http://www.digitaljournal.com/article/283307

Op-Ed: The greatest show on earth - the evidence for evolution

Posted Dec 11, 2009 by Bart B. Van Bockstaele
Religionists often claim that there is no evidence for Darwin's theory of evolution. World-famous biologist and author Richard Dawkins takes them on and shows how wrong this claim is.
Cover of Richard Dawkins  book  The greatest show on earth: the evidence for evolution
Cover of Richard Dawkins' book "The greatest show on earth: the evidence for evolution"
Richard Dawkins
Richard Dawkins is a biologist. I am a computer programmer. While these two disciplines may seem terribly different, they really aren't. In fact, they are very similar, even exactly the same thing in some ways: biology and computer programming are both about the creation of programmes.
An important difference between biological programmes and computer programmes is that computer programmes are artificially designed by (somewhat) intelligent beings, while biological programmes have evolved as the result of random changes that are naturally selected in a non-random fashion, i.e. while computer programmes are planned, biological programmes are unplanned.
Because of the similarities and the differences between the two fields, the Darwinian theory of evolution seems as plain to me as Newton's laws of motion. Add to that a lifetime of interest in biology and other sciences and the conclusion is self evident: I view the theory of evolution as a fact that is just as plain and solid as the heliocentric theory of our solar system.
On top of that, I am also a European, and for most Europeans, the theory of evolution is one of those facts of life only a scientific pervert would ever doubt, since it is a basic part of biology lessons in most European schools, regardless of religion. The Vatican, while certainly less than thrilled with evolutionary theory, has largely accepted it, and it is taught in most, probably all, Catholic schools. My own father, once a Trappist monk (often regarded as the most extremist of the monastic orders in Christianity), never doubted evolution, and he found great beauty and elegance in it, and he did so, even during his more fanatical days.
Years ago, when I saw Richard Dawkins explain in documentaries and lectures that Americans often do not accept the theory of evolution, I thought that this was simply a cheap bit of American-bashing -a popular sport in Europe- nothing more.
When I came to North America however, I had to learn to accept that the US is indeed not unlike Saudi Arabia, a country that is at least partly governed by religious fanatics who doggedly try to stifle scientific progress and to destroy the personal wellbeing of all citizens, not just the followers.
In other words, had I stayed in Europe, I would have viewed Richard Dawkins' latest book "The greatest show on earth: the evidence of evolution" as of little interest to me, and I would most probably not have read it. But I am not in Europe, so I did in fact read it, and I am glad I did.
The book starts by explaining what a scientific theory is. While the word "theory" is akin to "guess" or "speculation" in daily language, it has a very different meaning in the sciences, where a theory is a system of ideas that attempts to explain a group of facts or observed phenomena.
Dawkins makes a distinction between the fact of evolution (all living things are related to each other) and the theory of what drives it (natural selection). He points out that no scientist doubts the former, but that there is still some room for doubting that natural selection is the main driving force, albeit only just.
In the second chapter, aptly named "Dogs, cows and cabbages," Richard Dawkins shows that much of the resistance against evolution comes from Plato and his friends, now known as the essentialists. They saw the differences within one species as mere variations on a theme, imperfect projections of an essential form. As Dawkins decribes it:
The Platonist regards any change in rabbits as a messy departure from the essential rabbit, and there will always be resistance to change – as if all real rabbits were tethered by an invisible elastic cord to the Essential Rabbit in the Sky.
"The evolutionary view of life is radically opposite," he says, and he gives the example of an unbroken line of rabbits, slowly, imperceptibly, but nevertheless definitely changing, changes that are for the most part unseen when jumping from generation to generation, but that are clearly seen when looking at the entire line. This way, a shrew-like animal can change into a leopard, thanks to changes that are too minute to discern.
Prof. Dawkins introduces the elegant idea of the hairpin-bend: since all creatures are related, one can trace back from any currently living thing to a certain point in the past (where the bend occurs), and then trace back up to reach the other currently living thing, all by following minute changes.
He does this to show that the creationist idea that crocodiles can change into ducks is ridiculous. Both are modern animals, and while they are related to each other, it is not because one became the other, but rather because they share a common ancestor.
The story then goes on to show how artificial selection, the laboratory equivalent of natural selection, can transform an original species into wildly different variations, some of which can be rightly called different species by some definitions.
In the following chapter, "The primrose path to macro-evolution," Dawkins shows how natural selection and artificial selection or domestication can produce similar results. He tells us, for example, that insects were the first domesticators, and shows how flowers are bribing insects into having sex for them.
This is, in some ways, a reference to his scientifically most important book, "The extended phenotype," where he argued very convincingly (so convincingly in fact, that one would be hard-pressed to find a biologist who doesn't buy into the idea) that genes do not only shape the bodies in which they reside, but also elements of the world in which these bodies evolve, regardless of whether these elements are inorganic or organic.
That these considerations are not "merely a theory" as everyday speech would call it, but a genuine theory in the scientific sense, is illustrated by its predictive powers.
An impressive example of this is Darwin and Wallace's prediction that moths would be discovered with unbelievably long probosces, purely on the basis of the existence of orchids (Angraecum sesquipedale) with very long tubular nectar holders. The moth (Xanthopan morgani praedicta) wasn't discovered until 1903, after Darwin's death, and it was rightly given the subspecies name of praedicta ("predicted").
Prof. Dawkins then shows how natural selection does not need an intelligence in order to function by giving a progression, from deliberate to accidental:
1. Humans are able to change wolves into chihuahuas and to stretch maize cobs from inches to feet by selecting the individuals they like best. This is a deliberate process.
2. Peahens create spectacular peacocks by choosing the most attractive ones to breed with. This may or may not be deliberate, but probably is not.
3. Small preyfish create efficient anglerfish by "choosing" to be eaten by the most attractive ones. This is most definitely not a deliberate process, but the preyfish do still use their eyes to make their selection.
4. Hunting fish like tuna or tarpon are being selected simply by being more efficient at pursuing and catching prey, regardless of the reason: keen eyes, strong swimming muscles...
Dawkins goes on to show how artificial selection can change species in spectacularly short amounts of time, by quoting a few well-known experiments about the artificial selection of maize for oil, rats for tooth decay and foxes for tameness. Humans have a ridiculously short lifespan in comparison to geological and evolutionary time and yet, these changes can often be brought about within a single human lifetime.
It does not take much imagination that if humans can create spectacular changes in a species within a matter of decades, natural selection can do even more in time stretches that defy our imagination, such as the two million centuries separating our own species from the origin of mammals.
In chapter 4, "Silence and slow time," we are shown how we know that evolution has taken as long as it has, namely billions of years, and that the creationist idea of a young earth less than ten thousand years old is simply untenable and beyond any serious contemplation.
Dendrochronology is a science that measures time by studying the life cycles of trees, in essence by counting tree rings. Dendrochronology can measure time to within one year. While most trees do not live more than a few centuries, overlap between trees can be used to create an uninterrupted scale that goes back much further. Unfortunately, current gaps in the fossil record limit the usefulness of this attractive time measuring method. We can go back approximately 11,500 years, but no more. Nevertheless, this already destroys the time scale of many young earth creationists, by simply doubling it.
Radioactive clocks take us back much further. This is done by measuring the decay of radioactive elements. They enable us to measure time in centuries to billions of years. These clocks are less precise than dendrochronology, usually to within about 1%. Radioactive dating is not a biological science but an element of physics, a nice example of how different scientific disciplines are working together to help us understand the wonders of the natural world.
Professor Dawkins then goes on to show how radioactive clocks and geology can be used together to estimate the age of fossils. En passant, he shows how the flood theory preached by many creationists is untenable, unable to explain what we actually see in the fossil record.
Creationists often claim that the theory of evolution is merely a belief, because we don't see it happening. In chapter 5, "Before our very eyes," Richard Dawkins shows us -once again- how wrong they are. It speaks for itself that a single human cannot observe the complete history of a phenomenon that takes countless human lifespans, but that doesn't mean it didn't happen.
Using the metaphor of the detective who must reconstruct a crime, Professor Dawkins shows that this is no reason for thinking that we cannot know what happened and he also shows that we are able to witness evolution by natural selection within a single human lifespan, given the right conditions. We are shown such diverse examples as the tusk length of elephants in Uganda, insectivorous lizards turned vegetarian on the island of Pod Mrcaru, Richard Lenski's long-term experiment with Escherichia coli (a much reviled bacterium of nevertheless fundamental importance for our survival), and guppies studied by Reznick and Endler.
Chapter 6, 'Missing link? What do you mean, "Missing'?," is probably the most hilarious chapter of the book. Creationists are fond of what they have been told are unexisting "transitional forms" and "gaps" in the fossil record. The fun part here is that the more complete the fossil record is becoming, the more gaps they are seeing.
Imagine a court case, where the jury and the judge would become less convinced when there is more evidence. That would mean that, the more evidence there is pointing at the murderer, the more chances this murderer would have to go free. Yet, this "Alice in Wonderland" style of unreason is exactly what the creationists practice.
Looking at the fossils of two related species, the creationist will demand to be shown the "missing link" or "transitional form" because there is a "gap" between the two. When such a transitional form is discovered, the creatonist is elated, for there is now not one "gap" but two, namely one between the first fossil and the new discovery and one between the new discovery and the second one. Every time a new transitional form is discovered, one "gap" becomes two "gaps". In other words, science can't win, in the distorted mind of the creationist.
Science has given the creationists a fantastic method to disprove evolution. All they have to do, is to discover a single species in a geological stratum where it does not belong, according to evolution theory. To quote J.B.S. Haldane's famous example: fossil rabbits in the Precambrian would simply destroy the theory. Yet, no creationist has ever found such an example.
Professor Dawkins then takes on some of the most popular non-arguments used by creationists to discredit evolutionary theory. Two of the finest examples of this are the fronkey, a supposedly missing link between frogs and monkeys, and the crocoduck, an imaginary missing link between crocodiles and ducks.
All this does, is showing a painfully and ridiculously warped understanding of evolution: modern animals do not evolve into each other, they evolve from common ancestors. Frogs and monkeys cannot possibly change into each other, but they most certainly have a common ancestor that would be not much like a frog and nothing like a monkey either.
Chapter 7, "Missing persons? Missing no longer," talks about the descent of man, by quoting one of the more enigmatic phrases of Darwin's Origin:
Light will be thrown on the origin of man and his history.
In this chapter, Richard gives us a fascinating overview of what is now known about our own origins, and he quotes an interview with Wendy Wright, President of "Concerned Women for America," that he had conducted for his documentary "The Genius of Charles Darwin". This interview is astonishing, a fine demonstration of the exquisite reasoning powers of many creationists. As Dawkins puts it:
Her opinion that ‘The morning-after pill is a pedophile’s best friend’ gives a fair idea of her powers of reasoning, and she fully lived up to expectation during our interview.This is a must-read if you're in the market for a good belly-laugh that'll make your toes curl. It nicely shows why biologists usually avoid "discussing" with creationists: there is no point. No sane person tries to explain calculus to parsnips, so why bother discussing evolutionary theory with creationists? It is advice I'd do well to heed.
Chapter 8, "You did it yourself in nine months," is about embryology. Dawkins quotes an incident during which J.B.S. Haldane was told by some that it was hard to believe that complicated humans would result from the development of a single cell, to which he wittily replied:
But madam, you did it yourself. And it only took you nine months.
We are shown that the idea that our DNA is the "blueprint" for the human body is wrong, even though most biology textbooks say exactly that. Our DNA is not a blueprint, rather, it is more akin to a recipe or a computer programme, governed by local rules.
In Chapter 9, "The ark of the continents," we are shown what biologists mean when they use the word 'island', and Dawkins then goes on showing why islands are so important for the evolution and diversity of species. The Galapagos, made famous by Darwin, are -of course- discussed, and so are other interesting islands, such as Australia.
Plate tectonics are explained as well, for they too -by creating continents and islands- helped many species to evolve. Richard Dawkins wonders about the creationists' way of thinking, seeing that they seem to accept plate tectonics and the fact that Africa once was part of South America, all while denying the very evolution that this has allowed to happen. Why then, muses Dawkins, don't they go all the way, and deny plate tectonics as well?
Dawkins quotes Jerry Coyne, author of "Why evolution is true":
‘The biogeographic evidence for evolution is now so powerful that I have never seen a creationist book, article, or lecture that has tried to refute it. Creationists simply pretend that the evidence doesn’t exist.’
In Chapter 10, "The tree of cousinship," we are taken for a round of comparative anatomy. Since I have studied comparative anatomy in some depth a few decades ago, it is one of the chapters that I feel connected to. Dawkins shows here how mammals all have the same basic structure.
A human skull is compared to a horse skull, and it can clearly be seen that all the bones are there. Yes, they have different shapes, but they are there. We are shown how the okapi skeleton is similar to that of a giraffe. Dawkins goes on, trotting out example after example after example to show how comparative anatomy is a powerful argument for evolution, while noting that this too, is a field that creationists tend to ignore to the fullest.
The chapter finishes by talking about a field that Charles Darwin knew nothing about because it did not yet exist in his time: molecular biology. Molecular biology could therefore easily have utterly demolished the theory of evolution. But it did not. Molecular biology has confirmed and deepened evolutionary theory. In fact, molecular biology has become so refined that we can now talk about a molecular "clock" which can help us figure out when species diverted from their common ancestor, and much more.
Chapter 11, "History written all over us," we return to comparative anatomy, but with a twist. The chapter looks at how living things contain countless oddities that can only be explained by purposeless natural evolution or, if one really wants to attribute them to a "designer," by a blundering utter idiot. I'm quoting just a few examples.
The human eye, a creationist favourite, is a prime of example of unintelligent design as it contains just about every single flaw one could think of, such as the fact that our retina is pointed backwards: the photosensitive cells are pointed towards the brain, not towards the light they must capture. As a result, the nerves that transport the signals of the retina to the brain, form a carpet partially blocking light from reaching the photosensitive part. Worse still, in order to get the signal to the brain, this carpet of wires is amassed in a bundle that goes to the brain through a hole in the retina, resulting in a comparatively massive blind spot. Sounds awful? It's worse.
The laryngeal nerve is a nerve that splits off from the vagus nerve, a nerve bundle that comes straight from the brain, instead of going through the spinal column first. One part of this nerve goes straight to the larynx (voice box), but the second part makes an astonishing detour. It goes right down into the chest, loops around one of the main arteries of the heart and goes back up to finally reach the larynx. Design-wise, this is about as disgraceful as things come. In the human, the detour is inches. In the giraffe, however, the same detour is one of more than 10 feet.
While human embryos develop, they start developing gills, just like fish.Other than in fish, however, the gills never fully develop, they disappear instead, and as a result, humans do not have gills. What useless waste of energy! Worse, the same phenomenon can be seen in whales and manatees. These animals would be wonderfully well served by gills, but they don't have them, and they have to return to the surface rather frequently, for they would drown if they didn't.
Chapter 12, "Arms races and 'evolutionary theory'" describes how many phenomena can only be satisfactorily explained by arms races. Professor Dawkins gives the example of a forest where species of trees grow higher and higher, trying to catch as much sunlight as possible. Wouldn't it be better, if the trees held a peace conference, during which they all solemnly agreed to grow no higher than 10 feet? Think of all the energy that would be saved, and that could then go into other more interesting endeavours.
Now, just imagine that such an agreement was reached and that trees obeyed it. Sooner, rather than later, one tree would understand that it can now profit tremendously from the goodness of the others by growing higher. This in turn would once again lead to an arms race in which all trees are trying to outcompete each other.
We see the same thing between hunters and prey. While the leopard is a wonderful machine for catching gazelles, the gazelle is a wonderful machine for evading leopards. Over time, gazelles become better and better at evading leopards, all while leopards are becoming better and better at catching gazelles.
If these things have been designed by a designer, as the creationists claim, one can't help but wonder whose side this designer is on? But then, maybe some designer really did design everything, and he/she/it merely sadistically enjoys the terrible suffering that comes with these arms races.
"Nature" is an unthinking result of unthinking processes. This is perfectly compatible with everything we see. How does the hypothesis of a kind and benevolent designer explain the pointless suffering caused by viruses, for example? It does not. Evolution by natural selection does.
The last chapter of the book, "There is grandeur in this view of life," quotes one of the most lyrical paragraphs Darwin has written and in which he reveals himself as a true poet:
Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved. Richard uses this paragraph to contemplate some more or less random thoughts with respect to evolution, evolvability and the origin of life.
The book contains an interesting appendix, called "The history-deniers," an obvious reference to holocaust-deniers. In this chapter, we find depressing data on how many people are still denying evolutionary theory, and on how students are sometimes brainwashed by their keepers to sabotage biology lessons.
Conclusion
This book is written in Richard Dawkins' usual style: elegant and eloquent, as simple as possible but not any simpler than that, and with plenty of references to reliable sources and further information. I have enjoyed it tremendously, and while it has refreshed my memory on certain subjects, it has also given me an example or two I had not heard of before, such as that of the giraffe's laryngeal nerve and the strange pouch of the koala.
Will this book convince creationists? I hope so, but I have my doubts. The problem is that this book makes everything as simple as possible, but not more than that. In other words, Richard Dawkins' passion for dispassionate truth prevents him from writing in ways that most creationists can understand. In order to understand this book, some education and openness of mind is required, two properties creationists do not usually have in abundance.
I am guessing that the book will be convincing to a small group of creationists who just happen to already doubt the creationist story because of its perverse lack of coherence, and who have not been indoctrinated as badly as many others.
I am unsure of this, but I hope so. Even a small decrease of the number of creationists could lead to an increase of the quality of life of all people living in countries stifled by religious dogma, such as Turkey or the United States, and even if it does not immediately do so, it should have the effect of drastically improving the lives of those creationists who finally wake up from their ignorant slumber, and it would make life a little easier for those people who do not buy into religious fantasy.
For the rest of us, this book will give us some light, entertaining and informative reading, full of wonder and mystery, so much more interesting and rewarding a pastime than reading shallow fiction or watching Oprah on the boob tube.
In short, this is a book worth having and worth reading. More than once. Even if you've had a true education.