The Ancestor's Tale

The Ancestor's Tale: A Pilgrimage to the Dawn of Life is a popular science book by Richard Dawkins and Yan Wong in which the history of life is retraced in reverse chronological order. A growing band of species meet their most recent common ancestors (concestors) at 40 rendezvous points. First published in 2004, it was updated in 2016 to reflect recent discoveries. Many reviewers described it as Dawkins's magnum opus. Dawkins dedicated the book to John Maynard Smith.

Background

The book is patterned on Geoffrey Chaucer's The Canterbury Tales, in which pilgrims on the road to Canterbury converge with other travelers and tell tales. Here, species convene with their common ancestors ("concestors"), and "Canterbury" is the origin of life. The authors emphasize that no extant species is ancestral to any other, but that all share a common ancestor. Evidence for this fact is that the code for translating genes into proteins is universal. Genes and proteins serve as molecular clocks that allow us to determine when species split.

The epigraph is from Mark Twain: "History doesn't repeat itself, but it rhymes." The authors contend that this is true of evolution.

The book was revised in 2016: "The Denisovan's Tale" replaces "The Neanderthal's Tale", while "The Elephant Bird's Tale" has been updated. "The Mudskipper's Tale" was present in the first edition but not the second. "The Armadillo's Tale", about biogeography, is now "The Sloth's Tale". The phylogenetic trees in the second edition are based on OneZoom evolutionary mapping software.

Each Tale illustrates an aspect of evolution. Thus, "The Galápagos Finch's Tale" is about natural selection, "The Peacock's Tale" is about sexual selection, "The Salamander's Tale" is about speciation, and "The Barnacle's Tale" is about how appearances can be deceiving.

Contents

Dawkins begins with humans and moves outwards through successively larger groups: primates, placental mammals, marsupials, monotremes, chordates, animals, eukaryotes and prokaryotes until arriving at the origin of life.

"The Farmer's Tale" tells of the Neolithic Revolution, when humans domesticated plants and animals through artificial selection. "Eve's Tale" introduces mitochondrial DNA, used to trace matrilineal ancestry. "The Chimpanzee's Tale" is about comparative genomics, specifically the comparison of human and chimpanzee genomes. "The Gibbon's Tale" is about phylogeny and introduces themes that run throughout the book.

Biogeography is a theme, illustrated by "The Sloth's Tale". Charles Darwin and Alfred Russel Wallace, who independently discovered the engine of evolution, recognized patterns in the geographic distribution of species, such as that islands often have endemic birds but not mammals; plate tectonics offers an explanation. Multiple independent lines of evidence point to the continents having split from the ancient super-continent Gondwana. After South America split from Gondwana, sloths and other Xenarthrans evolved in "splendid isolation", while after Australia split off, it carried marsupials.

Convergent evolution is illustrated by "The Marsupial Mole's Tale". The marsupial mole is not a mole, but resembles one as it has evolved to fill a similar niche.

"The Galápagos Finch's Tale" is about natural selection and how it can produce rapid evolutionary changehow it can lead to rapid evolutionary change. Other Tales are about peculiar features of their subjects. "The Duckbill's Tale" is about its electroreception and "The Axolotl's Tale" is about neoteny.

The Ragworm's Tale" is about the evolution of left-right symmetry. Dawkins discusses the evolution of eyes, which all develop under the control of the same genes, despite their very different structures in groups such as insects and mammals. Eyes have convergently evolved several times, as Dawkins discusses in "The Forty-Fold Path to Enlightenment" in Climbing Mount Improbable.

"The Mixotrich's Tale" is about symbiosis. Mixotricha paradoxa has bacteria, specifically spirochaetes, which serve Mixotricha as galley slaves in place of cilia to propel itself. Mixotricha is a symbiont, helping its host termites digest cellulose. The authors describe the origin of eukaryotic cells and Lynn Margulis's endosymbiotic theory. Mitochondrion and chloroplasts have their own DNA and divide by binary fission, like bacteria. Margulis surmised that this is because they are descended from free-living bacteria.

"The Choanoflagellate's Tale" is about the evolution of multicellularity. Choanoflagellates can form temporary colonies from a free-living unicellular stage. Sponges have choanocytes, cells that resemble single-celled choanoflagellates, suggesting how multicellularity evolved. "The Mixotrich's Tale" is about symbiosis. Mixotricha paradoxa has bacteria, specifically spirochaetes, which serve Mixotricha as galley slaves in place of cilia to propel itself. Mixotricha is a symbiont, helping its hosts digest cellulose. It lives only in the termite Mastotermes darwiniensis.

The "Rhizobium's Tale" is about the evolution of the bacterial flagellum, likely from a Type II secretion system. Despite the diversity of animal body plans, wheels seem only to have evolved once.

"The Great Historic Rendezvous" is the origin of eukaryotic cells. Mitochondrion and chloroplasts have their own DNA and divide by binary fission, like bacteria. Lynn Margulis's endosymbiotic theory surmised that this is because they are descended from free-living bacteria.

Reception

Carl Zimmer of the New York Times wrote that it is one of the best books to understand evolutionary trees.

Rob Colwell of the Wall Street Journal called it "a fittingly superior beast -- lavishly produced and, weighing in at 1.6 kilograms, substantially heavier than the fully-evolved human brain that thought it up."

Clive Cookson of the Financial Times called it "one of the richest accounts of evolution ever written. It is also an object lesson in the way thorough picture research, carefully commissioned illustrations and good design can enhance even the best text." He adds "He is so good at explaining complex scientific issues that readers will learn painlessly about matters well outside the author's field of evolutionary biology, from maths to cosmology. But he interlaces the hard science with 'pleasing speculations', humorous asides, personal anecdotes and even political observations." He concludes "we have no right to expect a second magnum opus on the scale of The Ancestor's Tale."

Marek Kohn wrote "The success of this book comes from having one truly Chaucerian character: the author himself."

Robin McKie in The Guardian thought it awkward to move backward in time starting from humans and thought this required linguistic gymnastics. Matt Ridley, in the same publication, appreciated the approach of a Chaucerian Pilgrim traveling backwards and the perspective of not seeing other animals as failures.

Jody Hey notes that Dawkins "writes engagingly on evolutionary topics. With a highly self-assured style, he effortlessly draws insightful connections among disparate notions, trapping the curiosity of readers before they know what's coming." However, he says "An unfortunate editorial oversight is seen in the text's occasional straying into political commentary. Worse still, Dawkins at one point chastises Richard Lewontin, the great population geneticist, for sometimes interjecting politics into scientific discourse. This little touch of hypocrisy is hard to miss if you read the entire volume. But such lapses amount to a few dozen words in a weighty, truly wonderful book."

Steve Jones calls it "a rigorous and impressively complete account of the Tree of Life… The Ancestor's Tale achieves the almost impossible: it makes biology (not biochemistry, brain science, or bird-watching, but biology as a whole) interesting again. Everyone possessed of a cell nucleus should read it, and ponder their own unimportance. One mystery remains: what did the star-nosed mole say to the duck-billed platypus?"

Translations

See also

• Evolutionary history of life
• Phylogenetic tree
• Timeline of evolution Timeline of human evolution
• Almost Like a Whale, Steve Jones's update of On the Origin of Species
• Genome, Matt Ridley's exploration of the human genome in 23 chapters, each focusing on a specific gene on a different chromosome
• The Beak of the Finch, Jonathan Weiner's account of Peter and Rosemary Grant's study of Darwin's finches

External links

• , by Connie Barlow, with video, slides and scripts.
• , an interactive fractal explorer of the tree of life, used to make the visualizations in The Ancestor's Tale.