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Book review Science

The Ancestor’s Tale Offers a Fascinating Journey Back to our Roots

In this review published at Countercurrents, I examine Dawkins’s encylopaedia of the tree of life.

[Image: the front cover of the 2nd. edn.]

The Ancestor’s Tale (2nd ed.) (2016).  Richard Dawkins and Yan Wong.  Weidenfeld & Nicolson, Great Britain.

The subject of Richard Dawkins’s popular-science books has always been ambitious: life itself.  The Ancestor’s Tale is an even more ambitious entry in his oeuvre.  It dives into the findings, challenges, and methods of evolutionary science using the frame narrative from Chaucer’s Canterbury Tales: a tavern host leads a group of pilgrims to Canterbury, and to while the journey everyone tells tales.  The Ancestor’s Tale takes Homo sapiens on a pilgrimage back to the origin of life, stopping for rendezvous with other pilgrims.  Each rendezvous occurs at the point when the groups meeting shared their last common ancestor (“concestor”).  We start with the concestor of all currently living humans: who, as Dawkins explains via the Chang One theory – the first of numerous clear expositions of other scientists’ work – lived <13,000 years ago.  Hominids meet chimpanzees 5-7million years ago.  From here, via 40 rendezvous to the origin of life itself, at “Canterbury,” is a 4billion year pilgrimage.  It’s a long journey, and despite a few hiccups inevitable in backwards time-travel, Dawkins is a masterful “host.”  As always, he is fascinated by the peculiarities of species, fluent in explaining complex theories, and able to inspire or entertain with tidbits from British literature.  This second edition notes differences in the sequence of rendezvous from the first, and notes points where further research may re-sequence, combine, or re-date rendezvous.  Inevitably, the reader is drawn into the exciting, collaborative, and astonishing work ongoing in biology.

The chapters are titled by ever-larger ‘clades’ or families of organisms – from “Rodents and Rabbitkind” to “Choanoflagellates,” with Dawkins telling the tales of key member-species.  Each rendezvous is dated, and commences by describing the likely appearance and behaviour of the concestor, based on fossil evidence and living descendants.  Dawkins then tells the tale of some key family-member/s.  E.g. our rendezvous with the protostomes is “the biggest of all, a gigantic rally of pilgrims” 560million years ago.  We learn how the protostomes differ from our current band of pilgrims, the deuterostomes.  This genealogical device is useful: going backwards in time, we learn about the progressively larger ‘clades’ to which we belong, and the (often embryological) features through which taxonomists distinguish clades.  The portraits of individual living organisms and dead concestors are complemented by gorgeous photos and full-colour reconstructions.

[Image: Illustrations from the book of of two of our 40 concestors.]

The backwards journey is a clever device to obviate teleological thinking.  Humans, Dawkins stresses, are merely one twig-end in the vast tree of life, no more evolved than any other species: including so-called “living fossils.”  This journey could be begun from any starting-point – starfish or protozoa – and we’d still reach Canterbury.  Inevitably, the backwards journey means that clades don’t always get room proportionate to their significance in the tree of life.  Plants and fungi are, Dawkins notes, extremely genetically diverse; their processes of speciation differ from those of animals; yet our rendezvous with them are relatively brief.

In a sense, this doesn’t matter.  While several rendezvous offer colourful species portraits – see jellyfish and duck-billed platypus – they are really contexts for diving into specific challenges and solutions of evolutionary science.  “The Cichild’s Tale” narrates how one species of cichlid in Lake Victoria evolved, in <10,000 years, into 450.  This microcosm furnishes a case-study for how geographical isolation, key to evolutionary theory since Darwin, drives speciation.  “The Grasshopper’s Tale” describes research on grasshoppers’ remarkable ability to distinguish the calls of opposite-sex members of their own species.  This provides a lesson on how self-segregation by individuals of a species-subgroup can lead to full speciation even without geographical separation.  “The Gibbon’s Tale” revisits The Canterbury Tales for a methodological analogy.  To arbitrate between competing family trees of the numerous extant versions of Chaucer’s epic, literary scholars statistically analyse letter-by-letter differences in the text.  Similarly, Dawkins explains, taxonomists statistically analyse amino-acid differences between various proteins to arbitrate interspecies family trees – in this case for gibbons.

This book is highly intratextual, with numerous cross-chapter references.  E.g. the idea that taxonomies rely on biological molecular clocks is developed across several chapters scattered across the book.  One chapter, surprisingly late in the book, explains radiocarbon dating.  An early chapter explains why radioacarbon dating offers a gross temporal resolution, inadequate to arbitrate competing family trees, whereas biological clocks offer a finer one.  What biological clocks are, why each clock has a different speed, what evidence molecular biologists use to calibrate them, and how multiple clocks can be used to arbitrate family trees – each of these ideas is explained clearly and in due detail, but these ideas are scattered across chapters.  To its credit, the book’s structure allows the chapters to be read in any order.  The reader interested in learning about a particular problem of evolutionary science will leaf back and forth freely, guided by the inter-chapter references.

The book’s excellent supplements complement its intent.  Every chapter shows the pilgrims’ current location on a many-spoked, spiralling tree of life, courtesy OneZoom.  The OneZoom initiative’s online interactive graphic shows the relationships between more than 2million species: an eye-opening visualisation in its own right.  The OneZoom insets in each chapter are a useful companion resource to Ancestor’s Tale.  Complementing the in-depth dives into the work of numerous scientists, the Further Reading section (in addition to a 28-page bibliography) is a handy guide to exploring the empirical research, theories, and statistical/technological innovations of evolutionary science.

[Image: One snippet of the tree of life from OneZoom.org]

I loved The Ancestor’s Tale.  But then, I love all Dawkins’s books.  Would I recommend it?  My answer is a qualified yes.  At 709 pages, and with its tricky structure, this is a demanding read.  From experience with previous Dawkins books, I was hoping to expand my rudimentary biology knowledge – and while I learned many interesting tidbits, the structure of this book obviates its being anything like a systematic biology text.  Clearly, Ancestor’s Tale is meant to be a provocative starting-point to evolutionary science, not a systematic guide.  As such, it’s eminently accessible to lay readers: the language inviting, the portraits of species’ incredible adaptations fascinating, and the expositions of scientific methods clear.  Dawkins fans will love this book as a unique entry in his oeuvre.  So will anyone who takes this book for what it’s meant to be: an introduction to the study of life itself. 

This article was originally published in Countercurrents on Nov 01, 2019:
https://countercurrents.org/2019/11/the-ancestors-tale-offers-a-fascinating-journey-back-to-our-roots

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