Earth Science, Earth's System, ES 1: Materials/Energy Flow (MS), ES 3: Earth's Resources (MS), HE 1: Plate Tectonics (HS), HE 2: Early Earth (HS), HE 2: Geoscience (MS), HE 3: Stratigraphic Records (MS), History of Earth

Coal Formation Not Correlated with Fungal Evolution

Delayed fungal evolution did not cause the Paleozoic peak in coal production

SUMMARY: This article provides evidence to refute the theory that most of our coal was formed during a period of time (Carboniferous-Permian age, about 299 million years ago) when fungus had not evolved enzymes to digest lignin. Plant material was thought to have died and not decayed, eventually turning into large amounts of coal. The first piece of evidence points out issues with previous research. The second piece of evidence talks about the existence of fungal enzymes able to break down lignin before the Permian age. The third piece of evidence looked at the inconsistency between rates of accumulation of dead trees and the amount of coal produced. Finally, the authors looked at the climate and tectonic plate movements during the Permian age and provided the last piece of evidence that the massive amounts of coal produced was most likely due to a combination of humid climate, wetlands created by glaciers, tectonic plate movement that buried a lot of the organic material, and some contributions from lack of decay.

LESSON COMMENTS: A lot of times, popular ideas in science are presented by journalists and news outlets as if they are fact. This isn’t an easy paper to read, but the evidence in this paper should be shared/discussed with students to illustrate the necessity for skepticism and being open-minded to new ideas and theories. Discussions can include topics such as:

  • How much evidence do you need to have a well supported theory?
  • Why should methodology be carefully analyzed when reading a paper?
  • Why is it important to replicate other people’s experiment?

Nelsen, M. P., DiMichele, W. A., Peters, S. E., & Boyce, C. K. (2016). Delayed fungal evolution did not cause the Paleozoic peak in coal production. Proceedings of the National Academy of Sciences of the United States of America, 113(9), 2442-7.