New ways of understanding evolution
Evolutionary ecologist Dr Thomas Ezard has entered into the debate on the best way to understand the process of the evolution of species – whether scientists should examine fossil records or molecular evidence of change.
An article authored by the University of Southampton researcher has been accepted for a special issue [ET1] [KW2] of the journal Methods in Ecology & Evolution in August 2013; a photograph of the creatures he researches will be on the cover.
Thomas is investigating evolution through the fossils of microscopic aquatic creatures called planktonic foraminifera, often less than a millimetre in size, which can be found in all of the world's oceans. The remains of their shells now resemble grains of san d [ET3] to the naked eye and date back hundreds of millions beyond the days of the dinosaurs. Of the 210 described species since the extinction of the dinosaurs, around 32 are alive today.
He holds an Advanced Fellowship from the Natural and Environmental Research Council (NERC) to lead this interdisciplinary research at Southampton into the differences between individuals in species and uses mathematical and statistical models [ET4] to analyse the changes over millions of years.
Thomas hopes to prompt discussions among scientists in his field through the paper. "The controversial hypothesis we test is that the processes leading to the formation of a new species (speciation) themselves provoke a short, sharp burst of rapid genetic change. This is controversial because it is hard to count all the historical speciation events without fossil data because all the extinct ancestors are missing," he says.
"We show, for the first time, how speciation counts from fossil evolutionary species correlates significantly with the rate of molecular evolution, unlike a similar approach using only modern species. One way of explaining this result is because the fossil counts are, for this group, a more accurate record of the number of speciation events in deep time."
Evolution within species and the formation of new species is a key part of evolutionary biology, but one for which lots of data are rare. The rich fossil record of these organisms means they are a good candidate to link fossil evidence with data on molecular diversification. Unifying these two fields is the goal of the journal's special issue.