Thursday, 9 April 2009

The Inadequacy of Poe's Law

Just to show that even the arguments of a creationist can evolve, Ray Comfort has reprised his atheist nightmare. But the focus is no longer the banana - the product of artificial selection and human design, he's now moved onto animal. In a "debate", Comfort has shifted his argument to the majestic dog. For those not in the know, dogs like bananas are a product of artificial selection. As far as we can tell, dogs were the first animal to be domesticated by man, some 15,000 years ago in Asia. Dogs are wolves, selected for particular traits that suited the purposes of man.

Adding another level of irony, the dog is actually a very good example of where new species come from. Comfort's cartoonish version of the origin of a new species is that it would be impossible for a male and a female to evolve simultaneously. PZ Myers has as good an explanation as anyone in pointing out the obvious absurdity of Comfort's claim. Just look at the dog breeds that are there now. Great Danes and Poodles both reproduce sexually, a Poodle won't give birth to a Great Dane or vice versa. Yet it was only 15000 years ago that these two shared a common ancestor that reproduced sexually as well.

To get the exaggerated difference between the large Great Dane and the cutesy Poodle, it's taken selection. Each step of the way there has been reproduction between a male and a female. It's that variations that occur by nothing more than the virtue of being born are deliberately bred against. By selecting favourable features and choosing mating pairs that will breed such features, over time those variations will accumulate. All the breeds and all the different features and specialisations in each breed are the result of only 15,000 years of breeding. Yet there are dogs specialised for a myriad of different roles. A Chihuahua may make for a good house pet, but it can't run like a Greyhound, nor can it be used for hunting like any variety of scent hound. Nor is it specialised for being a beast of burden, unlike sled dogs, or be useful with livestock like a cattle dog is.

I've got to wonder if Ray can be so unintentionally stupid, it's hard to imagine that someone can be that profoundly ignorant when it comes to science. Evolution doesn't happen in individuals, rather it happens in populations. In the case of mammals, that includes both males and females. There's been direct breeding from the grey wolf to the German Sheppard as there has been to the Great Dane and to the Poodle. Each step of the way there has been variation, and there will be an accumulation of these traits over time. This obviously is a much faster process than what happens with natural selection in the wild, but the principle is the same. Animals reproduce, there are born both male and female - and those offspring will both compete to reproduce. Thus the cycle of life brings on change over time. That is the inevitability of evolution, highlighted by an unintentional 15,000 year global experiment.

2 comments:

Reasonably Aaron said...

Thoroughbred breeding of dogs is a good argument against eugenics. When you consider that many Dalmatians are born blind, thanks to the lack of genetic diversity, dogs give us the insight into what would happen if we were to breed "pure" humans with each other.

I say this because many people use the Hitler argument against evolution, whereas Hitler was only advocating an "animal husbandry" approach to breeding humans, something we have done with animals since day one.

Kel said...

I always find that link between Hitler and evolution quite an odd thing to say, because eugenics is not an extension of evolution - rather it's a practice that has been conducted on animals and plants since the dawn of civilisation. I wonder how many of them even realise that their household pets are all because of this practice?

It's definitely a good argument against eugenics 1.0, but eugenics 2.0 i.e. Gattaca would avoid such trappings. So can that argument hold when there are the potential of designer babies? Could there be an ethical means of tinkering with life if it meant eliminating various hereditary genetic conditions?