"During the early evolution of these groups," Smith said, "there is the development of features that we often recognize to identify these groups visually, but they don't begin to speciate rapidly until after the development of the features."
"These findings are consistent with the view that radiations tend to be lit by a long 'fuse,' and also with the idea that an initial innovation enables subsequent experimentation and, eventually, the evolution of a combination of characteristics that drives a major radiation," the authors write.
Smith believes some triggers for the speciation explosion could have been internal, such as building a better flower or learning how to grow faster and thus outcompete other plants. The winning edge could also have come from the arrival of pollinating insects or changes in climate. The team plans to investigate these questions.
To compile the phylogenetic tree, the group combined data gathered from an exhaustive survey of the peer-reviewed literature with a gene-wide classification of species thanks to data gathered by GenBank, a genetic sequence database run by the U.S. National Institutes of Health.
"This is a nice example of how computer science and cyberinfrastructure initiatives can help to extend the limits of biological explorations," said Alexandros Stamatakis, group leader of the scientific computing group at the Heidelberg Institute.
|Contact: Richard Lewis|