The Ancestor's Tale - Richard Dawkins

(Homo Habilis skull. The oldest known member of the homo genus)

Not only is life on this planet amazing, and deeply satisfying, to all whose senses have not become dulled by familiarity: the very fact that we have evolved the brain power to understand our evolutionary genesis redoubles the amazement and compounds the satisfaction. - Richard Dawkins

Richard Dawkins gets a bad rap. It is generally agreed by those who read him that he is equally gifted as both a scientist and as an author. However this is not how most people know him. Most people know him by his book The God Delusion and his public appearances following that book. He was so much in the public eye that he was satirized in a multi-part South Park episode that lampooned both him and zealous atheists. I think it would be a mistake to dismiss his other works just because you find his God bashing distasteful. There is something to learn from his writing even if you do believe in a god (as long as you're accepting of the theory of evolution).

The Ancestor's Tale is written as a backward pilgrimage to discover the ancestors of human beings and eventually the ancestors of all life. The structure is vaguely based on Chaucer's The Canterbury Tales but I'm not really that familiar with Chaucer so I won't comment on it. The pilgrimage starts with modern day man and then traces our ancestry back until we reach multiple rendezvous points with other species. The evolution of man, or any species, can be seen as starting from the beginning of life, and branching off in a tree-like fashion as organisms speciate. This forms a tree similar to the one shown below for eukaryotes (plants, animals and fungi). For those interested, this tree was formed using DNA comparison analysis, and the length of the branches roughly marks the difference in the DNA. Note how on this scale humans and chimps don't even qualify as having separate branches.

(Eukaryotic evolutionary tree. Taken from Science issue 199, 1978)

Often Dawkins tries to imagine what our common ancestor (or as he terms it concestor) with another branch looked like. One the chart above this would be the intersection or 'branching point' between two lines. I found this exercise to be utterly fascinating, if occasionally disappointing. Often when trying to imagine what our concestor looked like, Dawkins postulates that it looks exactly like the creature we were joining! When humans (and all those who branched off with us) join the lemurs, he images that our concestor would be lemur! When we join fish, you can guess again what he imagined that concestor to look like.

The most fascinating thing about this book to me, was the order in which we 'joined' other species. Are we closer to reptiles, birds or amphibians? Did we evolve from single celled organisms like you might see today or are they a sister group to us? Did we come from bacteria or again are they sister to us? (Quick note on this one, no one knows!) As new branches and groups of species join us on our journey Dawkins often uses a 'tale' about one of the joining species to elucidate something about the way evolution works, or just to point out something cool. These 'tales' help keep the book from being too technical and really keep it moving.

Dawkins also uses his time to help explain how we determine these rendezvous dates and figure out which other species share a more recent concestor with us. He discusses fossils and radioactive dating in rocks to be sure, but the most interesting technique he goes over is the widely used DNA comparison analysis. People who question how we know any of this stuff, and wonder how fossils can tell us so much about our past, should really try to understand how important DNA analysis between contemporary species is in helping us pinpoint our evolutionary roots. His introduction to this is technical enough to satisfy my scientific interests, but I'm sure it's a greatly dumbed down description. I imagine that this book could be possibly dull for an experienced zoologist or geneticist, but it was perfect for someone with general (but not specific) scientific knowledge.

Although the order of concestors closest (most recent) to us is pretty well known once we start going back into the Pre-Cambrian things start getting trickier. Dawkins makes his best guess, but makes sure to reiterate time and time again that he is making an educated guess. To me this is the difference between the scientific and religious way of thinking, and what makes something like the theory of evolution vastly superior to the theory of creation. Evolutionists will freely admit when they don't know the answer to a particular problem, where as creationists will just once again fall back on their old arguments. I don't want to turn this into another evolution/creation debate but reading books like this that help elucidate the wonders of evolution and nature make it hard not to get frustrated with the creationist point of view. Dawkins offers his (non-inflammatory) feelings in the quote below.

My objection to supernatural beliefs is precisely that they miserably fail to do justice to the sublime grandeur of the real world. They represent a narrowing-down from reality, an impoverishment of what the real world has to offer.