Category: Articles

Evolution in a Petri Dish

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Yale Alumni Magazine, June 1, 2006

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Charles Darwin never thought he could witness evolutionary change. He relied instead on indirect clues. He looked at its effects after millions of years—in the fossil record and in the similarities and differences among living species. He got clues to the workings of evolution from the work of pigeon breeders, who consciously chose which birds could reproduce and thus created birds with extravagant plumage. But that was artificial selection—not natural selection that had been operating long before humans came on the scene. Darwin was pretty sure that natural selection worked too slowly for him or anyone else to witness.

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Bacterial Evolution in the Yogurt Ecosystem

Posted on by Lori Jia

The New York Times, May 30, 2006

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About 5,000 years ago, cattle herders discovered how to make yogurt. Scientists are now discovering that they also mounted an unplanned experiment in evolution.

Certain species of bacteria are responsible for turning milk into yogurt. As the microbes feed on sugar in the milk, they produce acidic wastes that cause the milk to clot. They also make the yogurt uninhabitable for other bacteria, preventing it from spoiling. And by breaking down some milk proteins into smaller pieces, they give yogurt its distinctive flavor.

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Humans May Have Limiting Effect on the Origin of (New) Species

Posted on by Lori Jia

The New York Times, May 23, 2006

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Humans can threaten species with extinction in many ways, including overfishing, pollution and deforestation. Now a pair of studies points to a new danger to the world’s biodiversity: humans may be blocking new species from evolving.

New species evolve when old species split apart. Animals living on a peninsula might become cut off from the mainland by rising sea levels, for example.

They would adapt to life on the island and acquire mutations not shared by the rest of their species. If the sea level should drop and the animals could mix together again, the mutations might make it less likely that the two populations could interbreed. They would be on their way to becoming separate species.

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Did DNA Come From Viruses?

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Science, May 12, 2006

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Scientists who deal in the history of life have never been quite sure what to do with viruses. One measure of their uncertainty is the Tree of Life Web Project, a collective effort to record everything known about the relationships of living and extinct species. The first page of its Web site—entitled “Life on Earth”—shows the broadest view: From a single root come three branches representing the domains of life (http://www.tolweb.org/).

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Starlings’ Listening Skills May Shed Light on Language Evolution

Posted on by Lori Jia

The New York Times, May 2, 2006

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The warbles and rattles of a starling seem innocuous enough. But starlings are now the object of a fierce debate about the nature of language.

In the current issue of Nature, scientists report that starlings recognize song patterns based on rules of the sort that make language possible. Their paper has drawn sharp reactions pro and con from linguists and animal communication experts.

The debate is over what, if anything, the results mean for human language. Some scientists believe that the findings offer new clues to how it evolved. Others dismiss the notion.

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