fast runners that never fly, but they have stubs of wings as a legacy from remote flying ancestors. Ostrich wing stubs, moreover, have not...

Running To Stay In The Same Place

The five fastest runners among mammal species are the cheetah, the pronghorn (often called 'antelope' in America although it is not closely related to the 'true' antelopes of Africa), the gnu (or wildebeest, a true antelope although it doesn't look much like the others), the lion, and the Thomson's gazelle (another true antelope, which really does look like a standard antelope, a small one). Note that these top-ranked runners are a mixture of hunted and hunters, and my point is that this is no...

Im Still Mischievously Hoping

Molecular evidence (which I shall come on to in Chapter 10) shows that the common ancestor we share with chimpanzees lived about six million years ago or a bit earlier, so let's split the difference and look at some three-million-year-old fossils. The most famous fossil of this vintage is 'Lucy', classified by her discoverer in Ethiopia, Donald Johanson, as Australopithecus afarensis. Unfortunately we have only fragments of Lucy's cranium, but her lower jaw is unusually well preserved. She was...

Parasitic fly from the Phoridae family

Probably for similar reasons, ants' nests, and termites' nests, are home to a horde of wingless hangers-on of many different types, feeding on the rich pickings swept in by the ever-rustling streams of returning foragers. And wings are just as much of a hindrance to them as they are to the ants themselves. Who would ever believe that the monstrosity on the right is a fly Yet we know from a careful and detailed study of its anatomy that not only is it a fly, this parasite of termite nests...

A frame

Actually, these two shortcomings kind of cancel each other out. The sheets of tissue that fold, invaginate and turn inside out in a developing embryo do indeed grow, and it is that very growth that provides part of the motive force which, in origami, is supplied by the human hand. If you wanted to make an origami model with a sheet of living tissue instead of dead paper, there is at least a sporting chance that, if the sheet were to grow in just the right way, not uniformly but faster in some...

Fortyfive Thousand Generations Of Evolution In The

The average generation turnover of those lizards is about two years, so the evolutionary change observed on Pod Mrcaru represents only about eighteen or nineteen generations. Just think what you might see in three or four decades if you followed the evolution of bacteria, whose generations are measured in hours or even minutes, rather than years Bacteria offer another priceless gift to the evolutionist. In some cases you can freeze them for an indefinite length of time and then bring them back...

Hodgkins

The largest-scale attempt in that direction so far has been made by a group associated with David Hillis, brother of Danny Hillis who pioneered one of the first supercomputers. The Hillis plot makes the tree diagram more compact by wrapping it around in a circle. You can't see the gap, where the two ends almost meet, but it lies between the 'bacteria' and the 'archaea'. To see how the circular plot works, look at the greatly stripped-down version tattooed on the back of Dr Clare D'Alberto of...

Brains of human top dolphin middle brown trout bottom not to scale

Warm-blooded is what we call mammals and birds, but really what they have is the ability to keep their temperature constant, regardless of the outside temperature. This is a good idea, because the chemical reactions in a cell can then all be optimized to work best at a particular temperature. 'Cold-blooded' animals are not necessarily cold. A lizard has warmer blood than a mammal if both happen to be out in the midday sun in the Sahara desert. A lizard has colder blood than a mammal if they are...

Formation of neural tube in Osters model

My purpose in expounding the Oster models has been to show the general kind of principle by which single cells can interact with each other to build a body, without any blueprint representing the whole body. Origami-like folding, Oster-style invagination and pinching off these are just some of the simplest tricks for building embryos. Other more elaborate ones come into play later in embryonic development. For example, ingenious experiments have shown that nerve cells, when they grow out from...

Must Go Down To The Sea Again

Basilosaur

The move from water to land launched a major redesign of every aspect of life, from breathing to reproduction it was a great trek through biological space. Nevertheless, with what seems almost wanton perversity, a good number of thoroughgoing land animals later turned around, abandoned their hard-earned terrestrial retooling, and trooped back into the water again. Seals and sea lions have only gone part-way back. They show us what the intermediates might have been like, on the way to extreme...

Ill Believe In Evolution When A Monkey Gives Birth To A Human Baby

Once again, humans are not descended from monkeys. We share a common ancestor with monkeys. As it happens, the common ancestor would have looked a lot more like a monkey than a man, and we would indeed probably have called it a monkey if we had met it, some 25 million years ago. But even though humans evolved from an ancestor that we could sensibly call a monkey, no animal gives birth to an instant new species, or at least not one as different from itself as a man is from a monkey, or even from...

Sahelanthropus

Palaeoanthropology, more than other fields of science, is notoriously plagued - or is it enlivened - by rivalries. We have to admit that the fossil record connecting the upright-walking ape Australopithecus to the presumably quadrupedal ancestor that we share with chimpanzees is still poor. We don't know how our ancestors rose on to their hind legs. We need more fossils. But let's at least rejoice in the good fossil record that we - unlike Darwin - can enjoy, showing us the evolutionary...

Chapter The Primrose Path To Macroevolution

P. 50 'I have carefully measured the proboscis of a specimen' Wallace 1871 . p. 57 'The resemblance of Dorippe to an angry Japanese warrior' Julian Huxley, 'Evolution's copycats', Life, 30 June 1952 also in Huxley 1957 as 'Life's improbable likenesses'. p. 58 I even found a website where you can vote Samurai crab poll from http www.pollsb. p. 58 as one authoritative sceptic has pointed out Martin 1993 . p. 65 'My dear Darwin' Marchant 1916 , 170. p. 67 agronomists at the Illinois Experimental...

TABLE Responses to the proposition that human beings as we know them today developed from earlier species of animals

As a biological educator, I find myself pathetically consoled by another result from the Eurobarometer survey revealing the large number 19 in Britain who believe it takes one month for the Earth to go around the sun. The figure is more than 20 for Ireland, Austria, Spain and Denmark. What, I wonder, do they think a year is Why do the seasons come and go with such regularity Are they not even curious about the reasons for such a salient feature of their world These remarkable figures shouldn't...

Bone To His Bone

Whole Form Pterodactyl Bones

What a piece of work is the mammalian skeleton. I don't mean it is beautiful in itself, although I think it is. I mean the fact that we can talk about 'the' mammalian skeleton at all the fact that such a complicatedly interlocking thing is so gloriously different across the mammals, in all its parts, while simultaneously being so obviously the same thing throughout the mammals. Our own skeleton is familiar enough to need no picture, but look at this skeleton of a bat. Isn't it fascinating how...

Microfilaments inside Osters model cell

So, we have our model of a single cell a greatly simplified model consisting of a two-dimensional outline in which are strung six elastic springs, one of which has the special property of responding to an externally imposed stretch by actively contracting. That is stage one of the modelling process. In stage two, Oster and his colleagues cloned up a few dozen of their model cells and arranged them in a circle, like a two-dimensional blastula. Then they took one cell and tweaked its contractile...

The Molecular Clock

Now, while we are talking molecules, we have some unfinished business left over from the chapter on evolutionary clocks. There, we looked at tree rings, and at various kinds of radioactive clocks, but we deferred consideration of the so-called molecular clock until we had learned about some other aspects of molecular genetics. The time has now come. Think of this section as an appendix to the chapter on clocks. The molecular clock assumes that evolution is true, and that it proceeds at a...

The Dead Hand Of Plato

For Plato, the 'reality' that we think we see is just shadows cast on the wall of our cave by the flickering light of the camp fire. Like other classical Greek thinkers, Plato was at heart a geometer. Every triangle drawn in the sand is but an imperfect shadow of the true essence of triangle. The lines of the essential triangle are pure Euclidean lines with length but no breadth, lines defined as infinitely narrow and as never meeting when parallel. The angles of the essential triangle really...

Heikea japnica crab

This theory, that generations of superstitious fishermen threw back into the sea crabs that resembled human faces, received new legs in 1980 when Carl Sagan discussed it in his wonderful Cosmos. In his words, Suppose that, by chance, among the distant ancestors of this crab, one arose that resembled, even slightly, a human face. Even before the battle of Danno-ura, fishermen may have been reluctant to eat such a crab. In throwing it back, they set in motion an evolutionary process . . . As the...

From The War Of Nature From Famine And Death

Clear-headed as ever, Darwin recognized the moral paradox at the heart of his great theory. He didn't mince words - but he offered the mitigating reflection that nature has no evil intentions. Things simply follow from 'laws acting all around us', to quote an earlier sentence from the same paragraph. He had said something similar at the end of Chapter 7 of The Origin it may not be a logical deduction, but to my imagination it is far more satisfactory to look at such instincts as the young...

Lenski experiment bacterial body size in one tribe

You can see that most of the increase in body size occurred in the first 2,000 or so generations. The next interesting question is this. Given that all twelve tribes increased in body size over evolutionary time, did they all increase in the same way, by the same genetic route No, they didn't, and that's the second interesting result. The graph at the top of page 123 is for one of the twelve tribes. Now look at the equivalent hyperbolic best fits for all twelve graph at the foot of page 123 ....

Chapter Arms Races And Evolutionary Theodicy

P. 380 The five fastest runners among mammal species List from http www.petsdo.com p. 382 My colleague John Krebs and I published a paper on the subject in 1979 Dawkins and Krebs 1979 . p. 382 'Before asserting that the deceptive appearance' Cott 1940 , 158-9. pp. 383-4 And there are even, though it may seem surprising, arms races between males and females within a species, and between parents and offspring See Dawkins 2006 , chs 8 and 9, 'Battle of the generations' and 'Battle of the sexes'....

Domestication

This chapter is mostly about selection by eyes, but other senses can do the same thing. Fanciers have bred canaries for their songs, as well as for their appearance. The wild canary is a yellowish brown finch, not spectacular to look at. Human selective breeders have taken the palette of colours thrown up by random genetic variation and manufactured a colour distinctive enough to be named after the bird canary yellow. By the way, the bird itself is named after the islands, not the other way...

Up From The

Short of rocketing into space, it is hard to imagine a bolder or more life-changing step than leaving the water for dry land. The two life-zones are different in so many ways that moving from one to the other demands a radical shift in almost all parts of the body. Gills that are good at extracting oxygen from water are all but useless in air, and lungs are useless in water. Methods of propulsion that are speedy, graceful and efficient in water are dangerously clumsy on land, and vice versa. No...

Darwins map of the Galapagos islands with English names now seldom used

This disparity, between tens of miles as the distance between islands within the archipelago, and hundreds of miles as the distance of the whole archipelago from the mainland, leads the evolutionist to expect that the different islands might house species that are pretty similar to each other but more different from their counterparts on the mainland. And that is exactly what we do find. Darwin himself put it well, coming tantalizingly close to evolutionary language, even before he had properly...

Arcy Thompsons skull transformation

At the beginning of this chapter I introduced the idea of 'homology', using the arms of bats and humans as an example. Indulging an idiosyncratic use of language, I said that the skeletons were identical while the bones were different. D'Arcy Thompson's transformations furnish us with a way to make this idea more precise. In this formulation, two organs - for example, bat hand and human hand - are homologous if it is possible to draw one on a sheet of rubber and then distort the rubber to make...

Chapter Missing Link What Do You Mean Missing

P. 143 What do you mean, 'missing' html arti, p. 147 'already in an advanced state of evolution' Dawkins 1986 , 229. p. 151 'If people came from monkeys via frogs and fish, then why does the fossil record not contain a fronkey ' 'Darwin's evolutionary theory is a tottering nonsense, built on too many suppositions', Sydney Morning Herald, 7 May 2006.

Guppies

My colleague Dr John Endler, recently moved from North America to the University of Exeter, told me the following marvellous - well, also depressing - story. He was travelling on a domestic flight in the United States, and the passenger in the next seat made conversation by asking him what he did. Endler replied that he was a professor of biology, doing research on wild guppy populations in Trinidad. The man became increasingly interested in the research and asked many questions. Intrigued by...

Rats Teeth

Why, if it is so easy to improve the teeth of rats by artificial selection, did natural selection apparently make such a poor job of it in the first place Surely there is no benefit in tooth decay. Why, if artificial selection is capable of reducing it, didn't natural selection do the same job long ago I can think of two answers, both instructive. The first answer is that the original population that the human selectors used as their raw material consisted not of wild rats but of domesticated...

Chapter Dogs Cows And Cabbages

Why did it take so long for a Darwin to arrive on the scene What delayed humanity's tumbling to that luminously simple idea which seems, on the face of it, so much easier to grasp than the mathematical ideas given us by Newton two centuries earlier - or, indeed, by Archimedes two millennia earlier Many answers have been suggested. Perhaps minds were cowed by the sheer time it must take for great change to occur - by the mismatch between what we now call geological deep time and the lifespan and...

Unintelligent Design

This pattern of major design flaws, compensated for by subsequent tinkering, is exactly what we should not expect if there really were a designer at work. We might expect unfortunate mistakes, as in the spherical aberration of the Hubble mirror, but we do not expect obvious stupidity, as in the retina being installed back to front. Blunders of this kind come not from poor design but from history. A favourite example, ever since it was pointed out to me by Professor J. D. Currey when he tutored...

From So Simple A Beginning

We know a great deal about how evolution has worked ever since it got started, much more than Darwin knew. But we know little more than Darwin did about how it got started in the first place. This is a book about evidence, and we have no evidence bearing upon the momentous event that was the start of evolution on this planet. It could have been an event of supreme rarity. It only had to happen once, and as far as we know it did happen only once. It is even possible that it happened only once in...

Analogies For Development

Lunar Lander Development

It is surprisingly hard to find a good analogy for the development of living tissue, but you can find partial similarities to particular aspects of the process. A recipe captures something of the truth, and it is an analogy that I sometimes use, to explain why 'blueprint' is not appropriate. Unlike a blueprint, a recipe is irreversible. If you follow a cake recipe step by step, you'll end up with a cake. But you can't take a cake and reconstruct the recipe - certainly not the exact words of the...

Lenski experiment population density

What was going on What was it that suddenly happened to Tribe Ara-3 Lenski and two colleagues investigated further, and worked it out. It is a fascinating story. You remember I said that glucose was the limiting resource, and any mutant that 'discovered' how to deal more efficiently with glucose would have an advantage. That indeed is what happened in the evolution of all twelve tribes. But I also told you that glucose was not the only nutrient in the broth. Another one was citrate related to...

Chapter Missing Persons Missing No Longer

Darwin's treatment of human evolution in his most famous work, On the Origin of Species, is limited to twelve portentous words 'Light will be thrown on the origin of man and his history.' That is the wording in the first edition, which is the edition I always cite unless otherwise stated. By the sixth and last edition, Darwin allowed himself to stretch a point, and the sentence became 'Much light will be thrown on the origin of man and his history.' I like to think of his pen, poised over the...

The Lizards Of Pod Mrcaru

There are two small islets off the Croatian coast called Pod Kopiste and Pod Mrcaru. In 1971 a population of common Mediterranean lizards, Podarcis sicula, which mainly eat insects, was present on Pod Kopiste but there were none on Pod Mrcaru. In that year experimenters transported five pairs of Podarcis sicula from Pod Kopiste and released them on Pod Mrcaru. Then, in 2008, another group of mainly Belgian scientists, associated with Anthony Herrel, visited the islands to see what had happened....

Insects Were The First Domesticators

Roses tell the same story as dogs, but with one difference, which is relevant to our softening-up strategy. The flower of the rose, even before human eyes and noses embarked on their work of genetic chiselling, owed its very existence to millions of years of very similar sculpting by insect eyes and noses well, antennae, which is what insects smell with . And the same is true of all the flowers that beautify our gardens. The sunflower, Helianthus annuus, is a North American plant whose wild...

Bibliography And Further Reading

Last Chance to See. London Pan. Atkins, P. W. 1984. The Second Law. New York Scientific American. Atkins, P. W. 1995. The Periodic Kingdom. London Weidenfeld amp Nicolson. Atkins, P. W. 2001. The Elements of Physical Chemistry With Applications in Biology. Atkins, P. W. and Jones, L. 1997. Chemistry Molecules, Matter and Change, 3rd rev. edn. New York W. H. Freeman. Ayala, F. J. 2006. Darwin and Intelligent Design. Minneapolis Fortress. Barash, D. P. and...

Colour Sections

Page 1 The Earthly Paradise by Jan Brueghel the Elder, 1607-8, Louvre, Paris Lauros Giraudon The Bridgeman Art Library. pages 2-3 a Wild cabbage Brassica oleracea , sea cliffs, Dorset Martin Fowler Alamy b vegetable spiral Tom Poland c Bernard Lavery, holder of 14 world records, with one of his giant cabbages in Spalding, Lincs., 1993 Chris Steele-Perkins Magnum Photos d sunflowers, Great Sand Dunes National Monument, Colorado Chris Howes Wild Places Photography Alamy e sunflower field,...

Index

Page numbers in italic refer to illustrations in the text. Page nos in bold refer to illustrations in the colour sections. Page numbers refer to the printed version - page links direct to the first pages of the corresponding chapter. Acanthostega, 167-8 Adam and Eve, 7-8, 23, 213-14, 404n, 1 Adams, Douglas, 345 Africa age of rocks, 279-80 antelopes, 380 continental drift, 16, 273-4 elephants, 111, 113 Eocene beds, 171 human ancestry, 183-4, 185-6, 188, 196 lakes, 266-7 monkeys, 269-70 moths, 50...

No Choreographer

The early history of embryology was riven between two opposing doctrines called preformationism and epigenesis. The distinction between them is not always clearly understood, so I shall spend a little time explaining these two terms. The preformationists believed that the egg or sperm, for the preformationists were subdivided into 'ovists' versus 'spermists' contained a tiny miniature baby or 'homunculus'. All the parts of the baby were intricately in place, correctly disposed to each other,...

Lenski experiment bacterial body size in twelve tribes

What this evolutionary change suggests is that becoming larger is, for some reason, a good idea when you are struggling to survive in this alternating glucose-rich glucose-poor environment. I won't speculate on why increasing body size might be an advantage - there are many possibilities - but it looks as though it must have been so, because all twelve tribes did it. But there are lots of different ways to become larger - different sets of mutations - and it looks as though different ways have...

Family tree for Pennys eleven species

If molecular genetic technology continues to expand at its present exponential rate, by the year 2050 deriving the complete sequence of an animal's genome will be cheap and quick, scarcely any more trouble than taking its temperature or its blood pressure. Why do I say that genetic technology is expanding exponentially Could we even measure it There is a parallel in computer technology called Moore's Law. Named after Gordon Moore, one of the founders of the Intel computer chip company, it can...

Show Me Your Crocoduck

Atlas Creation

'Why doesn't the fossil record contain a fronkey ' Well, of course, monkeys are not descended from frogs. No sane evolutionist ever said they were, or that ducks are descended from crocodiles or vice versa. Monkeys and frogs share an ancestor, which certainly looked nothing like a frog and nothing like a monkey. Maybe it looked a bit like a salamander, and we do indeed have salamander-like fossils dating from the right time. But that is not the point. Every one of the millions of species of...

Into A Few Forms Or Into

Darwin was right to hedge his bets, but today we are pretty certain that all living creatures on this planet are descended from a single ancestor. The evidence, as we saw in Chapter 10, is that the genetic code is universal, all but identical across animals, plants, fungi, bacteria, archaea and viruses. The 64-word dictionary, by which three-letter DNA words are translated into twenty amino acids and one punctuation mark, which means 'start reading here' or 'stop reading here', is the same...

Placental and marsupial opposite numbers

In animals, unlike bacteria, gene transfer seems almost entirely confined to sexual congress within species. Indeed, a species can pretty well be defined as a set of animals that engage in gene transfer among themselves. Once two populations of a species have been separated for long enough that they can no longer exchange genes sexually usually after an initial period of enforced geographical separation, as we saw in Chapter 9 , we now define them as separate species, and they will never again...

Illustrations In Text

Figures in the text on the following pages were redrawn by HL Studios 90, 149 both , 153, 166, 167, 168 both , 173 both , 176, 177, 186, 187, 189, 191, 192 both , 193, 196, 222, 225, 227, 228, 230, 231, 232, 287, 289, 290, 294 both , 295 both , 300 all , 302, 304, 307, 343, 346, 347 both , 350 both , 354, 357 and 365. page 7 'I still say it's only a theory', cartoon by David Sipress from the New Yorker, 23 May 2005 The New Yorker Collection 2005 David Sipress from cartoonbank.com. All Rights...

Thylacine marsupial wolf or Tasmanian tiger skull

Thylacine Nose

The sexual shuffling of the genes in a gene pool could be regarded as a kind of borrowing or sharing of genetic 'ideas', but sexual recombination is confined within one species and is therefore irrelevant to this chapter, which is about comparisons between species for example, comparisons between marsupial and placental mammals. Interestingly, high-level borrowing of DNA is rife among bacteria. In a process that is sometimes regarded as a kind of precursor to sexual reproduction, bacteria -...

The Pernicious Legacy Of The Great Chain Of Being

Underlying much of the fallacious demand for 'missing links' is a medieval myth, which occupied men's minds right up to the age of Darwin and stubbornly confused them after it. This is the myth of the Great Chain of Being, according to which everything in the universe sat on a ladder, with God at the top, then archangels, then various ranks of angels, then human beings, then animals, then plants, then down to stones and other inanimate creations. Given that this goes way back to a time when...

Endless Forms Most Beautiful And Most Wonderful Have Been And Are Being Evolved

I'm not sure what Darwin meant by 'endless'. It could have been just a superlative, deployed to soup up 'most beautiful' and 'most wonderful'. I expect that was part of it. But I like to think that Darwin meant something more particular by 'endless'. As we look back on the history of life, we see a picture of never-ending, ever-rejuvenating novelty. Individuals die species, families, orders and even classes go extinct. But the evolutionary process itself seems to pick itself up and resume its...

Conchomorphs computergenerated shells shaped by artificial selection

Darwin had first-hand experience of the power of artificial selection and he gave it pride of place in Chapter 1 of On the Origin of Species. He was softening his readers up to take delivery of his own great insight, the power of natural selection. If human breeders can transform a wolf into a Pekinese, or a wild cabbage into a cauliflower, in just a few centuries or millennia, why shouldn't the non-random survival of wild animals and plants do the same thing over millions of years That will be...

Biomorphs from the Blind Watchmaker program

The game starts to get interesting when we consider the 'embryology'. The embryology of a biomorph on the screen is the process by which its 'genes' - those numerical values -influence its shape. Many very different embryologies can be imagined, and I have tried out quite a few of them. My first program, called 'Blind Watchmaker', uses a tree-growing embryology. A main 'trunk' sprouts two 'branches', then each branch sprouts two branches of its own, and so on. The...