Gaining Ground

"The story of vertebrates — fish, amphibians, reptiles, birds and mammals — resonates with many people more than do the stories of plants or invertebrate animals. How did animals first come out on to land and what were they like? It is clear that there was some considerable time between when plants spread across the landscape and when amphibians made the first tentative steps to move into this vegetated landscape. In this most absorbing book, Jenny spends some time discussing how the earliest vertebrates came out on to land. However, for me the most interesting part was in the Carboniferous Period, some 325 million years ago, when we encounter a wide range of small tetrapods, many of which were discovered at East Kirkton, near Edinburgh in Scotland. This is where my own story and Jenny’s intersect, as well as our books. In Burning Planet, I discuss some of the charcoal I found in rocks of this period across Scotland. I had been helped in some of my early excavations by a local man named Stan Wood. Stan had first found extraordinary fossils of early animals in a dry stone wall surrounding a football pitch during a half time break of a match at which he was the referee! This led him to explore a nearby quarry and to involve what is now the National Scottish Museum. I love this story as it shows how anyone, professional or amateur, with a passion for fossils can find amazing things at any time of life. The excavation of the site became an international multidisciplinary affair and I was tasked at coordinating studies of the fossil plants and even named one Stanwoodia, after Stan. However it was the animals that received the most attention with one Westlothiana being heralded as the first reptile. Jenny has spent over 20 years describing the animals from the site and she relates this with great clarity in her book that is now in its second edition. She has been able to show that many of these animals belong to basal stem groups but were very diverse. Jenny Clack highlights another locality that plays a significant role in tetrapod evolution at Joggins in Nova Scotia, where one of the first clearly reptilian tetrapods were first found by William Dawson and Charles Lyell in the 1850s within tree stumps. As I document in Burning Planet, these were also associated with charcoal and fire again may have played a significant role on the ecosystems where they were living. Fire and also partly responsible for their ultimate preservation. What becomes clear is that we should consider the evolution of the whole ecosystem and not just a part. One significant difficulty is that whereas many of the animals from this period of time have been reconstructed, many of the plants have not, and this leads to a problem of how to represent the animals within the correct landscape. This is a story that will run and run."