The Ancestor’s Tale
 

Somewhat as Geoffrey Chaucer did in The Canterbury Tales, Dr. Richard Dawkins narrates this backward chronicled story of forty “rendezvous points” in evolutionary history, when various groups join the human ancestral lineage on a pilgrimage. The procession is “headed” to Dawkins’ version of Canterbury somewhere on or in earth-space some four billion years ago, where life began. Imagine if you will, a destination that might euphemistically be called “the mother of all ...“ As each of the forty groups joins the pilgrimage, the tale of the common ancestor (concestor) of the new group is told — in terms of that concestor’s contribution to evolutionary history.
 

Gravity, Relativity, atomic structure and electricity are theories, as is biologic evolution. Scientists no longer argue whether evolution explains our world. They agree that it does so in hundreds of ways with an overwhelming web of correspondence with every facet of reality. What the argument is about is how to word the footnotes to the documentation already written. Many of the remaining disagreements have to do with precisely how to chronologically order the receipt of human heritages (genes) from DNA/RNA copies that existed 500 million to 1000 and more million years ago. Dr. Dawkins explains the various methods of dating and cross referencing used to establish the “time” of each of his rendezvous points and his guestimate of the number of generations that have transpired since it occurred.
 

He presents the most lucid explanation I have seen of the use of radioactive isotopes for establishing dates of artifacts and fossils. Other reference points used to time stamp antiquities are ring patterns of tree growth, magnetic patterns frozen in igneous rock and other natural patterns. A highly accurate picture of the chronology has now been formed and is being updated on a continuous basis. As far as genetic heritage is concerned, every day brings new discoveries about old mysteries of which species is truly ancestral to others, filling in blanks, re-ordering chronologies, etc. Tools are daily being sharpened to improve and extend DNA validations and verifications of kinship.      
 

Dr. Dawkins’ several discussions on speciation are enlightening. The primary distinction between species has been that different species don’t interbreed. He highlights several instances where individuals that are similar to each other do not interbreed, not due to incapacity, but due to preference, which after a number of generations leads to speciation. Then there is his description of populations of animals whose habitat is in the shape of a geographical ring. It is assumed that the animals gradually populated the habitat starting at one point and moving in one direction only, eventually populated all the way around the ring. Adjacent samplings of individuals as one travels around the ring are slightly dissimilar, but not enough to be a barrier to interbreeding. This is true except at the “begin/end point” of the circle. At that point, the individuals in habitat at adjacent ends of the broken ring are so dissimilar to each other that they won’t or can’t interbreed, though both can and do with their neighbors in the opposite direction. 
 

I was impressed not only with the treasure trove of mesmerizing biologic information recounted in these tales, but with Dr. Dawkins’ style as an educator. Some of this subject matter is quite complex, yet he has a knack of hinting at the information that is about to flow, giving just the nuts and bolts of it in a straightforward manner, then going back and ferreting out adjustments and exceptions to what has been related. He does this in such a way that one gets it. The reader may not grasp all the nuances or retain all the details as well as an evolutionary biologist would, but he gets it!   
 

Some of the reason for this may be Dr. Dawkins’ penchant for writing prose that is often almost poetic in its elegant nature. Just one example:
 

…“This idea of community, as made up of lower-level units that flourish in the presence of each other, pervades life. Even within the single cell, the principle applies. Most animal cells house communities of bacteria so comprehensively integrated into the smooth working of the cell that their bacterial origins have only recently become understood. Mitochondria, once free-living bacteria, are as essential to the workings of our cells as our cells are to them. Their genes have flourished in the presence of ours, as ours have flourished in the presence of theirs. Plant cells by themselves are incapable of photosynthesis. That chemical wizardry is performed by guest workers, originally bacteria and re-labeled chloroplasts. Plant eaters, such as ruminants and termites, are themselves largely incapable of digesting cellulose. But they are good at finding and chewing plants. The gap in the market offered by their plant-filled guts is exploited by symbiotic micro-organisms that possess the biochemical expertise necessary to digest plant material efficiently. Creatures with complementary skills flourish in each other’s presence.” 
 

This book is the epitome of intelligent design. It is intelligently designed to lay waste any claim that Intelligent Design (or any other supernatural handmaiden) had anything to do with the development of life on earth — or anywhere else, for that matter. Dr. Dawkins says that …his “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.” And in this book’s thorough deconstruction of the process of human biological development through its exposition of heritages acquired from the forty “concestors,” he has done elegant justice. He has shown us the “sublime grandeur of the real world” as well as one could expect four billion years of evolution to be explained. This is one heck of a book! I highly recommend it, but don’t expect to read it in an afternoon. Better figure on joining this caravan a number of times over a period of a few weeks.  
 

© 2004 R. Leland Waldrip