University of Chicago researchers play key roles in recent proofs of natural selection
December 31, 2008
University of Chicago scientists played a role in three of 15 studies highlighted by the journal Nature as "evolutionary gems," papers published in the journal in the last decade that demonstrate why scientists can confidently "treat evolution by natural selection, in effect, as an established fact."
As we approach the 200th anniversary of the birth of Charles Robert Darwin (12 Feb. 1809) and the 150th anniversary of his most famous work, On the Origin of Species (published 24 Nov. 1859), scientists consider evolution as a basis for their understanding of the world. But many scientists “may not be aware of the strong evidence that has accumulated in its favour,” says Philip Campbell, Editor-in-Chief of Nature. "In a year in which Darwin is being celebrated amid uncertainty or even hostility about his ideas among citizens, being aware of the incontrovertible evidence for those ideas is all the more important. We hope this document will help."
The Nature Web site will host this freely accessible resource, written by its staff, to explain the evidence for evolution by natural selection. The evidence is drawn from the fossil record, from studies of natural and artificial habitats, and from studies of molecular biological processes.
Gem #2, "from water to land," focuses on the discovery of Tiktaalik roseae--the intermediate fossil between fish and the first animals to walk out of water onto land 375 million years ago. Tiktaalik was discovered by a team led by Ted Daeschler, PhD, of the Academy of Natural Sciences, and Neil Shubin, PhD, of the University of Chicago and Field Museum and author of the best-selling book on evolution, Your Inner Fish.
First described in Nature in 2006, Tiktaalik had fish-like features such as a primitive jaw, fins and scales, as well as a skull, neck, ribs and parts of the limbs that are similar to four-legged land animals. The initial 2006 report focused on the transformation from fins to limbs, including the development of shoulder, elbow and wrist joints that were capable of supporting the animal's weight. In a 2008 paper, the researchers describe the animal's head and neck and show how Tiktaalik was gaining structures that could allow it to feed itself and breathe air.
Gem #8, "a case of co-evolution," focuses on a recent study that provided solid evidence for the Red Queen hypothesis, a theory proposed in 1973 by Leigh Van Valen, PhD, professor of ecology and evolution at the University of Chicago. Van Valen borrowed the title from Darwin's contemporary, Lewis Carroll. "It takes all the running you can do to keep in the same place," the Red Queen tells Alice in Through the Looking Glass (a sequel to Alice in Wonderland). "If you want to get somewhere else, you must run at least twice as fast as that."
In 2007, researchers from Belgium clearly documented evidence of such a co-evolutionary race, a prolonged series of mutational one-upmanship in which water fleas and a parasite that preys on them undergo tiny genetic adjustments that give them a slight temporary advantage, lasting until the other species can counter with its own evolutionary modification.
Gem #11, "evolutionary history matters," features a 2007 study from the University of California, Davis, of how moray eels--snake-like fishes that inhabit coral reefs--drag their prey into their gullet by using a second set of grasping jaws that they thrust forward from deep in their throat. In an editorial about the study in that same issue of Nature, Mark Westneat, PhD, curator of zoology at the Field Museum of Natural History in Chicago and lecturer in organismal biology and anatomy at the University of Chicago, places the discovery in perspective and suggests further studies to learn more about how this unusual feeding system evolved.
One year ago, an essay in Nature by Kevin Padian, president of the United States' National Center for Science Education, argued that "no individual has had such a sweeping influence on so many facets of social and intellectual life as Charles Darwin….Darwin moved intellectual though from a paradigm of unstable wonder at special creation to an ability to examine the workings of that natural world…in terms of natural mechanisms and historical patterns."
Despite Darwin's sweeping impact, "the concepts and realities of Darwinian evolution are still challenged, albeit rarely by biologists," notes the Nature press release. "A succinct briefing on why evolution by natural selection is an empirically validated principle is useful for people to have to hand…to illustrate the breadth, depth and power of evolutionary thinking."
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