Human only passes 40 rendezvous before hitting the origin of life itself. 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. There is no sign of other independent origins of life and if new ones arise, they would probably be eaten by bacteria. 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. The oldest concestor is the grand ancestor of all surviving life forms on this planet. The last common ancestor is the one that they all share which he calls 'Concestor'. In a backward chronology, the ancestors of any set of species must eventually meet at a particular geological moment. While going forward just extols diversity. 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. Dawkins claims that all species are equal. They just have inherited different traits that helped them survive through natural selection. 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. He believes that evolution is directional, progressive and even predictable. Evolution has arrived at many millions of interim ends and organisms are still evolving. He claims that biological evolution has no privilege line of descent and no designated end. Not only it is capable of generating organisms, it is capable of evolving them too. 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. He claims that evolution rhymes and patterns recur. Richard Dawkins starts the tale by talking about history.

The Ancestor's Tale by Richard Dawkins