Monday, October 24, 2005

Biologists' Rejoinder to Intelligent Design

The link above is to a feature article in the Boston Globe that summarizes a new rejoinder from biologists to the aggressive challenges of Christian "Intelligent Design" proponents. Molecular and systems biology has not yet explained the origins of life, although scientists believe that such an explanation is within reach someday. Nevertheless the biologists do claim that evolution itself can be better defended and explained with the latest discoveries in how genetics work. Two key notions here: "modular" building blocks that can be traced back billions of years are shared by many species; and second "complexity" is not an excuse for incomprehensible Intelligence, but rather complexity itself has an observable nature that is being studied and which helps to show how evolutionary variations are produced.

That's my point for today. If you want more, below is an excerpt. And if you still want more, see the link above. If you go further than that, get the books mentioned. Beyond that, you're on your way to training as a biologist. Let me know how you're doing with that.

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"Organisms . . . have a far greater capacity to generate rapid and complex variations than even biologists had previously supposed. Moreover, from the genetic level up to our visible features, organisms have a modular structure. In this sense, complex features are less like singularly intricate structures than a collection of building blocks.

"Significantly, Kirschner and Gerhart write, while random genetic mutations in our DNA code cause variations, these mutations do not create random effects (a traditional working assumption of many evolutionists). Instead, all organisms have maintained an essentially intact set of vital mechanisms-metabolism, reproduction of DNA, growth mechanisms, and more-for at least 2 billion years. These elements, along with a long-conserved body plan common to many animals, serve as the platform for subsequent, often more visible variations.

"Consider the elephant's trunk, the elk's antlers, and the narwhal's tusk, which all appear to be distinct, complex innovations. But as Kirschner and Gerhart point out, the same type of cell guided their growth in each animal. Moreover, the modular structure of life means these body parts could develop without affecting the rest of the organism. (A corollary is that it only takes limited genetic changes to bring about large bodily changes.) So the trunk, antlers, and tusk are really just different expressions of the same type of genetic activity-funneled through the process of natural selection, in which variations useful to a particular environment tend to survive over time.

Kirschner and Gerhart also suggest Behe does not consider modularity in his claim that only "staggeringly complex biochemical processes" lie behind the composition of, say, an eye. As they note, the eyes of insects and mammals, each of which appear to be singularly complex, share important biochemical building blocks and connections among their components.

"People should be asking about the nature of complexity, not just how complex it is," amplifies Kirschner, in conversation. "You look at a clock, and you see that every part is purposely made. That's what you would do if you were an Intelligent Designer. But instead, when you look at biology, you find that there are very few types of parts, and they are being co-opted from one place to another. We have a Lego-like capacity to very easily generate new structures."

{article continues . . .}


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