Evolutionary grains of sand

Evolutionary ecologists are using “grains of sand” to understand more about evolutionary processes.

Dr Thomas Ezard from the University of Southampton is studying the fossils of microscopic aquatic creatures called planktonic foraminifera. The creatures are often less than a millimetre in size and can be found in all the world’s oceans. The remains of their shells now resemble grains of sand to the naked eye and date back hundreds of millions of years.

Ezard said: “Because planktonic foraminifera have been around for many millions of years and rocks containing groups of their species can be dated precisely, we can use their fossils to see evidence of how species evolve over time. We can also see how differences between individual members of species develop and, in theory, how a new species comes into existence.”

Ezard’s work which was conducted with colleagues Dr Gavin Thomas from the University of Sheffield and Professor Andy Purvis from Imperial College London furthers the debate on the best way to understand speciation.

The debate concerns whether fossil records such as those of planktonic foraminifera contain useful evidence of speciation over and above the molecular study of evolution. Traditionally, molecular evolution has used evidence from species that are alive today to determine what their ancestors may have looked like, whereas Ezard’s research promotes the importance of fossil records and using them in conjunction with molecular models.

One controversial hypothesis about speciation is that it provokes a burst of rapid genetic change – it is, however, difficult to detect new species accurately without fossil data.

The paper highlights the importance of using fossil and molecular evidence to study evolution. The paper’s authors hope that the use of both types of data will become widespread in the future study of evolution.

The research is detailed in Methods in Ecology & Evolution.