Monday, February 27, 2006

Beaver Changes Everything 

What science does:
The remarkable fossil bones of a fur-covered, swimming mammal that lived in the age of the dinosaurs 164 million years ago have been discovered in China, raising a wave of excitement among scientists whose timetable for mammalian evolution has just been pushed back by 100 million years.

The animal appears to have been more than a foot long and weighed nearly 2 pounds, with a tail remarkably like a beaver and seal-like teeth clearly adapted for catching and eating fish, its discoverers say.

But what's most intriguing is that, until now, most scientists have thought that when dinosaurs ruled the Earth the only mammals around were primitive little creatures no bigger than rats or shrews. They were thought to subsist mostly on insects and plants, and larger, more diversified mammals evolved only later after the dinosaurs became extinct some 65 million years ago.

The new discovery puts that idea to rest . . . .

"We stand at the threshold of a dramatic change in the picture of mammalian evolutionary history, and many chapters of it will soon need rewriting," said Thomas Martin, a paleontologist at the Research Institute of the famed Senckenberg Museum in Frankfurt, Germany, who commented on the report for Science . . . .

"This exciting fossil is a further jigsaw puzzle piece in a series of recent discoveries demonstrating that the diversity and early evolutionary history of mammals were more complex than perceived less than a decade ago," Martin wrote.

And it "impressively contradicts" earlier views that the earliest ancestors of modern mammals were "generally primitive and unspecialized," he said.
New evidence turns up -- solid evidence that happens to contradict the current scientific orthodoxy. So what happens? Is the evidence suppressed, denied, ridiculed? Nope. The orthodoxy changes to encompass it. This is why so-called paradigm shifts take place with such extraordinary rapidity. Scientists are quick to embrace revolutionary ideas such as evolution or relativity because of their enormous explanatory power: the new way of looking at the physical world makes more sense, and more consistent sense, of observable phenomena.

Religion, on the other hand, insists on "adjusting" the physical world to fit the Procrustean bed of dogma. And the religious mindset, alas, is not confined to religion:
Oregon State University scientists reported in Science magazine that some logging practices may contribute to forest fires, rather than curbing them as conventional wisdom leads us to believe. The report ran contrary to current federal policy under the Bush administration, and the funding for the research group was suspended . . . .

Fortunately, the federal agency involved restored funding rapidly after an outcry by some members of Congress. Still, a hearing was held on the issue last Friday, where the main topic seemed to be how to best discredit the study’s primary author.
When you hear the increasingly common claim that evolutionary biology is "just another religion," you may safely assume that the speaker is A) devoutly religious, B) woefully ignorant of science, and C) full of squirrel shit. We suspect our learned colleague P.Z. Myers of Pharyngula might join us in recommending that those who reject the notion of evolution should also, as a matter of simple consistency, reject the notion of medicine:
The narrowness of the birth canal, the existence of wisdom teeth, and the persistence of genes that cause bipolar disease and senescence all have their origins in our evolutionary history. In a whole array of clinical and basic science challenges, evolutionary biology is turning out to be crucial. For example, the evolution of antibiotic resistance is widely recognized, but few appreciate how competition among bacteria has shaped chemical weapons and resistance factors in an arms race that has been going on for hundreds of millions of years. The incorrect idea that selection reliably shapes a happy coexistence of hosts and pathogens persists, despite evidence for the evolution of increased virulence when disease transmission occurs through vectors such as insects, needles, or clinicians' hands. There is growing recognition that cough, fever, and diarrhea are useful responses shaped by natural selection, but knowing when is it safe to block them will require studies grounded in an understanding of how selection shaped the systems that regulate such defenses and the compromises that had to be struck . . . .

The triumphs of molecular biology call attention to evolutionary factors responsible for certain genetic diseases. The textbook example is sickle-cell disease, whose carriers are resistant to malaria. Similar protection against infection has been hypothesized for other disorders. Which aspects of the modern environment are pathogenic? We need to find out. Increases in breast cancer have been attributed to hormone exposure in modern women who have four times as many menstrual cycles as women in cultures without birth control. Other studies suggest that nighttime exposure to light increases the risk of breast cancer by inhibiting the normal nighttime surge of melatonin, which may decrease tumor growth. Evolution has also provided some explanations for conditions such as infertility. The process that eliminates 99.99% of oocytes may have evolved to protect against common genetic defects. And some recurrent spontaneous miscarriages may arise from a system evolved to protect against investing in offspring with combinations of specific genes that predispose to early death from infection.
TANGENTIALLY RELATED SIDEBAR (also courtesy of P.Z. Myers): We thought we had met our religion-bashing quota for the evening, but upon re-reading the post above we realized we had neglected to include any outright blasphemy. If you are distressed by the possibility that you might one day go to heaven, where you will never see any of your more entertaining friends, take out a little insurance policy by clicking here.

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