Monday, August 22, 2005

Life's Complexity: Darwinists and Doubters Clash

NYTimes: In Explaining Life's Complexity, Darwinists and Doubters Clash
For example, while Dr. Behe and other leading design proponents see the blood clotting system as a product of design, mainstream scientists see it as a result of a coherent sequence of evolutionary events.

Early vertebrates like jawless fish had a simple clotting system, scientists believe, involving a few proteins that made blood stick together, said Russell F. Doolittle, a professor of molecular biology at the University of California, San Diego.

Scientists hypothesize that at some point, a mistake during the copying of DNA resulted in the duplication of a gene, increasing the amount of protein produced by cells.

Most often, such a change would be useless. But in this case the extra protein helped blood clot, and animals with the extra protein were more likely to survive and reproduce. Over time, as higher-order species evolved, other proteins joined the clotting system. For instance, several proteins involved in the clotting of blood appear to have started as digestive enzymes.

By studying the evolutionary tree and the genetics and biochemistry of living organisms, Dr. Doolittle said, scientists have largely been able to determine the order in which different proteins became involved in helping blood clot, eventually producing the sophisticated clotting mechanisms of humans and other higher animals. The sequencing of animal genomes has provided evidence to support this view.

For example, scientists had predicted that more primitive animals such as fish would be missing certain blood-clotting proteins. In fact, the recent sequencing of the fish genome has shown just this.

"The evidence is rock solid," Dr. Doolittle said.

The theory has unlocked many of the mysteries of the natural world. For example, by studying the skeletons of whales, evolutionary scientists have been able to trace the history of their descent from small-hoofed land mammals. They made predictions about what the earliest water-dwelling whales might look like. And, in 1994, paleontologists reported discovering two such species, with many of the anatomical features that scientists had predicted.

Intelligent design proponents are careful to say that they cannot identify the designer at work in the world, although most readily concede that God is the most likely possibility. And they offer varied opinions on when and how often a designer intervened.

Dr. Behe, for example, said he could imagine that, like an elaborate billiards shot, the design was set up when the Big Bang occurred 13.6 billion years ago. "It could have all been programmed into the universe as far as I'm concerned," he said.

Note that the large amount of evidence supporting quantum mechanics also contradicts the idea that the universe is following some pre-programmed sequence of events.

But it was also possible, Dr. Behe added, that a designer acted continually throughout the history of life.

There have been no observations to support this idea either. If someone was actively tinkering on a large scale, we would see correlations in observations that could not be explained by science. We see no such correlations.

Dr. Behe, however, said he might find it compelling if scientists were to observe evolutionary leaps in the laboratory. He pointed to an experiment by Richard E. Lenski, a professor of microbial ecology at Michigan State University, who has been observing the evolution of E. coli bacteria for more than 15 years. "If anything cool came out of that," Dr. Behe said, "that would be one way to convince me."

Dr. Behe said that if he was correct, then the E. coli in Dr. Lenski's lab would evolve in small ways but never change in such a way that the bacteria would develop entirely new abilities.

In fact, such an ability seems to have developed. Dr. Lenski said his experiment was not intended to explore this aspect of evolution, but nonetheless, "We have recently discovered a pretty dramatic exception, one where a new and surprising function has evolved," he said.

Dr. Lenski declined to give any details until the research is published. But, he said, "If anyone is resting his or her faith in God on the outcome that our experiment will not produce some major biological innovation, then I humbly suggest they should rethink the distinction between science and religion."

Dr. Behe said, "I'll wait and see."


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