Truth
Evolution for Fundamentalists 1
Abstract
Biologists are unanimous in concluding evolution is a fact. The evidence… adduced over 150 years falls together in intricate and interlocking detail. The multitudinous examples range from small changes in DNA sequences observed as they occur in real time to finely graded sequences within larger evolutionary changes in the fossil record.Pulitzer prizewinner, Professor Edward O Wilson, a brilliant biologist, brought up a creationist!
© Dr M D Magee
Contents Updated: Tuesday, 20 December 2005
Who Needs Evidence?
Christian creationists are fond of asking their evolutionary opponents for evidence of evolution, a fatuous demand since the creationists have no evidence at all for creation by God, and indeed do not even have any evidence for God. Yet the evidence for evolution is so voluminous that it would take a lot of bible sized books to summarize it adequately. That, though, is their point. Their demand for evidence is a ploy meant to make their evolutionist opponent hesitate and seem evasive. The evolutionist pauses to think where shall I start, and the hesitation gives the creationist time to butt in and bombast, wrong-footing the evolutionist even more, seeming to catch them out, and winning a dubious debating point—at least for sad fundamentalists, though not for anyone intelligent.
It happened when Robert Winston, a practising Jew and biologist, met some weird creationist when he was making his three part TV programme, the Story of God. Invited to a debate on some local radio channel the creationist hectored Winston, ruffling his composure, and seeming to come out on top, to judge by the fraction of the debate shown. Winston was polite even when he was accused by the weirdo of demeaning “my bible”, though Winston could more justifiably have called it his bible, as a Jew, the Christian Old Testament being the Jewish scriptures stolen by the gentile Christians. The whole charade is simply to seem to embarrass a naïve evolutionist by dishonest ploys because no fundamentalists need any evidence for their beliefs—just as well when they have none—so there is no debate anyway.
These schemers want to extract lucre from gullible believers, just as Christian tricksters and evangelists have always done. This bizarre example has apparently conned $25 million out of simple Christian sheep to build a gigantic coprolite called a museum of creation. The simple creationists who attend it will not notice that it is full of mechanical dinosaurs, chosen because these charlatans know what will attract the simple, even though dinosaurs have nothing to do with the bible or Genesis at all, and would not have been known about had it not been for careful scientific investigation. So too, the credulous creationist gapers will not think for a moment that the electro-mechanical wonders they are gaping at are the outcome of the wonders of scientific discovery not the revelation of God and his angels. You cannot expect dimwitted fundamentalists to realise such things or the contradictions in them.
The dimwits not infrequently challenge the author of these pages to provide the evidence for evolution, and hitherto the response has been that they should not expect to be spoonfed like babies but should try reading any one of a large number of excellent books that have been published on evolution. The Origin of Species is, for example freely available to download on the web. They are not, of course, interested in any such evidence, or they would not need to ask for it. In fact, the book, Who Lies Sleeping?, accessible through these pages, briefly explains evolution, so these twerps do not even want to disguise their idleness and ignorance. After all, it must be God-given!
Then a letter to the New Scientist (5 November 2005) mentioned that the effect of the creationist campaign against science in the US is that good school science teachers are in short supply, and few school textbooks deal adequately with evolution, so pupils are left inclined to think the dishonest creationists are right and the evolutionary case is weak. It gets worse. Even though Britain is a secular society with few people interested in religion, some science students in British schools and universities intending to become pharmacists, doctors, geneticists and neuro-scientists also say Darwin was wrong! Many of them are not evangelical Christian creationists, as anyone might expect, but Moslem ones! Moslem medical students in London distributed leaflets produced by the Al-Nasr Trust, a charity supposedly to improve understanding of Islam but which prefers to deny Darwin. So, Moslems are creationists too, from the Quran saying animals had been created, so had not evolved:
And God has created every animal from water. Of them there are some that creep on their bellies, some that walk on two legs and some that walk on four. God creates what he wills for verily God has power over all things.
These three sentences are set against volumes and volumes of scientific proof of evolution, even though they scarcely contradict it! Students of the science of medicine dismiss on no scientific grounds one of the most important idea of biological science, and one established by 150 years of observation and experiment. Modern medicine is a science, so it should worry people that future doctors cannot understand it, or choose not to in favour of false ideas from “holy books” so-called. It is hardly surprising that cartoonists depict the prophet of Islam as a madman.
The Royal Society, Britain’s leading scientific institution, invited geneticist Professor Steve Jones of University College London to give a talk Why Creationism is Wrong because our education system should resist misrepresentation of science to favour religious belief. Jones thinks creationists…
…don’t have a problem with science, they have a problem with argument. It’s a step back from rationality. And irrationality is a very infectious disease as we see from the United States.
Here then is an outline of the case for evolution and the creationist arguments against it. Anyone who turns to this short account should remember that the evidence is far-reaching and profound, yet Christian creationists set it against the first two chapters of Genesis, a fairy tale written for Syrians 2500 years ago, not for modern Yankees. It is a simple nursery explanation, sufficient for infants and simple people unable to understand that the world is not simple. The answer in schools and universities is to fail students who try to pass off ancient folklore, however revered it might be, as science. To refuse to accept the scientific method in science faculties must mean failure! Fundamentalists take their God to be made in their own image—a dunce!
Creation and Spontaneous Generation of Life
So creationists invert reality, and their disciples do not even notice the deceit. They teach their uncritical disciples that proper science has united to manipulate public thinking and to exclude anyone, not in the cabal of professional scientists, from any control over science for the public good, while creationism addresses a public alienated from an arcane or impersonal science which offers no meaning to their lives. So, creationism:
• projects its own faults on to its critics, knowing that believers will not notice, despite the crudeness of the trickery,
• labels its evolutionary opponents, proper scientists, as unscientific and desperate to preserve their own arbitrary view of the world rather than seeking objective truth, while its own variation of an ancient theme is offered as truly scientific,
• explains scientific rejection of its own mythical construction as through scientific prejudice and conspiracy, not because of any faults in it.
Creationism, falsely presented as if it were logical and consistent, merely offers the age old unfounded beliefs of the religious scam—our undetectable souls and an undetectable but almighty creator God. Creationists cannot understand that:
“To read the first chapter of Genesis as though it were an exact account of the origins of life is not only bad science, it is also bad religion.”
For 1800 years Christians insisted that the bible account of creation was not only true as an account of how God made everything in the world, but proven daily—it still happened! They believed that animals were being spontaneously created all the time. If God could create everything from herbs and fish to birds and mammals, all in one go, it must be possible for Him to do it one at a time. In the whole of this time, Christians did not doubt that mice were made spontaneously in dirty linen, and that maggots spontaneously generated on dead meat. It is laughable now that science has shown otherwise but for 90% of the existence of Christendom, it was what educated Christians believed and taught because it did not contradict the infallible collection of tall stories called the bible.
F Redi, in the seventeenth century had the novel idea of taking the precaution that every US housewife now does and kept the meat screened from flies. The meat went putrid but not a maggot spontaneously generated in this ideal environment for them. Exposed to flies, the meat quickly yielded maggots, and eventually flies just like their parents hatched from the cocoons the maggots made. In the nineteenth century, Louis Pasteur demonstrated a principle that has helped us immensely in many ways. He showed that putrification itself is caused by invisible microbes getting on to a corruptible substance and rotting or fermenting it. He conclusively showed by boiling a broth that it could be kept indefinitely without putrefying as long as the air was kept out so that the microbes it carried could not get in.
The word used today is to keep something sterile, and it has meant that thousands of lives have been saved and billions of dollars saved too by avoiding putrefaction in food and drink, and days lost through infected wounds. These great discoveries were not made by revelation. They did not come from the holy book. Quite the opposite. Unquestioning belief in the holy book had for cruel centuries prevented these discoveries from being made. So, one aspect of the belief in creation—spontaneous creation—is demonstrably untrue, and uncritical belief in it has had awful consequences, so no creationist will believe in spontaneous generation today. If God made anything “in the beginning”, he stopped doing it thereafter, but Christians could not bring themselves to accept it until only 150 years ago. Yet they will not let go of the “in the beginning” bit.
Science has never been revealed by God or angels, and anyone who honestly prefers the infallible bible to science ought to do the honest thing and reject science all together. You will notice that, despite the bombast of these fundamentalist confidence tricksters, they will not give up their science based luxuries, including their radio stations. When did God reveal the secret of electro-magnetic waves? Christians have always been hypocrites, even though their own God decried hypocrites in no uncertain terms. Science takes a lot of careful study and effort to yield results that have any practical value in the world. Thick-headed evangelists cannot get their brains round it and so try to denigrate it, but, if they ever succeeded, they would have to add a few more revelations to the holy book to bring back science as revelation.
Taxonomy
• Everything flows and nothing stands still.
Change is evolution. Evolution has become a powerful unifying factor in science. The universe is continuously changing, evolving from one form into another from the Big Bang onwards. Everything is related to everything else. Cosmology shows it on the universal time scale, but it can be seen in almost every science subject—physics, astronomy, geology, chemistry, biology and anthropology. What is particularly interesting is the way complexity seems to increase over time. But it does not do so monotonically or uniformly. Systems that have some structure, and therefore order, such as galaxies, stars, planets and life forms, form with corresponding oceans of disorder around them. This is a law of thermodynamics.
A problem is how to measure complexity. Energy is the universal measure of the ability to do work. Free energy drives order to emerge from chaos. Chaisson suggests energy flow per unit mass as a general measure of complexity, and is itself easy to measure. Energy per unit time per unit mass increases for all ordered systems over more than 10 billion years of the universe’s existence. Stars grow in complexity as their energy flow per unit mass steepens—more information is needed to describe them as they age.
Higher energy flow accompanies complexity throughout biological evolution. Life forms process more energy per unit mass than any star. The greater the complexity of a living system, the greater the flow of energy density through that system. Energy flow can model cultural as well as scientific concepts, the energy flow accompanying the growth in complexity of society growing in proportion from hunter gathering, through agriculture into industry.
And selection happens in all evolution, though “selection” is a poor word for what happens in Nature. It implies an agent that does the selecting, and so panders to the religious idea of a god. Golf courses are not littered with golf balls even though the owners of them bat them with their clubs into fields. Generally they retrieve their ball and bat it further until they finish their game. But drain a pond on a golf course and golf balls will be littered in the mud of it. Their owners could not retrieve them. The pond is selecting golf balls from among those batted towards it. The chances are against any ball landing in the pond, since golfers are trying to avoid it, but even so some do. By chance they are mishit, land in the water, and have little chance of being picked up again. That is the essence of selection. It becomes certain over time that the pond will have collected more golf balls than the rest of the golf course. Overall it is not a chance process. At the beginning of life, chemical selection tamed chance, as Chaisson puts it. That is what Christian fundies refuse to accept as being possible.
A strip of fly paper is similar. The fly will hit it randomly, but will not escape randomly. Chaisson points to crystal growth as being like this. To grow a crystal, molecules in solution must hit the surface of the crystal, and stick there rather than bouncing off. At some points on the surface, the forces of attraction hold the colliding molecule in place, whereas at other points they do not. Thus the crystal grows in a particular, ordered way, even though the molecules are hitting the crystal surface at random. The arrival of the molecule is random, but the outcome is not.
These mechanisms of selection each help build order and complexity by mixing a random event with a response detemined by some distribution of energy acring as a determinative force. This principle lies at the root of the whole universe, not just biology. Natural selection is the elimination of the least effective possibilities. Ordered systems are —selected by their use of the energy in the Goldilocks principle of not too hot and not too cold but just right. Too much energy can be destructive, and too little can be ineffective. The system with optimum energy usage is most likely to survive.
In chemistry, bonds which are too strong make molecules that are hard to change—they need too much energy—and those which are too weak make unstable molecules—they fall apart with only a little energy. Ideal are weak bonds multiplied in effectiveness by their quantity. They are strong but flexible enough to be broken by a steady application of energy. The amino acids present in hot pools of “primeval soup” could combine in many ways, but only some of them had the flexibility needed for life, and these were the ones that eventually formed life. Only those that are able to survive in particular circumstances do so. In other words, they are the forms that better suit the environment. Those that do not go extinct. That is biological evolution.
Evolution did not just appear one day out of the blue, a whim of God. It was deduced from previous evidence painstakingly assembled. Absolutely basic to it was that life as we see it today always comes from life already existing. Flies produce a new generation of flies, and human beings produce human beings. The process is called reproduction, and involves what Christians cannot bear—sex! For evolution, the sex is not primary, though it is important. Notice that offspring are not identical to their parents, especially when reproduction is sexual. Everyone agrees that individuals differ from generation to generation, even Christians, and species can and do change noticeably, though to a small degree, over short time period. Mankind proves it, on the Christian thesis that all humans began with Adam, since we now have several distinct races. There is a chain of being that creationists must accept began with the first animals made by God at the creation and has continued ever since, but each succeeding creature can differ from its parents, so reproduction does not make identical copies. Each generation is a bit different from the previous one. Just imagine where these slight differences can lead over many generations! Christians and pious Jews think Adam’s descendents were Ham, Shem and Japhet, Africans, Semites and Indo-Europeans. Maybe a mouse can become an elephant, and an ape a human being!
Professor R Dawkins calculates that, in 12,000 generations, a rate of growth of 0.02 per cent per generation, a change too small for any contemporary observer to notice, would allow an animal the size of a mouse (40g) to evolve into an animal the size of an elephant (6 tonnes). Mice sized mammals reproduce quickly and the time between each generation is short, whereas elephants reproduce more slowly and there are many years from generation to generation, but taking 5 years as an average over the whole time, the change of mouse to elephant would have happened in 60,000 years. Anything but instantaneous, the change would appear instantaneous in the rocks. In the geological record the shrews will have given way to elephants in adjacent strata as if they had appeared from nowhere—instantly created by God!
In the nineteenth century, observers had also noticed that creation was made up of species, types of creature that did not interbreed. These were the creatures made by God “in the beginning”, according to Christians. Some Christians, among them Linnaeus, thought it would be a good idea to list all god’s creatures in a big catalogue. He was surprised to find that a lot of species were remarkably alike, so alike that he decided to catalogue them together calling a group of similar species a tribe of species, a genus. Having done it, he found that even the tribes could be put into bigger groups on the basis of similarity, forming a taxonomy or hierarchy of types.
Why should Linnaeus have been surprised? Christians tell us that God the creator is almighty. He can do anything He likes. Millions of modern Americans think God can do impossible things like squaring the circle, so He could certainly have no trouble at all in coming up with a totally unrelated creation, in which every creature occupied its own space and had no features the same as others. Even Genesis noticed that there were birds and fish and herbs and animals, apparently separate types, but commonalities were found among them. A God that is almighty, and can do anything at all, need not have been confined to any particular plan that He kept repeating with minor variations, yet that is what the taxonomists found. God’s creatures showed no evidence of being independently made, and every sign of being modelled on a master plan.
What was so special about a tube design? God preferred it. Why do vertebrates overwhelmingly have five digits and four limbs? God preferred five and four as His prototypes for higher animals. Why? Why were there no animals like stools with three legs, or armchairs that sing like birds, or seven headed hydras? Why were there no dragons or unicorns or centaurs? Why were there no animals that had wheels instead of legs, or balloon creatures that floated in the air trapping insects? Or mixed designs, like fairies, animals with insect wings, or horses with wings like Pegasus. They never happened, yet an almighty could have made them. It is an inexplicable fact for a creationist, but just what evolution predicts.
As soon as you have a taxonomy like the one that Linnaeus produced, showing a hierachy of groups of similar life forms, when an all powerful God could have made a random collection of completely different and original life forms, the notion of individual creation of species is put into question. Christians are easily satisfied, like Moslems, by the belief that God does just as He pleases, and He chose to make creatures based on a taxonomy. It is not an explanation! For believers, it is a mystery of God, and they are content to leave it at that, fearful that God is not as loving as they say, and might take umbrage at their questioning Him. Should the pot question the potter? Well, when the potter has given the pot a brain, why not? Is the pot not meant to use it? Christians think not, but scientists think so. God must have given them it so that they would use it!
Unlike gullible believers, scientists are never satisfied to be fobbed off, and even those curiosities who are both scientists and Christians can see nothing wrong in scientific enquiry. Despite his Christian faith, Linnaeus knew what his discovery implied—evolution! God had deliberately allowed some at least of his creatures to evolve, and all creation did not happen at once, as the infallible bible says. Genera and families of species must have arisen from a creature of the original creation evolving into a variety of different forms. To think otherwise meant God deliberately created things to seem as if they had evolved, and there could be no purpose in that except deception.
In those days, no one could contemplate that a good and loving God could be deliberately deceitful. They rejected any such idea. Maybe God nowadays, in the country of lying Presidents, is a liar Himself. If so, He is more likely to be the Devil than the God Christians hope He is. It is quite impossible to imagine a good God who is a deliberate liar, whatever President Bush, and PM Blair might think. If creatures looked as if they had evolved, then the likeliest explanation was that they had evolved. When almost all creatures in the taxonomy of all species seem related in some way to other ones, then evolution is practically certain.
Darwin’s Hypothesis
Evolution researchers are now doing laboratory experiments just like physicists, rather than being confined to observation in the field. Emily Singer explained in the New Scientist how they can set up colonies of bacteria and watch them evolving because they replicate quickly. The experimenter can act as God to the bacteria, changing the environment to see what happens to the evolution of the organisms. They find that microbes can adapt quickly to new environments, can produce new strains to fit into new niches, and can evolve to cope if conditions turn hostile. Elaboration of this work is revealing how communities can adapt over time. Evolution is open to experimental analysis, controlled investigations and repeated studies.The size and complexity of natural ecosystems makes it difficult to determine whether a particular change is due to variations in the environment, pressures from neighbouring species or more random factors such as genetic drift. In the lab, biologists can individually change relevant factors controlling microbial populations, such as various aspects of the environment, and note the evolutionary outcome.
Evolutionary biologists imagine an organism’s genetic possibilities as a landscape in which evolution flows like water until the organisms reach a lake, standing for a stable species. Mountain tops are unstable situations, notionally cold, airless and arid, that species might find themselves stranded in when their actual environment changes suddenly. They will die off in the unsuitable environment unless they flow downhill—evolve—quickly into more stable places in the evolutionary landscape. Perfectly adapted organisms are the lakes in the valleys. A small but stable population in a perfect environment is in an evolutionary puddle and notionally cannot get out. But there are tendencies to drift off the expected valleys cut in the landscape. Genetic drift can let a species, especially isolated ones, change anyway, allowing it to move at random to another place in the evolutionary landscape it otherwise could not have reached. Then it can begin to evolve anew along different evolutionary paths with possible different outcomes.
Competition from one microbe may influence the evolution of another in ways that are difficult to predict. Predator-prey interactions can drive microbes to evolve along divergent paths. Growing 12 populations of a single strain of Pseudomonas fluorescens together with one of its parasites, a bacteriophage, yields after 50 generations much greater genetic variation. Each strain evolved a distinct way to resist the phage (Nature 420). Unusual abundance of food can also apply evolutionary pressure. A flask of unusually rich glucose solution was used for an E coli microbial culture. The bacteria flourished in the food rich environment, but soon, there were so many bacteria competition had arisen even for the originally excess food. Then weaker bacteria ought to have died off, unable to stand the competition, but what happened was that they evolved the ability to feed on the waste of glucose metabolized by the stronger competitors. It shows that a simple ecosystem can evolve.
One of biology’s central questions is “How did multicellular life emerge?”. The problem for experimental biologists acting as the microbial god is to get single celled organisms to work together. Cooperation is common in nature, but the puzzle why it would evolve when survival seems selfish. Organisms must benefit for group cooperation to be selected. German biologists cultured the bacterium Myxococcus xanthus. It cannot spread across solid surfaces unless individuals cooperate by sprouting tiny appendages known as pili and then swarming en masse. A strain that could no longer produce pili was cultured to see whether it would re-evolve the ability to swarm. Two new swarming strains emerged, but they did it in a different way. Instead of growing pili, they excreted a slimy glue that held the cells together while they moved across the surface using the cellular flagellum that normally drives individual cells (Nature 425). Primitive cooperation can easily occur at that level. So bacteria can evolve co-operative behaviour in the lab when the conditions require it.
In another instant, a strain of Pseudomonas fluorescens colonized the interface between air and liquid in a flask full of nutrient broth. The microbes produce a gluey substance that allows the bacteria to form a raft. The glue costs the bacteria energy to produce, and this slows their growth rate. What compensates to allow selection is that the bacteria forming the raft have unlimited oxygen from the air, while those living in the liquid have only a restricted oxygen supply. On the raft, the colony of individual bacteria have evolved cooperative behaviour. As it does not seem difficult, the step from single celled to multicellular life is no longer a conceptual barrier to the evolution of complex life.
Test tube experiments in evolution are a simple way to observe evolution happening and to test hypotheses about it. Empirical evolution can help unravel evolution in the past and how human activity is shaping life today.
We all know that Christians either cannot understand scientific method, or they refuse to. Science does not end at collecting data. That is only the beginning. Science then has to formulate an hypothesis that will show as completely as possible how the facts can be explained. “How?” is the basic question in science when seeking an explanation of a collection of facts. A supernatural “explanation”, that will satisfy Christians is not an explanation for science, something that Christians just cannot get into their tiny heads. The reason is that a supernatural “explanation” is no explanation at all. Any difficult phenomenon can be fobbed off with a supernatural “explanation”, but, we saw, scientists will not be fobbed off. The supernatural can “explain” anything, and therefore it “explains” nothing.
The whole objective of science is to find natural explanations because we live in a natural world, and this principle of science has allowed us to understand this natural world better than we have ever done before, including in the 1600 years of Christian revelation that preceded the start of the scientific revolution. It is why the so-called “theory” of Intelligent Design is laughable as science. It invokes the supernatural, explains nothing, and instead of being fruitful—that is, leading on to further discoveries—it stops enquiry dead in its tracks. At one time, creationists were fond of parroting “evolution is only a theory”, but now they have their own “theory” that they want to defend, so do not use the “only a theory” argument any more. The “only a theory” argument used the word “theory” to mean an untested speculation, like the “theory” a fictional detective might devise to offer a rationalization of a crime, but that it exactly what scientific theories are not. In science, a hypothesis begins untested and it is through surviving the crucible of testing that it earns the description “theory”. When using the word “theory” in the phrase “the Theory of Intelligent Design”, it is not being used in the scientific sense, but in the fictional detective sense—it is untested and must remain forever untested because it cannot be tested—and that is why must be written in puzzlement marks.
The closeness in similarity of many of God’s creatures suggested that they were related in reality because they had evolved from a common ancestor, but a natural mechanism was needed to explain it. Everyone can see that children are not identical to parents, but have some common features. The immediate idea to explain evolution was that acquired characteristics were somehow passed on to children. It is half an explanation, but it too explains nothing unless it can go further and explain how the acquired characteristics are passed on to the next generation. It could not.
Darwin and Wallace set up evolution as a proper scientific hypothesis, and both were practising Christians, though Darwin learnt some sense. At this time, most people in the UK were routinely brought up as Christians, so it would have been hard and unusual to have found someone who was not Christian even though no bigotted ministers were waiting to burn the heretic or atheist at the stake, as they were in Europe only a century before. Most of the early scientists were Christians for this reason. It had nothing to do with some Christian dynamic towards scientific greatness.
Darwin and Wallace saw that it was not a matter of passing on acquired characteristics, but characteristics the creature already had that served it better than those of some of its fellows. The creature with characteristics that did not serve it so well, had a greater chance of dying early. If it died before it had mated, then its characteristics were never passed on. If it mated less often, or could attract less robust mates, then it would have fewer offspring than the creatures with the best characteristics. The effect over countless generations is that some characteristics are favoured in an environment and some not, and the latter gradually disappear as the owners of them fall in proportion in the population and eventually die off.
These Christian men had confirmed what was to them a remarkable fact—that God had not made all creatures completely from scratch at the creation, thus making a collection of living creatures as unclassifiable as the grains of sand on a beach. Evidently, he had made some prototypical creatures and then left them to evolve. In the nineteenth century, this was the core of the theory of evolution, submitted as an hypothesis to explain the taxonomy of God’s creation, an indisputable fact of Nature. The success of Darwin and Wallace was the rules they put forward to explain how evolution happened, not the fact that it did. Without these rules, scientists could have joined with Christians to doubt evolutiuon, simply because there was no explanation of how it could happen. The Darwinian hypothesis suggested three driving forces of evolution:
- Variation—Not all creatures are the same and even small differences can be important to survival.
- Inheritance—Creatures pass on their innate characteristics to their young.
- Overpopulation—Far more creatures are born than survive to adulthood. Those that fail to breed are either unlucky (a random factor) or are not suited to their environment in some respect, however small.
A creature born into a particular environment with certain characteristics inherited from its parents and adequately suited to its environment will survive to breed and give birth to a new generation which will inherit its characteristics. The cycle continues—the species survives. Another creature is badly adapted to it environment, say a black polar bear or a mute blackbird. It is unlikely to breed successfully and the variant feature that led to its failure will not have the chance of appearing again in the next generation. Black polar bears and mute blackbirds quickly die out.
These examples illustrate selection against gross differences in features but Darwin regarded evolution as occurring through an accumulation of small changes caused by the selection of small variations inherited from parents. Such small variations do not prevent breeding, but tip the scales slightly. A grey polar bear might be able to pass on its greyness for many generations because ninety nine times out of a hundred it is as successful in catching seals as its white rivals. But that one time out of a hundred that the white bears are more successful than the grey ones will ensure that the population of polar bears will eventually be all white. Over generations of natural selection that tiny difference favors the white variety. Equally, the persistence of a minute inclination to grow allows the 40 g shrew to grow into the 6 tonne elephant.
Evolution does not happen by chance in the sense that improvement happens at random instants of time. It is too unlikely that random hits will lead anywhere. Consider that someone confined to a wheelchair will have a lot of difficulty pushing it up some steps, but will have little difficulty in pushing it up a gradual slope. What cannot happen in noticeable steps can happen imperceptably, and that is what evolution is about. To imagine a functioning eye appearing overnight is to imagine the impossible, but a gradual accumulation of properties such as light sensitivity in cells can lead eventally to a rudimentary eye, and then further gradual evolution leads to a sophisticated eye. This happens because each living creature has inherited the genes of its parents, and when the parents have genes that give them an advantage in breeding, they will have more offspring each with the advantageous genes.
A purely chance mutation will most often make the creature worse off than it was without it, but sometimes will leave it better off, and then that advantageous mutation spreads through the population by sexual reproduction until all have it. Disadvantageous mutations leave the individual worse off, less successful at breeding, and so eventually it dies out in the population. It is not at all random. All that is random is the mutation, but selection is not random. What is unsuitable for the organism in its conditions makes it a poorer reproducer than its neighbours and the genes fade out, while what favours reproduction in the environment, spreads and eventually is common to all members of the species. Only people who are utter dunces can call this process random. Christians do, and particularly fundamentalist Christians. Either they know it is not random but want to discredit evolution anyway because it does not suit their faith, so they lie about it, or they genuinely think it is random meaning they have not considered it properly and really are dunces or refuse to look properly at it for fear that it might be true.
In Darwinian evolutionary theory, evolution should occur gradually and the gradual changes should be visible in the fossil record. They rarely are. Darwin was unhappy that there was not a smoother fossil record, despite the fact that fossilization is a rare and haphazard process. Species seemed rather to live unchanged for a long time then change suddenly to something new. Eldredge and Gould’s theory of punctuated evolution explained this apparent anomaly, extending Falconer’s ideas of Darwin’s time. When it is well adapted to a stable environment a species can experience a long period of stability.
Even then, the random factor called genetic drift can cause a slow change in the gene base of the population of creatures that can produce some change, and possibly an instability in the adaptation to the environment. In any event, sometimes the species then suddenly evolves very quickly, perhaps within ten to a hundred generations. Since geologists can rarely measure intervals in the rocks of closer than 100,000 years, such a rapid change occurs in too short a period to leave a fossil record. It seems as though one species had suddenly given way to the newer one. The mouse gave way to the elephant in Dawkins’ example.
Now, critics of Darwin were on sounder ground in 1860 than the creationists are today, and, if they hope to argue against Darwinism from facts at all, they often have to revert to arguments of that time to seem to make a case for their struggling acolytes. The central major fact to explain until then was the fact that God’s unique creation could be classified as a taxonomy. Within that major fact, though, was a mass of detail some of which Wallace and Darwin collected on their field trips overseas. Darwin reviews it all painstakingly in his book, On the Origin of Species, the book that no creationist can read in case God starts heating up, in readiness to receive them, the fires of hell.
Among his famous examples were the Galapagos finches, almost identical little ground feeding birds which differed only in that they had evolved to suit different types of food on the islands, and therefore differed mainly in the way their beaks had adapted to the food available. The creationist explanation could only be that God was tired or idle and chose to make all the birds from the same blueprint simply changing the beaks. Why was God so unoriginal here? An Almighty could have done anything, but did not, and we cannot know why He did not. That is why God is no explanation. What is an explanation is that the birds all evolved from a few of a species of finches that were blown to the islands, and had to fend for themselves. They adapted into the forms that can be seen.
The Evidence of Genetics
The soil bacterium Pseudomonas has four genes it uses to break down atrazine, scattered at random in its genome, suggesting that they were picked up one at a time. Also transposons, labile DNA, around them suggest genetic shuffling. It seems they have picked up genes from nearby strands of DNA. Even so, they will not have worked to break down what had never been met before. The genes had to mutate unusually quickly to give them the chance to change into something that could handle the poison. Curiously, a gene, DNA polymerase V, activates in times of stress. It is an inexact copying gene. It is a poor copier, making errors that are genetic mutations. More mutations gives the bacterium a greater chance of throwing up a combination that can handle the situation better, is selected and allows the bacterium to survive by consuming chemicals that otherwise would have been poisonous. The bacteria have a natural defence mechanism against environmental stress that makes for rapid evolution.
The big questions that remained at the time over Darwinism, as it came to be known, were about variation and inheritance, poorly understood as they were then. Essential evidence existed but it remained unnoticed for another forty years before it was brought to public attention in 1900. It was the work of the Christian monk, Gregor Mendel, who had meticulously studied the inheritance of variations in peas in mid-century, deriving some rules of inheritance. Once noticed, his work gave rise to the science of genetics that would fully explain how evolution occurs at the molecular level. Experiment showed that genes were either dominant ones, which were commonly expressed if the creature had the gene, and recessive ones which were not necessarily expressed. Moreover, genes changed by mutation—they spontaneously altered themselves—allowing new types of characteristics to arise. Mostly these have no effect at all or are harmful, spoiling fitness to reproduce, but a small proportion are not and so improve fitness. It is this that ensures that evolution is not random, even though genetic mutation is! And the neutral mutations build a store of ready made variation into the genetic code of organisms that has no effect at all as long as the environment remains stable, but can be very important for survival when it changes.
In 1953, F Crick and J D Watson published the structure of the DNA molecule, the blueprint of life. It was two helices intertwined and loosely bonded along the centre rather like a zip fastener. The zip could unzip leaving the two bare molecules and these could then grow back using molecules in the locality as food to make the double helix again for each of the strands of the zip. One DNA molecule had therefore reproduced to make two of them. Then the process could continue to make four and eight and so on, as long as the supply of nutritional molecules remained.
The DNA strands exist in the chromosomes of all living cells, and the structure proposed by Watson and Crick explained reproduction at the molecular level—and so evolution. The DNA could evolve when small copying errors (mutations) happened in the reproduction process. If the new type of DNA molecule gave the parent creature bad characeristics, it was unfit for its environment and the creatures that had this DNA eventually died off, and the DNA with it. But if it gave the parent creature useful characteristics then the parent creatures succeeded better than others, and that type of DNA multiplied in the population. As the DNA altered, the species of the creature changed too, explaining evolution completely. The store of variety in the normally neutral genes activates when the environment alters. A small proportion of bacteria are normally immune to antibiotics, but if the environment slowly gets rich in antibiotics, the ones that have the resistant variation will survive and reproduce until it is the only type remaining. The antibiotic is then useless against that bacterium.
It is quite impossible to pretend that this DNA structure is not the ultimate evidence for evolution. There is absolutely no room to doubt it any more, it is so well established with a mass of evidence, and DNA is now used for routine investigations. There is no doubt that life depends on the DNA genetic code, and that it works as outlined here. Creationists have to explain how evolution does not happen with this zip-like molecule at the base of life! If this is disregarded, we are back to the idea that God is deliberately deceiving us. If He is, then the creationists have to explain why God would want to do it, and why, if it is a deception, it works in tests, techniques and technologies, but not in Nature, apparently. Or do the creationists deny that DNA is what it is, in which case they have a lot more explaining to do because DNA does everything that it is expected to do, and tons more is yet to be discovered about it. It is the fruitfulness part of scientific method, the part that creationism kills dead.
