Monday, March 28, 2005

The Ancestor's Tale

This book's author is Richard Dawkins .The book is rather long, nearly 700 pages so I'm working my way through it slowly (it was a Christmas present). The subtitle for The Ancestor's Tale is A Pilgrimage to the Dawn of Evolution and it is a collection of "tales" about human evolutionary ancestors.

The book moves backwards through time, starting with the present and moving though a series of common ancestors of humans and other species. These are termed "concestors" by the author. For example, the concestor of chimps and humans lived about 6 million years ago.

The structure of the book is loosely based on Chaucer's Cantenbury Tales (which I never read), where for each concestor (also refered to as a "pilgrim" by the author) there is a tale that illustrates some interesting fact about evolution and the particular concestor. I especially like the various explanations of how evolutionists know certain things. Some of these get quite technical.

I liked the explanation of the method that evolutionary biologists use is to evaluate how the DNA of different organisms relates to each other. This method is similar to how Chaucerian scholars try to figure out which versions of Cantenbury Tales cames first. At the time Cantebury Tales were written, books were copied by hand and the scribes made errors. By studying where these errors occur we can figure out which version of the text came earlier and how the texts relate.

The same holds true for DNA. When organisms reproduce the DNA is copied and sometimes errors (i.e. mutations) occur. By comparing DNA sequence of related organisms, we can get a very good idea of what species descended from what other.

For example, did you know that the nearest relative species to whales is the rhino?

In case you didn't know Richard Dawkins is the author of the famous book The Selfish Gene (I haven't read this one, but Google seems to have the text online). I've read another one of his books: The Blind Watchmaker.

At the moment I'm on page 269 reading about sexual selection, the is about characteristics that evolve because either the male or the female of the species likes something (eg. the peacock's tail).


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