Comment: Borehole fossils may fill the gap

HOW our ancestors came out of the swamps and adapted to life on land some 360 million years ago is still poorly understood, despite what adverts for Irish Stout may suggest.

We don’t know how lungs, ears and other adaptations for land evolved, although it appears legs evolved in the water. The main reason for this is a gap in the fossil record covering this critical interval in our evolution. Known as Romer’s Gap, it is a 20 million year blank spot in the story of evolution.

In the next four years we hope to shine a torch on this pivotal stage in the evolution of life. To help us understand the evolution of fossils being discovered, the context of the sedimentary rock they were found in has to be understood. This is why the sequence is being drilled.

In some ways it is similar to what an archaeologist does; an ancient piece of jewellery may be interesting on its own, but only by understanding the buildings and layers it was found in can you work out how old it was and what it may say about the people who may have owned it.

The same is true of geology. By understanding the sedimentary rocks the fossils were found in we can firstly work out fundamental things like which fossil is older than another. This will then allow us to track the evolutionary changes as these creatures adapted to life on land.

Secondly, through reading the rocks we can understand the environment in which these vertebrates were living, and how it changed through time. This may help explain why they came on to land rather than just how.