The Ancestor's Tale

Evolutionary biologist Richard Dawkins structures this sweeping account of life's history as a backward pilgrimage through time, modeled on Chaucer's Canterbury Tales. Beginning with modern humans and traveling approximately four billion years into the past, the journey traces human ancestry to the origin of life. Pilgrims from other species join the march at roughly 40 "rendezvous" points, each marking a shared ancestor, or "concestor," and each telling a tale that illuminates some principle of evolution.

Dawkins opens by warning against two temptations: imposing false patterns on history, and treating the past as aimed at producing humans. A backward chronology avoids this "conceit of hindsight," since tracing ancestry in reverse from any modern species converges on the same universal ancestor. He outlines three methods for reconstructing evolutionary history: fossils, DNA (a "renewed relic" copied with extraordinary fidelity across billions of generations), and triangulation, which compares living organisms to infer the characteristics of shared ancestors.

The pilgrimage begins with recent human history. The Farmer's Tale recounts the Agricultural Revolution of roughly 10,000 years ago, describing how domestication altered animals and humans genetically, as illustrated by the evolution of lactose tolerance in pastoral peoples. The Cro-Magnon's Tale addresses the "Great Leap Forward" of approximately 40,000 years ago, when early modern humans known as Cro-Magnons began producing cave art and other cultural artifacts despite no detectable change in anatomy.

At Rendezvous 0, the most recent common ancestor of all living humans, Dawkins uses mathematical modeling to argue that this individual probably lived only tens of thousands of years ago. Eve's Tale distinguishes "gene trees" from "people trees," explaining that each gene traces its own path through history, and presents geneticist Alan Templeton's "Out of Africa Again and Again" theory, which reconstructs at least three separate migrations out of Africa rather than a single exodus.

Before Rendezvous 1, the pilgrimage pauses at "shadow pilgrim" milestones representing extinct species granted honorary pilgrim status. Dawkins describes the Neanderthals, whose extracted DNA suggests rare or no interbreeding with modern humans, and examines Homo ergaster, the first species clearly different from modern humans. The Handyman's Tale establishes that the human brain is roughly six times larger than expected for a mammal of our weight. Among the australopithecines, extinct early human relatives predating the genus Homo, Little Foot's Tale reviews theories for why bipedalism evolved, including zoologist Jonathan Kingdon's proposal that ground-level foraging adaptations incidentally made the body more comfortable upright.

At Rendezvous 1, approximately five to seven million years ago, chimpanzees arrive. The Bonobo's Tale establishes a key principle: Humans are exactly equally related to both common chimpanzees and bonobos, because closeness is determined by shared ancestry, not resemblance. Subsequent rendezvous add gorillas, orangutans, and gibbons. The Orang Utan's Tale argues on grounds of parsimony (preferring the explanation requiring the fewest changes) that the ancestor of all modern apes migrated from Africa to Asia before some descendants returned. The Gibbon's Tale explains methods for constructing evolutionary trees, including parsimony and likelihood analysis (selecting the tree most probable given the data), and draws a parallel to the Canterbury Tales Project's analysis of variant Chaucer manuscripts.

Old World monkeys, New World monkeys, tarsiers, and lemurs join in succession. The Howler Monkey's Tale traces how color vision genes arose through duplication, showing that trichromatic vision evolved independently in Old World primates and howler monkeys. The Aye-Aye's Tale uses Madagascar as a showcase of island biogeography, the study of how isolation shapes evolution on islands.

Crossing the Cretaceous-Tertiary boundary approximately 65.5 million years ago, Dawkins discusses the meteorite impact that ended the dinosaurs. He argues that molecular evidence favors a "Delayed Explosion" model in which mammalian lineage splits predated the extinction but visible diversification followed. Successive rendezvous add rodents, laurasiatheres (carnivores, ungulates, bats), marsupials, and monotremes. The Hippo's Tale reveals that hippos are closer relatives of whales than of pigs. The Beaver's Tale introduces the "extended phenotype," arguing that structures like a beaver's dam are legitimate products of its genes. The Marsupial Mole's Tale surveys convergent evolution between Australian marsupials and placental mammals, and the Duckbill's Tale demonstrates the platypus bill as a sophisticated electrosensory organ.

Bridging the gap to Rendezvous 16, Dawkins traces three successive waves of mammal-like reptiles that dominated the land before the dinosaurs. At Rendezvous 16, approximately 310 million years ago, reptiles and birds arrive. The Galapagos Finch's Tale describes biologists Peter and Rosemary Grant's documentation of natural selection among Darwin's finches. The Peacock's Tale applies sexual selection theory to three human evolutionary puzzles: loss of body hair, bipedalism, and brain enlargement. The Elephant Bird's Tale explores ratites (large flightless birds such as ostriches and emus) across the fragments of the ancient supercontinent Gondwana.

Rendezvous 17 adds amphibians. The Salamander's Tale uses ring species, in which populations intergrade continuously around a geographical barrier yet fail to interbreed where the ends meet, to argue against insisting on sharp boundaries between species. The pilgrimage then passes through lungfish, ray-finned fish, sharks, and the jawless lampreys and hagfish. The Cichlid's Tale describes explosive speciation in Africa's great lakes.

Beyond the vertebrates, lancelets, sea squirts, and echinoderms join, followed by the massive influx of protostomes at Rendezvous 26, a major animal branch encompassing arthropods, molluscs, and many worm groups. The Fruit Fly's Tale explains Hox genes, linearly arranged control genes governing body patterning shared by organisms as different as flies and mice. The Rotifer's Tale presents bdelloid rotifers, microscopic animals that have apparently thrived without sexual reproduction for 80 million years, as a challenge to evolutionary theory. The Velvet Worm's Tale addresses the Cambrian Explosion, rejecting the idea that new phyla sprang into existence overnight while acknowledging uncertainty about the pace of early animal diversification.

The remaining rendezvous add cnidarians (jellyfish and corals), ctenophores (comb jellies), sponges, choanoflagellates (single-celled relatives of animals), fungi, amoebozoans (amoebas and slime molds), and plants. The Mixotrich's Tale introduces the origin of the eukaryotic cell through the absorption of free-living bacteria that became mitochondria and chloroplasts. At the final rendezvous, archaeans (a distinct prokaryotic domain) and eubacteria (the main bacterial domain) complete the pilgrimage. The Rhizobium's Tale explains why only bacteria have evolved a true freely rotating wheel, and Taq's Tale argues that bacteria span a far greater biochemical range than all other life combined.

At "Canterbury," the origin of life, Dawkins argues that the crucial event was not the origin of metabolism but of heredity: the first self-replicating molecule capable of producing copies resembling the parent more than a random entity. He discusses the RNA World hypothesis, which proposes that early life used RNA as both genetic material and catalyst; biochemist Sol Spiegelman's experiments evolving RNA in test tubes; and astrophysicist Thomas Gold's theory that life may have originated deep underground in hot rocks.

In The Host's Return, Dawkins surveys evolution's forward course. Using convergent evolution across isolated continents as evidence, he argues that evolution is more repeatable than pure contingency would suggest. He defends a concept of evolutionary progress driven by arms races between predators and prey, and introduces the "evolution of evolvability," proposing that major innovations like sexual reproduction, multicellularity, and segmentation permanently improved lineages' capacity to evolve. He closes by expressing amazement that life emerged from cosmic simplicity and eventually produced beings capable of comprehending the process, asserting that the real world's grandeur makes supernatural explanations unnecessary.