 A Summary of The Greatest Show on Earth The Greatest Show on Earth (2009) This is a discussion of selected parts of the book Page 9. Dawkins goes through the old issue of what is a theory and what is a fact. He explains how the word "theory" has a different meaning in science to what it does in more common usage. He explains how nothing is ever proven 100% in science but some conclusions are supported by such an overwhelming amount of data that it is reasonable to call them a fact. Evolution is supported by a huge amount of evidence from completely independent sources. There is no scientific alternative and its reasonable to call it a fact (although strictly speaking all facts are open to re-interpretation if new evidence is found). Page 88. Having sufficient time for processes to operate is essential to evolution so Dawkins presents the evidence of how several different, independent dating systems can be used to date fossils and other evidence beyond reasonable doubt. He discusses dendrochronology (dating using tree rings), varves, and radiometric dating. Page 97. There's a nice explanation here of the processes which allow dating of rocks back to billions of years using Potassium Argon dating. Page 99. A simple explanation of how the order of events can be established by dating layers of rocks and how these are consistent around the world. Also an explanation of how apparent anomalies in layering occur. Page 102. Includes a list of half-lives of some radioactive isotopes showing how one technique can be used to perform dating over an extremely wide range of time periods, from hundreds to tens of billions of years. Page 107. Dawkins isn't afraid to ridicule the pathetic concept that the world is only 6000 years old. He is often criticised for his open derision of people who believe in ridiculous religious ideas but I think its entirely appropriate in this case and is far more correct and considered in the Greatest Show than in the God Delusion. Page 114. Cites an example of evolution happening on a short timescale. Evolution deniers often criticise it because most of the evidence is from the (sometimes distant) past but this clearly shows the process is going on today and at a surprising speed. Page 117. Describes the amazing results from the Lenski experiment involving observation of evolution in E. coli. Several pages are spent explaining the significance of this brilliant experiment. Shows how significant change involving many genes occurred in a carefully observed environment. Another example of watching evolution actually happening. Page 171. Briefly mentions the fossil evidence demonstrating whale evolution. In recent years this has become an excellent demonstration of new species forming in exactly the way expected by evolutionary theory. The creationists defense against this is very unconvincing consisting mainly of picking small (and usually irrelevant) holes in the evidence that any reasonable person would accept. Page 174. Mentions a new fossil which seems to be an intermediate step in turtle evolution. Previously creationists have asked what use half a shell is. The danger (for them) in doing this is that they look stupid (or even more stupid than they already do) when an example if exactly that is found! The fact that this was discovered just as the book was nearing completion also shows the rate at rich intermediate fossils are being found. By the time the creationists have tried to discredit one fossil another one (or more) has been discovered! Page 180 (Postscript). Mentions a new fossil discovery made while the book was in its final stages. Emphasises how often new fossils demonstrating intermediate forms are found. Page 194. Makes the point that the apparent confusion in hominid naming (which is often incorrectly used by creationists to show uncertainty of the origin of the specimen) is actually what we would expect if evolution was happening. If a specimen is intermediate between two existing species of genuses then its obviously going to be difficult to say which it belongs to. This uncertainty is a natural consequence of the evolutionary process! Page 197. Discusses the numerous intermediate forms discovered in human evolution, especially a fossil of Homo ergaster which is almost complete (contrary to creationist claims that evolutionary conclusions are based on small bone fragments and a lot of guessing). Page 243. Discusses how embryonic development proceeds base don genetic information. Goes into detail regarding how the development of cells in C. elegans was discovered. Page 246. Elaborates on the process which occurs during development from one cell to a complete organism. Its based on asymmetric cell division and is well understood in some simple species. Its purely mechanistic and there is nothing mysterious or magical about it, contrary to the beliefs of many creationists. Page 288. Points out how all mammalian skeletons are essentially the same. the human hand and the bat wing are composed of essentially the same bones but changed in proportion. This is exactly what evolution predicts but makes no sense if the two species originated by creation. Page 297. Dismisses the idea that some creationists use by showing that the concept of the designed borrowing body parts from one species to use in another makes no sense. Page 322. Demonstrates how evolution is supported by an independent, statistical study. Researchers calculated theoretical family trees based on the similarity of 5 genes in 11 species. The result indicated a match close to what would be expected through if there was a genuine family tree. This is important because its hows how evolution could be disproved. If the trees calculated for the 5 genes were different then evolution couldn't have been the cause. If the species were independently created then we would expect no correlation between the trees. Of course, its possible to say the similarities are due to the process the god used to create the species but that's just relying on magic. In that case any result would support creationism because it makes no predictions. That's why it isn't science and has no intellectual credibility. Page 333. Describes how neutral mutations can be used to date changes using molecular genetic techniques. Identical changes (which are not susceptible to evolutionary pressure) in two species imply that those species split from an earlier form where the original mutation occurred. Page 340. Discusses vestigial structures where the current function has become useless, minimally function, or has changed during evolution. Lists the differences between the dolphin (a mammal) and the dorado (a fish) which are superficially similar but have evolved through different processes (the dolphin evolved from a land animal). Its difficult to see why a creator would create an aquatic animal like a dolphin with lungs where it could potentially drown when there was already a more appropriate mechanism used in fish (gills). Its possible to say something like "god wanted diversity in the way his creatures lived" but again that's invoking magic and has no credibility. Using that argument anything is possible. On the other hand, the dolphin body fits perfectly with the specific predictions of evolution. Page 351. Lists some species which have lost their eyes because they live in caves which are constantly dark. One of the best examples is the cave salamander. If this animal had been created to live in caves why give it non-functional eyes? If it needed the ability to see why not give it eyes which work? It makes no sense from a creationist perspective but its exactly what would be expected from an evolutionary perspective. Page 354. Creationists often claim that the intricate and perfect machinery of life could never arise by chance. (Of course, evolution doesn't claim they do arise entirely by chance so that's another typical creationist straw man argument). If life is so perfect why are there so many examples of bad design? The example of the human eye is given. Because of its evolutionary history it has a terrible design where the nerves block light from reaching the retina. There is also a blind spot where the nerves pass back to the brain. Any competent designer would take the nerves through the back of the eye. Yet again this makes no sense if the eye was the work of a perfect creator but fits in with what evolution predicts. Page 356. Another example of bad design is given: the laryngeal nerve. This nerve takes a bizarre detour before reaching its ultimate destination. If current mammals had a fish-like ancestor this would make sense but it makes none at all if it had been designed. Page 363. The extreme example of the laryngeal nerve is in the giraffe. It detours past the larynx (its eventual destination) all the way down the neck and back up again. This only makes sense if the giraffe evolved over a long period of time where each small change to the length of its neck resulted in no major disadvantage yet now the flaw in the path of the nerve is obvious. Page 365. Discusses an obvious flaw in human anatomy: the path of the vas deferens. No designer would create such a flawed path but it makes total sense when gradual change over a long time period is considered instead. Page 369. If god designed the human back he surely did a terrible job. Is this really the work of a perfect creator or of a change from a horizontal to a vertical (upright) stance over millions of years of evolution. The logical answer is obvious. Page 370. There are so many examples of bad design in all species (humans are one of the worst) that a whole book could be written on that alone. Another example is mentioned: the sinuses in humans which drain from the top. Why would they if they humans hadn't evolved from quadrupeds where the drains would then be at the front. There really are only be two possible rational conclusions: either god is terribly incompetent (I don't think creationists would be happy with this idea) and did a hopeless job in designing his creations or he didn't design them and a less well guided process (like evolution) did. Page 376. Discusses how complex structures evolved by taking over existing functions in other organisms. Chloroplasts (the "energy factory" in plants) originated as green bacteria which invaded plants and were assimilated into the plant. They still reproduce independently of the plant in a way similar to other bacteria which (again) fits evolution perfectly but makes no sense if the plant was designed. Page 380. Presents the evidence for an evolutionary "arms race" where competing species evolve in response to each other. Trees growing taller to out-compete other in a forest and the competition between predator and prey are given as examples. This competition and change is the essence of natural selection which is the most important evolutionary mechanism. Page 389. Describes how evolutionary competition is inevitable because any new attribute produced as the result of a mutation and which results in a competitive advantage will be selected for, even in an environment which was previously working in a "balanced" state. Page 391. Points out how the incredible suffering and futility of the natural world fits in with evolution but makes no sense as the creation of a caring god. If an animal suffers as it is killed and eaten by a predator it makes no difference to evolution because that animal's genes won't be passed on anyway. But why would God allow that to happen unnecessarily? Page 402. Points out that many of the consequences of evolution are unpleasant but that makes no difference to how likely it is to be true. The logical fallacy argumentum ad consequentiam is often used by religious people. They dislike the consequences of evolution so they reject it. The correct response is to accept the facts of the natural world but not use those same mechanisms in human culture. Page 404. Mentions how Darwin partly gave way to religious pressure in later versions of On the Origin of Species but probably didn't believe these compromises himself. Page 421. Abiogenesis (the origin of life) isn't strictly part of evolution but Dawkins discusses the "RNA World" theory as a likely process. While the exact origin of life isn't known that doesn't really weaken evolution which deals with changes in different forms of life once it did arise. Page 436. Describes some examples of the deliberate propaganda and lies being spread by religious organisations and how many of these are tax exempt organisations yet what they are doing is contrary to the public good. The problem is most obvious with fundamentalist Christianity in the US, but is becoming more prominent in Britain and Europe, especially with fundamentalist Islam, which in many ways is even worse. Summary Nothing in the book by itself proves that evolution is true and that creationism can't be true but the only way to believe creationism is to accept a huge number of extremely artificial and unlikely theories which have no credibility because they are unfalsifiable. For example, the poor design of the human eye is a natural consequence of its evolution from early, more primitive forms. But creationists might explain it with ideas like: "the eye works so its good enough", or "the eye used to be perfect but since the Fall it has become imperfect like anything else", or even "we aren't capable of understanding the full subtlety of God's design". The problem with these explanations is that they can be used to explain anything however ridiculous. If the eye was perfect creationists would say god obviously created it. If it has obvious deficiencies that also is forced to fit in with a religious view. Creationism makes no predictions about anything because creationists just keep changing the rules as new evidence arises. That sort of mechanism could be used to prove anything. I could use a similar line of "reasoning" to prove that the world was created and controlled by alien reptiles. Evolution, on the other hand, makes specific predictions which are constantly being supported by evidence from multiple independent areas of human knowledge and discovery. I'm sure the creationists will come up with a list of feeble excuses, conspiracy theories, and out of context quotes in an attempt to disprove the contents of this book but they really have no more credibility than the Flat Earthers! Conclusion In conclusion: Evolution is a fact. Its time to get over it!
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GREATEST SHOW