TALLAHASSEE, Fla. - Rodents can tell us a lot about the way species evolve after they move into new areas, according to a new and exceptionally broad study conducted in part by Florida State University biological science Professor Scott J. Steppan.
The study of the evolutionary history of rodents calls into doubt a generally held understanding that when a species colonizes a new region, such as a continent, evolution leads to a dramatic increase in the number and variety of species.
"Biological diversification, or adaptive radiation, is generally thought to be the major explanation for diversification across all of life," said Scott J. Steppan, a Florida State University professor of biological science. "One of the most fundamental questions in biology is why some groups of plants and animals have lots of species and others do not. To address this question, we developed the most comprehensive DNA-based family tree of the most evolutionally successful group of mammals the muroid rodents."
In the study, "Ecological Opportunity and Incumbency in the Diversification of Repeated Continental Colonizations by Muroid Rodents," published in the journal Systematic Biology, Steppan, John J. Schenk of Tulane University and Kevin C. Rowe of Victoria Museum, Australia, used the phylogeny, or evolutionary family tree, of these rodents to test whether the adaptive radiation model of biological diversification actually is as common as presumed.
In one of the most complex studies of the question in any group of organisms, the researchers demonstrated that muroids have colonized continents at least 28 times. Muroids include most of the species used in biomedical research, such as mice, rats, hamsters and gerbils.
When a species first colonizes a new area with no close competitors, biologists would expect the rate at which new species are created to increase rapidly. Then, adaptation into new niches should make the descend
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Florida State University