Wednesday, December 22, 2010

The Greatest Show on Earth

These last few days I finished reading the second half of Richard Dawkins' The Greatest Show On Earth and was rewarded with the best collection of evidence for evolution I have ever seen amassed in a single place.  Even for someone such as myself, fully convinced of its factual reality, I am even more in awe of its effects all around us.  When I was in high school, I recall creationism being mentioned as an alternative idea to evolution.  But whereas the evidence for evolution was tangible and all around us, it was evident to me (and probably many of my other classmates) that creationism had no such evidence.  Nonetheless, the two theories didn't seem inherently incompatible on that basis alone.  Like many people today, and the early Darwin, I adopted a combination of the two.  When I went to college, the supporters of creationism needed no help from anyone else in discrediting their position.  The untenability of creationism became all the more plain when I came to the conclusion that religion itself was not only insupportable but positively undesirable.  As a younger man, and like most religious folk today, I was guilty of the logical falacy of argumentum ad consequentiam (402).  After reading Dawkins book, I have a greater sympathy for the frustration he feels when he encounters evolution deniers. 

Dawkins described many important evolutionary scientists and their work, among those I found most interesting were Richard Lenski's experiments with E. coli (117), John Endler's work with guppies (133), and Sydney Brenner's work with C. elegans (243).  In addition, the description of recent fossil discoveries, such as Puijila darwini were very interesting, and animals visibly evolving within our lifetime, like P. sicula (113). 

I also learned something about human diversity.  It is estimated that Homo sapiens walked out of Africa 100,000 years ago (186) and diversified into all the races that we see around the world today.  I have sometimes wondered if, in our modern world we would begin to lose genetic diversity as there are no longer physical barriers to prevent races from interbreeding.  However, Dawkins uses the metaphor of shuffling and reshuffling cards in a pack to demonstrate the combination of parental genes in offspring, and that therefore “there is no such intrinsic tendency for variation to decrease in a population” (29) when different gene sources combine.  “Genes don't blend, they shuffle.”  Subtle point, but important and easily overlooked.  So even if all the people in the world are equally as likely to interbreed with any other person, no genetic diversity will be lost as a result of it [see also this]. 

After reading this book, I realized more than before that “All animals are much closer cousins to each other than we used to think.” (359)  Even insects, surprisingly, bear marked similarities to you and I.  If you don't believe that, then read the book.


  1. Creationism was mentioned by the instructor?

  2. Creationism or Intelligent Design, and it wasn't dwelt on for long admittedly. But for that matter, neither was evolution as I recall. You know, the "progressive Christian" climate allowed enough room for both, and no one complained or cared much. PZ might say "absence of evidence is evidence of absence", but not we, at least not then.

  3. That is quite astonishing. I never heard one peep about creationism in my high school. I didn't take the higher level biology classes, but I was good friends with the biology professor and I don't think he would be the type to mix religion and science. All my high school teachers seemed to have understood that a student could get all the religious schooling that that student's parent(s) wanted from a church.

    But what you have said is really even more astonishing to me because the biology room at your school was so well stocked! Talk about an abundance of evidence for one side, evolution, and absolutely none for the other, creationism.

    That it was even discussed seriously by the instructor brings back memories of when they crossed out the word "demon" and replaced it with "sweetie" in music class because some parents were outraged that the word "demon" was being sung by their children. That unilateral accommodation aggravated me even at that young age because "sweetie" did not fit at all in the song--it neither rhymed nor crafted the right mental imagery. I personally refused to make the switch and always sang "demon" thereafter.

  4. Oh, and when you say, "the supporters of creationism needed no help from anyone else in discrediting their position", I can only think back on when we were at that outing and one of the young-Earth creationists insisted that rainbows were created by God and had not existed until after the Flood. I still get a good chuckle whenever I think about that to this day.

  5. I wouldn't say that it was discussed seriously by the instructor at all. Creationism is a very weak argument to begin with, and it is only remotely attractive where the question of the origin of life is concerned. That was the context in which it was raised. "How did life begin?" Evolutionary biology might say that under the right conditions it can arise from non-living materials, whereas Intelligent design advocates say that life cannot spontaneously form on its own - it must be created. That was about the sum total instruction on the subject of creationism that I received in high school. Thereafter the discussion turned to what conditions we might expect to have supported or given rise to early life on Earth and how scientists have tried to replicate these conditions in the lab.

    Between pages 416 to 422, near the very end of Dawkins' book, he begins to talk about this subject: "We know a great deal about how evolution has worked ever since it got started, much more than Darwin knew. But we know little more than Darwin did about how it got started in the first place... we have no evidence bearing upon the momentous event that was the start of evolution on this planet." Nevertheless he remains hopeful that in the next few decades we will be able to reconstruct the events leading to life. Dawkins is an advocate of the RNA World hypothesis.