Just like cooking spinach makes it easier to digest, some fungi can break down plant cell walls, including lignin. The short-order cooks of the natural world, they have an unheralded job making nutrients accessible to the rest of us. His research illustrated just how essential white rot fungi were to Earth's evolution.įungi are still indispensable. They found that, just as she predicted, a group of fungi known as "white rot fungi" evolved the ability to break down lignin approximately the same time that coal formation drastically decreased. Through evolutionary biology research supported by the Department of Energy's (DOE) Office of Science, Hibbett and his team confirmed her theory. She theorized that instead of ecosystem change alone, something else played a major role – something evolving the ability to break down lignin. An alternative theory from researcher Jennifer Robinson intrigued him. When the fossil record started showing trees breaking down around 300 million years ago, most scientists assumed it was because the ubiquitous swamps of the time were drying up.īut biologist David Hibbett at Clark University suspected that wasn't the whole story.
When a tree died, it just sank into the swamp where it grew. For millions of years, nothing could break down lignin, the strongest substance in those cell walls.
To prevent this gruesome fate, they developed extremely tough cell walls around 400 million years ago. Like most of us, trees don't want to be eaten alive. Anaerobic gut fungi colonize plant matter and release enzymes that break cell walls into simple sugars.