This is the book Richard Dawkins needed to write and many need to read ... clear, absorbing and vivid. - Lord Harries of Pentregarth (formerly Bishop Richard Harries).
With characteristic flair and passion, Dawkins has put on a stunning exhibition of the evidence for evolution. - Dr Alice Roberts, Biological anthropologist, author & broadcaster
Whether it’s Lenski’s bacteria or our own ancestors, Richard Dawkins discusses the evidence for evolution with his usual charm, style, clarity and brilliance. - Simon Singh, author of Fermat’s Last Theorem
From the Author
“Darling, I’d like you to meet my partner, Mr Gabbitas. Mr Gabbitas, this is my partner, Sophie. We have a green car, a low carbon-footprint hybrid-electric, but it isn’t green, it is a much more gay colour than that.”
We all have to get used to sorting out words like ‘partner’ or ‘green’ or ‘gay’ that have two meanings, and use them without confusing ourselves or each other. We usually manage it fine. Except, apparently, in the case of ‘theory’ – and you have to wonder how sincere the confusion is. In everyday language, theory can mean “hypothesis that might be right and might be wrong”, as in “It’s only a theory.” Alternatively, theory can mean, in the words of the Oxford Dictionary, “a statement of what are held to be the general laws, principles, or causes of something known or observed.” Scientists use the second meaning, as in the Cell Theory of living bodies, the Atomic Theory of matter, or the Helioentric Theory of the Planets. Evolution is a first class Theory in this second sense. It embodies the general laws or principles of the history and distribution of life. In the everyday, common-usage sense of ‘fact’, evolution is a fact. It is a fact that we are cousins of chimpanzees, giraffes, mushrooms and pomegranates: we share a common ancestor with all of them. Evolution is not an article of faith. Evolution is a massively and repeatedly demonstrated fact. It is no more an article of faith than your belief that the Earth spins on its axis and orbits the sun. The Greatest Show on Earth is my explanation of the welter of powerful evidence that evolution is a fact.
What are some of the examples of evolutionary change happening before our eyes?
Most of evolutionary change takes place too slowly for us to see, because we don’t live long enough, either as individuals or even as a culture. We are like fleas trying to see the hour hand move on a watch. Mostly, the best we can do – like detectives coming on the scene of a crime too late to witness it directly – is look at the clues that remain after evolution has happened, of which there are plenty, and such evidence dominates my book. But evolution does occasionally go very fast, sometimes so fast that we can see it ‘Before our Very Eyes’ – which is in quotes because it is the title of one of my chapters. A large-scale analysis of the shooting records of elephant hunters in Uganda shows that average tusk size became progressively smaller, from 1925 to 1958, at a steady rate of about 200 grams per year. This is probably because of natural selection: hunters are after ivory, so they pick out the largest tuskers.
Even faster is the evolution of antibiotic resistance in bacteria, which has happened again and again, with antibiotic after antibiotic, ever since Florey and Chain first introduced penicillin in 1939. My book expounds the research of the American biologist Richard Lenski, who exploited the speed with which bacteria evolve in a splendid experimental study continued over more than 20 years and more than 45,000 bacterial generations. A striking coup of Lenski’s method is that he can freeze bacteria for an indefinite period, then thaw them out whereupon they resume life – and evolution – as if nothing had happened. This means that Lenski can lay down his own ‘fossils’ at any point during the evolutionary process, and then revive (literally living) ‘living fossils’. I also describe the work of the American zoologist John Endler on the rapid evolution of male guppies in Trinidad, during a span of only eleven years after they were transplanted to a new stream. This stream, unlike the fishes’ natal stream, had no predators, and the guppies were consequently freed up to abandon their dull camouflage and evolve rainbow colours to attract females.
Why doesn’t the fossil record contain a fronkey, or a crocoduck?
The question betrays a lamentable confusion about what evolution means. Yet such questions really have been truculently asked, in all earnestness, by creationists: for example the Australian creationist John Mackay, who is regularly invited to preach to British schoolchildren, and the Turkish creationist Harun Yahya, whose giant, coffee-table-sized, lavishly illustrated books are distributed free (where does the money come from?) all around the world in dozens of languages. The question presumes that evolutionists ought to find an intermediate between pairs of modern animals, such as frog and monkey, or crocodile and duck. Since the pairs of animals are arbitrarily chosen, there is no more reason to expect a fronkey or a crocoduck than a hippopotoroo or a kangaroach or a chimpanzoceros. Do these people really, seriously, truly and honestly believe that that is what evolution is all about? Doesn’t it occur to them that, if it were really like that, there would have to be a fossilized intermediate between every modern species and every other modern species? Two million species have so far been described (a considerable underestimate of the total number of living species) yet those 2 million would generate 4 trillion pairwise combinations. Every one of those 4 trillion should, according to MacKay’s and Yahya’s misunderstanding of evolution, have left a fossil. When you put it like that, you can immediately see what a ridiculous expectation the fronkey is. It is hard to see it as anything other than a dishonest attempt to bamboozle the ignorant.
Instead of some monstrous chimera, half way between a monkey and a frog, the fossil we might reasonably seek is their common ancestor, which is no more intermediate between a frog and a monkey than it is intermediate between any amphibian and any mammal. For the same individual is the common ancestor of all amphibians and all mammals. It probably looked a bit like a salamander (certainly not remotely like a frog or a monkey) and it lived about 340 million years ago. Unfortunately, it is not particularly likely that we shall find the very fossil that is the ancestor of all amphibians and all mammals, but we can hope to find fossils that are reasonably close cousins of that ancestor from around the right period. And find them we do.
In any case, an ancestral fossil is not particularly likely to look like an intermediate between its modern descendants. The title of intermediate is better conferred on fossils that are genuinely intermediate between older fossils and younger fossils or modern creatures. For example, we expect to find (and do find) fossils that are intermediate between older marine fish and younger land-dwelling amphibians. These are interesting because they illustrate the transition from water to land. Showing the later, reverse transition, we have fossils that are intermediate between older land dwelling mammals and younger whales. Between early fossil horses such as Hyracotherium and modern horses, we find fossils such as Mesohippus that are intermediate, both in size and in the trend to reduce the number of toes to the single (middle) toe that bears today’s hoof. And, following Darwin’s insightful prediction, Africa has yielded numerous fossils that are intermediate between ape-like ancestral hominids and modern humans.
The fossil record is replete with fascinating intermediates, and my book discusses several of them, but nevertheless there are, of course, some gaps, waiting to be filled. What there is not is even a single fossil in the wrong place in the evolutionary time sequence. Not a single example of the legendary ‘fossil rabbit in the Precambrian’ which, if it were ever found, would blow evolution out of the water. Evolution is extremely vulnerable to disproof, yet has never been disproved.
Is there anything about evolution that we still don’t understand?
Yes, plenty. We don’t fully understand the evolution of sexual reproduction or subjective consciousness. Nor do we fully understand the origin of the DNA code. But the beauty of science is that we know what we don’t know and we keep working at it. Science raises questions that need answering, we have methods for answering them, and we usually succeed if we work hard enough. This really is a big difference from creationism (often disguised as Intelligent Design ‘Theory’) which has no methods of any kind for answering questions, and whose only answer, to all questions, is the lazy and empty “Goddidit”.
From the Inside Flap
Charles Darwin's masterpiece On the Origin of Species shook society to its core on publication in 1859. Darwin was only too aware of the storm his theory of evolution would provoke. But he would surely have raised an incredulous eyebrow at the controversy still raging a century and a half later. Evolution is accepted as scientific fact by all reputable scientists and indeed theologians, yet millions of people continue to question its veracity.
In The Greatest Show on Earth Richard Dawkins takes on creationists, including followers of 'Intelligent Design' and all those who question the fact of evolution through natural selection.In this brilliant tour de force he pulls together the incontrovertible evidence that underpins it. Like a detective arriving on the scene of a crime, he sifts through fascinating layers of scientific facts and disciplines to build a cast-iron case: from the living examples of natural selection around us in birds and insects; the 'time clocks' of trees and radioactive dating that calibrate a timescale for evolution; the fossil record and the traces of our earliest ancestors; to confirmation from molecular biology and genetics.All of this, and much more, bears witness to the truth of evolution.
The Greatest Show on Earth comes at a critical time: systematic opposition to the truth of evolution is now flourishing as never before, especially in America. In Britain and elsewhere in the worldteachers witness insidious attempts to undermine the status of science in their classrooms. Richard Dawkins provides unequivocal evidence that boldly and comprehensively rebuts such nonsense.At the same time he shares with us his palpable love of the natural world and the essential role that science plays in its interpretation. Written with elegance, wit and passion, it is hard-hitting, absorbing and totally convincing.