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10:23

Mote Prime > Science

Discover Creation

A Review of Richard Dawkins's Talk "Discover Creation", 20 February 1997, Kenton Theatre, Henley-on-Thames, Berkshire, UK

Introduction

First, I would like to point out that this is not a complete transcript of the talk, but is extrapolated from notes taken during the course of the evening. Direct quotation is reported as usual in quotation marks, everything else is reported speech. Thanks must go to John Catalano for publishing the information that lead to my attendance.

Discover Creation

The Kenton Theatre is a relatively small and cosy place, and on the evening of February 20th its stage was graced only by a simple lectern. Without fanfare or introduction, Dawkins walked out to it confidently and waited for the chatter to die down.

Book Cover: The Selfish Gene

''Darwin's Birthday Tribute''

He opened by remarking that last week included Charles Darwin's birthday, and that he dedicated the evening to him as a "birthday tribute". Some time ago, Dawkins was working for a Japanese television company on a documentary, and as part of this they hired an actor to play Charles Darwin and had him knock on Dawkins's door. He would then be invited inside, and would be brought up to date on the latest advances of his theory of natural selection. It was, Dawkins agreed, a great honour for him to be chosen to update Darwin, albeit not the real man himself.

Darwin's dangerous idea, he continued, can lay a very good claim to be "the greatest idea ever to have occurred to a human mind". By explaining the enormous variety of life as we know it with a theory that can be stated in a single sentence, this was an extraordinarily audacious leap.

What would have happened if it had not been developed? Biology today would still exist, but very much as a discipline of study of individual organisms, with little understanding of their relationships to each other, and with their provenance still a mystery. We would undoubtedly know that organisms are composed of cells, and certainly what the functions of those cells are, but without an underlying unification of all forms of life biology would be considerably less rich and useful than it is now.

Darwin's idea of natural selection can be expressed succinctly as "the non-random survival of randomly varying self-replicating entities". Although one can never be 100% certain of anything, Dawkins opined that "We are now as certain as we can ever be in science that this idea is the correct one".

Dawkins then touches on one of his favourite analogies: that living organisms are survival machines for genes. Genes that build good survival machines propagate and multiply in the gene pool and out-compete other genes. Much of the more sophisticated versions of these machines are the result of "arms races" between competing species. This kind of positive feedback mechanism leads to such extremes of apparent design as the cheetah and the antelope.

Darwin Up to Date

How would Charles Darwin fare today? To a remarkable extent, he was right, with some notable exceptions. Darwin believed in the inheritance of acquired characteristics, a position championed by Lamarck and which now carries his name. This has since been demonstrated to be wrong, but was the conventional wisdom on inheritance at the time. Additionally, he believed that inherited characteristics blended together over the generations. At the time, Fleming Jenkin showed that this would make evolution unworkable, as the amount of variation would, on average, decrease by half each generation. This worried Darwin, and Jenkin seized upon it as a disproof of evolution by natural selection.

The problem was finally solved in the 1920s by Sir Ronald Fisher, who integrated natural selection with the work of Gregor Mendel. Mendel had discovered that inherited "characters" did not blend together, but stayed apart from one another, preserving variation from one generation to the next. Jenkin had indeed seized upon a disproof, but it was of blended inheritance, not evolution by natural selection.

Darwin actually devotes a chapter of On the Origin of Species to problems he perceived with his idea. Jenkins' claims is one of them, another was due to a calculation of the age of the Earth by Lord Kelvin. Kelvin was on of the foremost physicists of his day, and he calculated the maximum age of the sun on the assumption that it brought forth heat and light by the familiar process of burning. The sun, he claimed, could not be older than a million years, and the Earth therefore must be younger. Darwin realised that this severely limited the amount of diversity that could be expected to arise.

Again, it was not until the 20th century that the solution presented itself. The sun burns not through chemical fire, but by the immensely more energetic process of nuclear fusion. Currently, all the evidence points to a sun and Earth with an age greater than 4.5 billion years - ample time for the processes that Darwin recognised to create the immense diversity of life on our planet.

Darwin even anticipated the favourite problem of his detractors, the evolution of complex organs. In On the Origin of Species, he outlines the gradual evolution of the eye from a primitive light sensitive spot all the way up to modern camera-like eyes. Here, he points out, there is always a gradual gradient of function. Half an eye is better than a quarter of an eye, is better than no eye at all.

One particular line of attack rests on a phrase which originates not with Darwin himself, but with his colleague Wallace. "The survival of the fittest" seems like a tautology; the fittest are defined as those that survive, and this is the meat of the argument. However, language does not stay static. Our modern definition of biological fitness owes much to natural selection and the ability to survive. At the time the phrase was coined, however, "fitness" still carried the familiar physical connotation - fast, strong, healthy animals are what is being discussed.

Sexual Selection

Wallace once described himself as "more Darwinian than Darwin", and the two men disagreed on many points. One of these was the existence of sexual selection. In fact, 19th century views on sexual selection so shaped the basis of the subject that only recently has it re-emerged as a respectable hypothesis.

The problem can elegantly be explained with reference to the peacock's tail. The male peacock has a tail so larger that it is a clear hindrance in the everyday task of survival. How, then, can it have evolved? The suggestion was that it was shaped by female taste; those peacocks that had more attractive tails mated more often and produced more young who also carried the trait for large tails.

One of Darwin's contemporaries expressed his incredulity of this concept because he could see no reason for the females to continue to like long tails consistently for a long enough time for the effect to be noticeable. In fact, he said, since "permanence of female taste was scarcely verifiable in human affairs", why should we assume any different in animals.

Again, it was Sir Ronald Fisher who unravelled the puzzle. If the female preference itself is under genetic control, then it too can be inherited. The offspring of peacocks with large tails not only carry the gene from their father for large tails, but also the gene they inherited from their mother for liking large tails. A small amount of this kind of close genetic coupling can easily take off, leading, like compound interest, to an exponential growth in tails and the preference for them. This will eventually be checked by other pressures, but in a relatively short time, this kind of co-evolution can produce spectacular results.

An additional function has been suggested by Hamilton and others working in contemporary biology. Hamilton suggests that parasites might help to drive the sexual selection mechanism. (But, Dawkins mentions as an aside, Hamilton sees parasites as the answer to everything.) The impressive displays can be used by fussy females to judge the fitness of their suitors. Unhealthy males are unlikely to produce as colourful or expensive an array of advertisements as their healthy competitors. Even not trying is as damaging as producing a bad show; it implies they have something to hide. In this way, natural selection favours honest advertising from all males, even though only the healthy ones benefit.

Here, Dawkins wanders off the beaten track a little. Why, he asks, do humans not have a penis bone? ("It catches in zips" suggests one of the audience.) Our closest ape relatives do, so why not us? Since we have evolved an upright posture, the state of the penis is very visible. If erection failure is an early warning for any kind of ill health (and it is a known symptom of several diseases), then it would pay in evolutionary terms to make erection as obvious as possible. The extreme difference in posture of the erect and flaccid penis is enhanced by the loss of the penis bone, and its use as a sexually selective signal is also enhanced.

This, Dawkins admits, is highly speculative, but it does show how diverse traits can arise by natural selection.

Universal Darwin

To wrap up, it has been claimed that there were three truly great men of ideas in the 19th century - Darwin, Marx and Freud, but in conclusion Dawkins has something to say about this. Can these three ideas really be judged equal? He illustrates this by imagining the universal applicability of the three. If aliens from another galaxy made contact tomorrow, they would undoubtedly be far more advanced than us. Marx and Freud would probably be minority interests for their anthropologists.

Darwin's idea of evolution would be immediately familiar. They may be surprised that we have already discovered it, or they may be perplexed that it took us so long, but they would recognise it and have their own equivalent. Darwin has universal applicability.

Book Cover: River out of Eden

INTERVAL

After the interval, Dawkins returned to the stage for a question and answer session. First, though, he talked about the acceptance of evolution as an idea. It took a long time for one of us to realise it, and even 150 years after its first formulation, many people still do not grasp it, or indeed oppose it against all the evidence. Why is this?

The magnitude of the times and populations involved is the most difficult hurdle. Most simple principles can be demonstrated in the laboratory, but Darwin's evolutionary theory, even though it is simple to state, is not so simple to demonstrate and we must rely on other evidences. However, he reiterated, we are as certain as we ever can be that this is indeed what happens.

Questions and Answers

Why do we grow old?

Genes often turn on at specific stages in development. If a gene mutates to give a particular advantage early in life, but is potentially lethal later on, then it will not be selected against as long as it allows an organism to have more offspring. Thus, since there is little or no selection pressure against late-acting lethal mutations, they are not eliminated and the diseases of old age gradually catch up with us.

What is the future for human evolution, or have we stopped evolving?

Evolution is impossible to predict in detail. Generally, the pressures acting on us now are very different from those even a thousand years ago. It would seem, however, that we are selecting for one very specific attribute: incompetence in use of contraceptives.

Cultural evolution, with ideas or "memes" as replicators, has largely overtaken physical evolution as the main selective mechanism in that last few thousand years.

How did religious belief come about?

There are several suggestions for this. The first is based on observations that religious believers are slightly less likely to die of stress-related illness than non-believers. This may be due to less burden of worry and increased sense of community which comes from belonging to a group of like-minded individuals.

Secondly, the greater cohesion that common belief lends to a society may make it less vulnerable to attacks from other societies. In its most extreme cases, waging war against another culture is likely to be more successful if the combatants believe that there is an afterlife, and especially so if the afterlife is replete with available virgins, for instance.

A more insidious perception, and one Dawkins holds to a large degree, is that religions are self-replicating idea sets. These are the memetic equivalent of viruses, conveying no advantage to their hosts, but propagating in the same blind, pointless way as their genetic virus counterparts. The idea sets have a single purpose - to be copied into new hosts with high fidelity. Like other forms of replicator, once the primitive form comes about, evolution proceeds quickly and produces a fascinating set of inducements or lures. St. Paul's cathedral and much exquisite music are sophisticated "hooks" for instilling itself in new minds.

How does altruistic behaviour come about, such as contraception?

Since the evolutionary pressures acting on us at the moment are largely cultural, memetic pressures, we can view the widespread use of contraception as good for brains rather than the whole organism.

Social Darwinism also gives insight into supposed altruistic behaviour by looking at the effects of society on an individual. Highly social individuals may increase their own reproductive success more by contributing to the society than by being conventionally selfish.

Book Cover: The Blind Watchmaker

Why are we not well fitted to our modern environment?

Genetic evolution works over very long periods of time. The explosion of change over the last few thousand years means that many features have not yet had time to adapt to our new, largely urban environment. Take, for example, our willingness to help others. In the distant past, humans probably lived together in small bands. It was in your interests to be helpful for two reasons. Firstly, the people you were with were likely to be quite closely related to you. Secondly, you would be meeting them again and again during your life, and selfish behaviour may have more negative repercussions than helpful behaviour. This is a reiteration of the previous point.

Moths spiralling into candle flames is another classic example. The sudden appearance of close light sources at night confuses the moth's navigation systems which have evolved to take notice of distant light sources like the moon and stars. By flying at a constant angle to a distant light source, the moth can fly in a straight line, which is a useful thing to do. But translate this to a nearby light source and the moth will fly in circles or spiral into the light.

In both these cases, the environment has changed very rapidly, and evolution has not yet had time to select for organisms that can cope with the new status quo.

What is the relationship between Darwinism and eugenics?

Selection of particular individuals for particular characteristics can be done, and it does not require any kind of high technology. It has been done to dogs, for example, and domestic farm animals with spectacular effects. It can certainly be done with humans, but there are strong moral and ethical objections against it.

If Britain wished to win, say, all the Olympic high-jump medals in five hundred years time, then it would be a relatively simple matter (biologically speaking) to select successful high-jumpers and breed them together, producing better and better high jumpers at each generation. The social pressures against this kind of thing are immense, however, and it is extremely unlikely to happen.

Negative eugenics is already happening to a degree. Parents often go in for genetic counselling if they belong to families with histories of a particular disease, such as Huntington's. This is much less controversial, although it is easy to see that it too can become beyond the pale very quickly.

Where did the first DNA strand come from?

No-one really knows, but it was unlikely that DNA was the first self replicator; it is too large and fragile for that. Several competing theories exist, including the "RNA world" theory and others based on much simpler replicators. When conditions were right, DNA took over, presumably because it was more efficient in the new environment than the first replicators, and they effectively became subsumed or extinct.

In broad terms, we know that the first replicator must have been a relatively small, self-catalysing molecule, and a lot of research is going on in this direction. For now, we don't know.

''If the basis of mutation is random, and therefore mysterious, aren't the people who have a deep sense of religious mystery the real Darwinians? [This is a summary of a very long and rambling question, and Dawkins was obviously itching to answer.]

Not at all. The two things are completely different interpretations of the word "mystery". There is nothing mysterious about the mechanisms of mutation, but they are unpredictable. Religious mystery is a cognitive function of the brain. The two are completely unrelated and the question is therefore meaningless.

How long would female preference have to continue to make sexual selection effective?

It needs only to apply just long enough for the population to contain a critical number of individuals with the closely coupled feature/preference genes. After that, positive feedback takes over and the trait spreads throughout the population very quickly.

How do Grant's finches adapt their beak lengths over single generations?

The short answer is that this adaptability is selected for, although a full discussion would require a lot of mathematics and is beyond the scope of this talk.

Artificial life simulations often work without mutation. How important is it?''

There are other mechanisms than mutation available for genetic variation. In sexual animals, genes are randomly selected from the father and mother in a process known as crossover. Mutation is a much slower process, but serves to "top up" the variation in the gene pool.

Finale

At this point, Dawkins wrapped up the question and answer session, and the theatre's director thanked him on all our behalves for his interesting talk, and they both left the stage to the resulting applause.

See Also

First, I must refer you again to John Catalano's Website on Dawkins, an excellent repository of events, links, articles and news.

The complete text of Darwin's book On the Origin of Species is also available online.

Dawkins' books themselves are also required reading: