Thursday, January 11, 2007

Evolution is NOT blind chance

At one point in Woody Allen´s excellent movie Match Point, the main characters, all coming from the British upper class, are having a conversation about the meaning of life. Chris Wilton (see picture) played by Jonathan Rhys Meyers, comments that scientists are becoming more and more certain that there is no meaning to life, that we are all here by blind chance (after which the other in the company desperately tries to change the subject. I do not know whether this is what Woody Allen believes, a fast google search suggested that he was an atheist so maybe he is just having Chris say this because it is something people often think. In any case, this is something you hear again and again, and it is quite tedious to be frank. It is also a cause of concern if you ask me. If people hear that evolution is the same as blind chance when they go to the cinema, have a chat at the pub or turn on the telly, then they might start to believe that it is in fact so, even though it is not.

(Warning, spoilers in this paragraph!!!)
I do not know if it is a coincidence that it is the same Chris Wilton who later in the movie commits adultery, makes his lover (played by Scarlet Johansson) pregnant because of carelessness, and then kills her, her neighbour (to make it look like a drug related crime), as well as his own child that is growing inside his lover. I am personally inclined to believe that Woody Allen is well aware of this "coincidence" considering the many references made to Dostoevsky. Dostoevsky thought that without a religion and a God who punish bad behavior and rewards virtuous behavior, we would all be savages.

I had a similar experience one late evening about two years ago when I was visiting my father on Jamaica. I was zapping around on the telly to see if I could find anything interesting to watch. I finally stumbled upon a program in which a scientist would, in a very intriguing way, describe the amazing feats performed by many animals. Most vividly I remember his description of a lizard. He showed how, on a microscopic level, this lizard had almost perfect machinery for walking in the roof. In the end he asked, "do you really believe that this lizard came about through pure chance?". He went on to say, "of course not, it is obvious that it has been designed to do what is does". Since I liked his descriptions of the animals I was actually quite saddened when I learned that he had bought into the idea that evolution is the same as blind chance.

Considering that it such a widespread and often articulated myth, it is perhaps not so strange that people believe that evolution and blind chance are synonymous. To me the fact that evolution is not the same as blind chance, complete randomness, accident etc is extremely obvious. Random mutations change the phenotype of the individual with the mutation. This change in the phenotype can increase the chance of the individual surviving, it may decrease the chance of the individual surviving, or it may have no effect on survival. When the mutation affects the chance of survival (or more accurately, the chance of copying genes into the next generation), natural selection will either favour that mutation, or work against it.

To illustrate, imagine a hypothetical population of rabbits. On average they get the same number of offspring, and they are equally likely to be eaten by whatever animals eat rabbits (is it foxes??). However, one day, two happy rabbit parents give birth to a rabbit baby with a mutation in a gene that affects the sensitivity of the retina. This new baby rabbit, as a result of its improved retina is ten percent more likely to discover a predator in time and therefore avoid being consumed. When this baby rabbit (unless he or she is eaten) becomes a proud parent one day, the offspring inherits the improved retina and therefore the higher chance of survival in encounters with predators. How long would it take for a mutation that increased the survival chance by 10% to spread throughout the whole population? Is it one thousand generations, or a million perhaps? No, if you do the math in this hypothetical example a more plausible estimation would be around 15 generation. At that point, due to the better survival chance of individuals with the mutation, all rabbits will have the new retina. That is how natural selection works. EVOLUTION IS NOT THE SAME AS BLIND CHANCE!

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