February 11, 2009

Flowering-plant burst fostered forests

A U.S. study suggests a burst of flowering plants 90 million years ago led to the formation of forests and similar evolutionary bursts in animals.

The University of Florida-led study was based on a DNA analysis of living flowering plants. Researchers determined the burst of speciation during a 5-million-year span was one of three major radiations of flowering plants, known as angiosperms.

The study focused on diversification in the rosid clade, a group with a common ancestor that now accounts for one-third of the world's flowering plants, the researchers said, noting the forests that resulted provided the habitat that supported later evolutionary diversifications for amphibians, ants, placental mammals and ferns.

Shortly after the angiosperm-dominated forests diversified, we see this amazing diversification in other lineages, so they basically set the habitat for all kinds of new things to arise, said Pamela Soltis, study co-author and curator of molecular systematics and evolutionary genetics at the Florida Museum of Natural History. Associated with some of the subsequent radiations is even the diversification of the primates.

The scientists said their study is the first to show the evolutionary relationships of the plants and provide evidence for their rapid emergence and diversification.

The research is to appear in next week's online edition of the Proceedings of the National Academy of Sciences.