Richard Dawkins, The Greatest Show on Earth: The Evidence for Evolution. Free Press, Sept. 2009.
This is the second book to appear in 2009 that set out to present the basic evidence for biological evolution. I covered the other one, Jerry Coyne’s Why Evolution is True, yesterday, and it occurred to me to wonder which book came first and if one of the author’s might have influenced the other.
Coyne’s was published in February, Dawkins’ in September. Coyne’s book has a blurb by Dawkins on the back cover, along with blurbs from EO Wilson, Christopher Hitchens, and Steven Pinker. Dawkins has a blurb from Coyne, along with blurbs from Matt Ridley, Neil Shubin, and others.
So they had each read each other’s book by the time each was published. But my understanding of the publishing world is that it typically takes a full year from the time a manuscript is delivered to the publisher before the book actually appears in stores. In the first few months the publishers will circulate preliminary copies (ARCs, advanced reading copies) to sympathetic readers precisely to get feedback they use as blurbs on the cover. But given the lead time involved, I doubt either author could have read the other’s with time to update their own manuscripts. Not that it really matters; and why would they need to?
This was something like Dawkins’ 10th book (Coyne’s was his first), and it’s longer than Coyne’s, some 440 pages of text, with several inserts of color plates along the way, with 30 pages of notes, bibliography, and index. Oh wait—Dawkins does include Coyne’s book in his bibliography. So apparently he did see the book and took it into account, at least enough to credit it.
As with Coyne I’m going to clean up and trim my notes a bit but not substantially rewrite them (They’re only 1/3 the length of Coyne’s.) Then I’ll come back and summarize key points here.
I’ve added some [[ 2021: bracketed comments ]] in the description below.
Dawkins spells out in great detail the evidence for the fact of evolution. Dawkins in particular offers evidence to challenge the misconception of creationists. He begins by emphasizing what the words “theory” and “fact” mean in scientific contexts. Then discusses evolution: why the idea took so long to occur, though the idea of “artificial selection” e.g. breeding dogs was well-known; how we date the past; how evolution can occur quickly (e.g. elephants’ tusks); how the idea of “missing links” is a misconception; how a human can arise from a single cell not in a billion years but in nine months; how geographical barriers create new species and explain the distribution of different species around the globe; how our bodies show evidence of vestigal and “unintelligently” designed features; how the ecosystem is terribly designed considered as a whole, and how would creationists explain that?; and finally how Darwin’s worldview, our four kinds of memory, the 2nd law of thermodynamics, and our very existence are consistent with the apparent rarity of life in the cosmos. With an appendix examining acceptance of evolution in various countries — highest in northern Europe, dismal in the US.
Another excellent book, with examination of theoretical ideas and lots of examples of how evolution has and is occurring. Much of it familiar to me already in 2009, but several new points stood out: the idea that a continuum of fossils means that, at some point, the division into species is arbitrary; how DNA is not a blueprint but a set of instructions, refined over millions of years, obeyed locally by individual cells, rather like origami; and how the ecosystem, with its pain and record of history species, is a powerful argument against “intelligent design.”
- This book lays out the evidence for evolution, as none of author’s previous books has quite done. One possible title was ‘Only a Theory’.
Ch 1, Only a Theory?
- Imagine trying to teach Latin and being besieged by deniers who claim Rome never existed. [[ 2021: There is, in fact, such a conspiracy theory. ]] People do claim the Holocaust never existed. Senior clergy have no problem with evolution, though they continue to recite stories of Adam and Eve and some parishioners take them literally.
- Time to revisit what ‘theory’ means – both an explanation of a large amount of data; and an informal hypothesis. Author proposes using ‘theorum’ [sic] for the first meaning; hypothesis works for the second. Strict mathematical theorems are provable in a way scientific ones never are.
- Similarly the word ‘fact’ – though observation is less reliable than supposed. Example: a short film in which observers are told to count basketball tosses, and doing so miss seeing a man in a gorilla outfit walk through the court. [[ The famous “invisible gorilla” also mentioned in http://www.markrkelly.com/Blog/2021/12/08/novella-et-al-the-skeptics-guide-to-the-universe/ Novella ]] Inference can actually be more reliable than observation, in establishing ‘fact’.
- This book will examine the evidence—much as detectives deduce facts from the scene of a crime. [[ I think detective work is an excellent metaphor for science; provisional conclusions change as new evidence comes to light, and no one accuses detectives of being unreliable and “changing their minds” capriciously ]]
Ch 2, Dogs, Cows and Cabbages
- What took the idea of evolution so long to occur? Perhaps the ‘dead hand’ of Plato—essentialism, the idea of ‘ideal’ forms. E.g., that there is an ideal rabbit, and all actual rabbits are variations thereof. Actual rabbits vary; populations overlap. Children are natural essentialists – they need to be, to sort out the world and assign things names. [[ 2009 comment: I like the idea that human nature, in some fundamental sense, perhaps necessarily blinds intelligent creatures to the ‘true’ nature of reality – instead, reality is perceived in a way that favors that intelligence. Analogous to the idea that true believers may really be happier and more productive than people who are content with uncertainty. 2021 comment: lots of evidence since confirms this; except that “intelligence” only exists in the first place to the extent needed to navigate the natural environment. ]]
- In the evolutionary view, there’s a continuum between any two creatures – a series of intermediate creatures, with every adjacent pair capable of reproducing. Imagine a series of rabbit generations—farther back, the less they look like contemporary rabbits. Eventually we reach a creature that was the most recent common ancestor of both the rabbit and the leopard…and then we can retrace the other path, down to the present leopard. The point of connection is the ‘hairpin’… call it the hairpin bend. In principle there’s one between any two animals. It doesn’t mean one ‘evolved’ into the other. Modern species don’t evolve from other modern species… Darwin didn’t know the idea of ‘essentialism,’ but argued against the ‘immutability’ of species using evidence from domestication.
- Darwin wrote a whole book about domestication – especially, e.g., of cabbages, changed over a few centuries into the variety of vegetables we know today. And wolves into breeds of dogs. It is gene pools that are modified this way—a concept Darwin never knew. Genes don’t blend; they shuffle. Darwin came close to realizing the idea. Gene pools are continuously reshuffled; each animal is a sample of the pool. When there is a shift in frequency of genes in a gene pool—that is evolution.
- Humans enforce strict separation between the gene pools of different breeds of dogs—an artificial separation. Human breeders carve gene pools. Sometimes they deliberately blend breeds, e.g. the Labradoodle, but breeding those results in higher than desired variation in the pool, typical of how breeds get their start.
- Mutations are the random changes in genes that are the raw material for evolution… e.g. a single mutation for short limbs, or dwarfism. As animals grow, they usually grow at different rates for different body parts—e.g. bones of the snout growing more slowly.
- The point is that such variation, between breeds of dogs, involves remarkably few genes and can occur in just a few hundred years.
- Such ‘sculpting’ is analogous to human body builders, or specially bred beef cows.
- In fact, eugenic breeding of humans—for athletic prowess, or artistic talent—almost certainly *is* possible, despite opposition on moral grounds.
- Author developed a computer game to simulate generations of biomorphs…illustrating the rapid effects of artificial selection, as in breeding. Next, we see how *random* natural selection has great effects over time.
Ch 3, The Primrose Path to Macro-Evolution
- Continuing the ‘softening-up’ program of introducing ideas that explain evolution—how other animals bring about similar results as human breeding of dogs.
- Consider wild roses, as compared to the many varieties of selectively bred and named roses. Flowers were selectively bred by insects (and hummingbirds, etc). (Background on why plants need to pollinate.) Plants use nectar as ‘payment’ to insects and birds for inadvertently transporting pollen. Darwin predicted the existence of a particular moth with a long proboscis, based on a particular orchid in Madagascar. Some insects prefer certain colors, etc; the feedback enhances the colors, and scents. And insects are ‘bred’ for ability to pollinate.
- Other examples include the males of certain pheasants—‘sexual selection’ in Darwin’s language; or what could be called selective breeding of males by females, who are more inclined to notice colorful males. Other factors than sight can be used: finches bred for their songs.
- Another example: crabs that look like warrior faces are selectively less often eaten by Japanese, and so survive—maybe; or maybe just coincidence, especially considering how easily humans perceive faces in random patterns anyway. Similarly, caterpillars that look like snakes, scare off birds. Deep-sea angler fish lure little fish; the little fish, in a sense, breed more appealing lures—this is natural selection.
- Everyone had known about artificial selection – Darwin realized you didn’t need a choose agent.
- Thus, individuals with superior equipment to survive, are most likely to reproduce and pass on genes for such equipment.
- But there has always been confusion that ‘selection’ somehow implies a selecting agent. Use of the phrase ‘survival of the fittest’ was an alternative.
- The proof is in doing experiments—as breeding, artificial selection, is a experimental form of ‘natural’ selection. Three detailed examples follow…
- Rats’ teeth. Rats can be bred to resistance to tooth decay. Why wouldn’t this already have occurred? Nature is a series of tradeoffs and compromises. Calcium for better teeth might come at the cost of weak bones. Domestication shields animals from various natural risks.
- One theory is that wolves self-domesticated before being taken in fully by humans; they became village dogs, etc. Wolves have a certain ‘flight distance’; this might have decreased as new food sources, rubbish heaps near human villages, became available. In modern times the Russian silver fox was domesticated from the red fox, bred for tameness; only six generations produced tameness, and even other doglike features. (Some genes have multiple effects; pleiotropy)
- Flowers again. Orchids—some of them manipulate insects not via pollen, but by mimicking insect forms, luring male insects to copulate with them. Other examples of coevolution. Or arms races (more in Ch 12)
- Clearly, selection can create big differences in brief amounts of time. How much time is available? 46 million centuries, since the origin of the earth… But how do we know how old things are?
Ch 4, Silence and Slow Time
- People who think the world began less than 10,000 years ago are deluded. Deducing the ages of things is like a detective depending on an estimate of time of death. There is a variety of natural clocks, spanning eight orders of magnitude, with overlapping ranges so they can check on another.
- Tree rings can date something to the nearest year. Patterns in the ring indicate varying weather from year to year. Daisy-chaining from one sample to the next builds up a timeline going back thousands of years (in principle, millions). Sediments and coral reefs have similar annual patterns.
- Radioactive clocks; there are various, each with its own period. Isotopes. Each decays at a characteristic rate. The order of various strata around the globe was deduced before their actual ages were. Dating depends on when the clock is ‘zeroed’ – when a living animal dies (its carbon ratio derived from the atmosphere – continually renewed by cosmic rays), or magma solidifies.
Ch 5, Before Our Very Eyes
- Some instances of evolution occur so quickly we can observe them. Tusk sizes in elephants—a result of poaching. [[ 2021: This is happening now! ]] Lizards in Peru. E. coli, thousands of generations – elaborate, clever experiment by Richard Lenski et al. , involving 12 ‘tribes’ in separate generations of flasks. Another experiment involving guppies.
Ch 6, Missing Link? What do you mean, ‘missing’?
- What creationists mean by them: misconceptions. Each newly discovered ‘missing link’ creates two more missing links! The myth of the ‘great chain of being’, of ‘higher’ and ‘lower’ animals. Examples of coelacanths and similar animals in family trees.
Ch 7, Missing Persons? Missing No Longer
- Human evolution, and ‘missing links’ – partly the result of difficulties in classification. Scientists disagree about particular specimens; if a continuum were truly found, there would have to be some arbitrary point between one ‘species’ and the next.
- Transcript of tv debate in which opponent kept insisting on seeing the actual evidence; author kept telling her to go look in museums.
- Like adult vs minor; an arbitrary distinction.
Ch 8, You Did It Yourself in Nine Months
- How could humans arise from a single cell, even in billions of years? Each person does it in nine months. Ideas of embryology. DNA is not a ‘blueprint’ or plan; it’s a series of instructions, rules that are obeyed locally by individual cells, beginning with the first cell. A little like origami. Details of how chains of cells spontaneously fold over and bend. Etc.
Ch 9, The Ark of the Continents
- The idea of islands – land surrounded by sea; mountaintops surrounded by plains; even lakes surrounded by land. New species are commonly born by being separated by some kind of island. Darwin noticed this in the Galapagos.
- The idea of continents moving; the shape of shorelines; proof in the discovery of rift valleys and spreading ocean floors. The distribution of species on various continents is entirely consistent with these geological observations.
Ch 10, The Tree of Cousinship
- Notice how homologous are mammal skeletons – the shapes and sizes vary, but the arrangement and connections are consistent, as if they all evolved from the same progenitor. Similarly in other kinds of animals; marsupials. Computer simulations. Molecular comparisons reveal the relationships at yet another level. Molecular clocks reveal the apparent intervals between various species, considering they separated at various times and continued to evolve molecularly.
Ch 11, History Written All Over Us
- Evidence in our bodies; goosebumps are vestiges of fur; dolphins and whales; wings on flightless birds; cave-dwellers that have lost their eyes. The human eye with its reversed photocells. ‘Unintelligent design’ is visible in the laryngeal nerve, and the vas deferens in males.
Ch 12, Arms Races and ‘Evolutionary Theodicy’
- The ecosystem itself is terribly designed considered as a whole; so much waste, so much pain. Why trees grow taller—trying to gain advantage over each other, even though all would be better off staying short. Similarly cheetahs run fast, so do their prey; there’s a tradeoff .
- The idea of ‘theodicy’ is to try to justify suffering and evil given a beneficent god. Why is pain so painful?
Ch 13, There Is Grandeur in this View of Life
- The famous last paragraph of Darwin, considered in detail.
- Four kinds of memory, p406: DNA, as a repository of survival techniques; the immune system, as a record of individual survival; memory in our brains, the nervous system; and fourth, culture.
- What the 2nd law of thermodynamics mean, and how creationists claiming that evolution contradicts it reveals their ignorance. (It doesn’t, because of the sun.) Author speculates about various ways life might have originated; the rarity that it originates might explain the Fermi paradox. (I.e. if we know life were more common in the galaxy, the origin problem would be more significant.) We see stars in the sky because stars are needed for forge the chemicals with which life; just as we see huge ecosystems around us, since we are alive. “We are surrounded by endless forms, most beautiful and more wonderful, and it is no accident, but the direct consequence of evolution by non-random natural selection – the only game in town, the greatest show on Earth.”
Appendix: the history deniers
- Author surveys the results of surveys, in the US, UK, Europe, about beliefs of the origin and development of human beings; example results: 40% believe life existed in its present form since the beginning of time; 60% think life as evolved (26% via evolution, 20% of those via a supreme being, 10% don’t know); 10% don’t know.
- Surveys asking whether human being evolved from earlier special of animals found the highest acceptance in northern European countries, at 85% [[ coincidentally? These are the countries with the highest quality of life based on analogous surveys ]], the lowest, Turkey, at 27% (The US is at 26% per the previous survey). Results of surveys about whether human lived at the same time as dinosaurs have inverse correlation to the other surveys.
Largely familiar material, but a couple chapters described things I hadn’t considered or appreciated –
The idea that the increasing continuum of fossils means that, at some point, divisions in species is arbitrary.
The insight that DNA is a set of instructions, without any particular intent, but refined over millions of years via accidental changes and the effects of the results of those changes. E.g., DNA might as well be an enormous series of simply instructions: in terms of left right, or one off—and it’s the sequence, as executed within the organism, that creates the physical being, not by way of any ‘design’ or blueprint.
The observation that the ecosystem as a whole is a powerful argument against ‘intelligent design’. Couldn’t a designer have set up something less wasteful and painful?