Fossils play a crucial role in piecing together the story of evolutionary history. However, not every plant or animal turns into a fossil, and many that do can be lost to natural processes like erosion, which destroys the rocks holding them. Consequently, we encounter gaps in the fossil record, leaving us with a lack of necessary information to completely reconstruct evolutionary history. Recently, a group of sedimentologists and stratigraphers from the Netherlands and the UK explored the impact of these gaps on our understanding of evolutionary history. To their surprise, they concluded that the incompleteness may not be as significant an issue as previously thought.
Fossils are essential for piecing together the evolutionary journey of life on Earth. Nonetheless, not every living organism becomes a fossil, and many that do go undiscovered due to factors like erosion that can destroy the rocks holding them. This leads to gaps in the fossil record, resulting in missing crucial data for our evolutionary reconstruction. Recently, a team of sedimentologists and stratigraphers from the Netherlands and the UK assessed how these gaps affect our understanding of evolutionary history. To their surprise, they found that these gaps may not be as problematic as expected. “It’s similar to watching a movie where you miss half of it. Missing the second half makes it hard to grasp the story, but if every other frame is missing, you can still figure out the plot without much trouble.”
According to Niklas Hohmann, a researcher at Utrecht University’s Faculty of Geosciences and leader of the study, “The predictability of the gaps, not the gaps themselves, dictates how we reconstruct evolutionary history. If there’s a lot of missing data but the gaps are consistent, we can still piece together evolutionary history fairly accurately. However, if the gaps are lengthy and inconsistent, our findings can become skewed.”
Darwin
Ever since Charles Darwin proposed his theory of evolution, scientists have seen the imperfections in the fossil record as a challenge to reconstructing evolutionary history. Darwin was concerned that the gradual changes his theory suggested would be obscured by the numerous gaps in fossils. “Our findings indicate that this concern is unfounded. We have a clear grasp of the gaps’ locations, lengths, and causes. With this geological insight, we can explore evolution from hundreds of millions of years ago with unprecedented accuracy,” states Niklas Hohmann.
Simulations
Advanced computer simulations of geological processes spanning greater timescales than recorded history can be useful to investigate the effects of these gaps. Hohmann and his team used simulations of various evolutionary processes alongside sediment deposits to evaluate how effectively evolutionary modes can be discerned from fossil time series. They also studied how the findings differ based on various positions within the carbonate platform and the different stratigraphic structures created by fluctuating sea levels. “If Darwin were to read this article, he would definitely feel reassured: his theory has withstood the unpredictable nature of the fossil record. Deep-time fossil information, despite its limitations, supports our comprehension of evolution’s pace and patterns.”
