The Ancestor's Tale

Synopsis

Richard Dawkins starts the tale by talking about history. He claims that evolution rhymes and patterns recur. He talks about our universe that has its own remarkable set of laws and constants which are capable of generating us and other organisms living on this planet. Not only it is capable of generating organisms, it is capable of evolving them too. He claims that biological evolution has no privilege line of descent and no designated end. Evolution has arrived at many millions of interim ends and organisms are still evolving. He believes that evolution is directional, progressive and even predictable. He also talks about how homo sapiens tend to think that they are more evolved than other, but that's not true, all the other species have gone through evolution too. They just have inherited different traits that helped them survive through natural selection. Dawkins claims that all species are equal. He uses backward chronology, instead of forward chronology because in backward chronology, no matter where you start, you end up celebrating the unity of life. While going forward just extols diversity. In a backward chronology, the ancestors of any set of species must eventually meet at a particular geological moment. The last common ancestor is the one that they all share which he calls "Concestor". The oldest concestor is the grand ancestor of all surviving life forms on this planet. There is a single concestor of all surviving life forms and its evidence is that all that have ever been examined share the same genetic code and the genetic code is too complex to have been invented twice. There is no sign of other independent origins of life and if new ones arise, they would probably be eaten by bacteria. This book is a pilgrimage to discover human ancestors and as it progresses, it meets other pilgrims (organisms) who join humans in order as the book reaches the common ancestor that human share with them. Human only passes 40 rendezvous before hitting the origin of life itself. In each rendezvous, we find one particular ancestor, the concestor which has the same labeling number as the rendezvous. All the creatures in this tale are alive except for 2 classes. The two exceptions are Dodo and Handyman. Dawkin’s book’s structure is inspired by Geoffrey Chaucer's The Canterbury Tales. At each rendezvous point, Dawkins recounts interesting tales concerning the cousin animals which are about to join the band of pilgrims. Every newly recruited species, genus or family has its own peculiar features, often ones that are relevant to human anatomy or otherwise interesting for humans. For instance, Dawkins discusses why the axolotl never needs to grow up, how new species come about, how hard it is to classify animals, and why our fish-like ancestors moved to the land. These peculiar features are studied and analysed using a newly introduced tool or method from evolutionary biology, carefully woven into a tale to illustrate how the Darwinian theory of evolution explains all diversity in nature.

Even though the book is best read sequentially, every chapter can also be read independently as a self-contained tale with an emphasis on a particular aspect of modern biology. As a whole, the book elaborates on all major topics in evolution.

Dawkins also tells personal stories about his childhood and time at university. He talks with fondness about a tiny bushbaby he kept as a child in Malawi (Nyasaland). He described his surprise when he learned that the closest living relatives to the hippos are the whales.

The book was produced in two hardback versions: a British one with extensive colour illustrations (by Weidenfeld & Nicolson), and an American one with a reduced number of black-and-white illustrations (by Houghton Mifflin). Paperback versions and an abridged audio version (narrated by Dawkins and his wife Lalla Ward) have also been published.

The book is dedicated to Dawkins' friend and mentor, population geneticist John Maynard Smith, who died shortly before the book went to press.

List of rendezvous points

Dawkins uses the term concestor—coined by Nicky Warren—for the most recent common ancestor at each rendezvous point. At each rendezvous point, we meet the concestor of ourselves and the listed species or collection of species. This does not mean that the concestor was much like those creatures; after the "rendezvous", our fellow "pilgrims" have had as much time to evolve and change as we have. Only creatures alive at the time of the book's writing join us at each rendezvous point. Except for a few special cases, numerous extinct species and families such as the non-avian dinosaurs are excluded from the pilgrimage.

Non-chordate animals

Note: From the lancelets onward, Dawkins only provides dates under duress stating that, "dating becomes so difficult and controversial that my courage fails me".

Non-animal eukaryotes

In what Dawkins calls the "Great Historic Rendezvous", he describes the significantly important event of endosymbiosis, which results in the beginnings of eukaryotic cells. In his estimates, this occurred in two or three steps, roughly two billion years ago. Firstly, bacteria, perhaps related to Rickettsia, entered proto-protozoan cells. For one reason or another, the bacteria were not digested and did not kill the cell. The cell offered protection to the bacteria, and the bacteria provided energy to the cell, resulting in a mutualistic symbiotic relationship. This is the speculated origin of mitochondria. Subsequently, photosynthetic bacteria (thought to be related to cyanobacteria) entered some, but not all, of these mitochondria-containing cells. These ancient bacteria evolved to become chloroplasts, and the cells became the Plant and Algal lineages. Meanwhile, the cells which this second endosymbiotic relationship did not occur in went on to form the Kingdoms Fungi and Animalia, as well as various Protozoa.

Chloroplasts and mitochondria have their own genomes, and they replicate independent of the cell in which they live. Dawkins acknowledges how the endosymbiotic theory proposed by Lynn Margulis is now virtually universally accepted.

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