Darwin Feared Fossil Gaps Would Break His Theory — Science Just Proved Him Wrong

New research shows that the gaps in the fossil record, once a major concern for Charles Darwin, do not significantly impact our ability to reconstruct the history of life on Earth

My college years were some of the most transformative in my life. After years of curiously reading about biology, evolution, and paleontology in the non-technical media, I was gaining the knowledge to understand the scientific literature.

However, I soon realized I was privileged. Because of the year I was born, I could learn a well-documented and studied science. One of the things that fascinated me the most was that naturalists in the 1800s came up with evolutionary and natural history theories that still stand today using only sparse and not easily available data. Nothing else. What a vision!

For example, when Charles Darwin published On the Origin of Species in 1859, only a small fraction of the fossil record as we know it today had been documented. In fact, it’s estimated that less than 1% of the current known fossil species were identified at the time. The field of paleontology was still in its early stages, and major fossil discoveries — like those of dinosaurs, early mammals, and many ancient marine life forms — were yet to come.

By the mid-19th century, some important fossils were known, such as the discovery of Megalosaurus (one of the first dinosaurs to be scientifically described in the 1820s), but much of the fossil record, especially for earlier and more diverse life forms, remained undiscovered.

So my question was, how could Charles Darwin and his colleagues come up with the idea of natural selection and evolution with such sparse data? The answer? Well, they had some well-documented doubts and fears. Among them is whether we could make an accurate prediction of how life evolved given the information at hand.

But why are fossils so important here? Fossils are one of our most valuable resources when understanding how life evolved on Earth. This is not just me trying to agree with my paleontologist wife; it is a fact. Fossils have helped us decipher multiple evolutionary histories, from birds coming from carnivorous dinosaurs to most modern groups of animals suddenly evolving 530 million years ago.

Thus, fossils offer snapshots of now-extinct creatures and ecosystems, letting us piece together the story of evolution. But there’s one problem that has always lingered in the background: the fossil record is incomplete.

Many fossils are lost to time due to erosion or never fossilized in the first place. Of course, this has led to concerns about whether we can truly trust what the fossil record tells us about how life evolved.

A new study, however, suggests that this issue might not be as big of a problem as previously thought. The research, led by Dr. Niklas Hohmann from Utrecht University, focuses on how gaps in the fossil record affect our understanding of evolution, particularly when studying carbonate platforms — regions where limestone and other carbonates accumulate over millions of years, often forming fossils. Regions that are very good at recording life through time in an almost continuous way.

The study’s findings indicate that even though fossils are often missing from these ancient rock layers, we can still accurately reconstruct evolutionary histories. But why?

The research used computer simulations to mimic how fossils might be preserved or lost over time within these carbonate platforms. In other words, they recreated different evolutionary scenarios.

By combining different evolutionary models — like stasis (where species don’t change much over time) and random walks (where species evolve gradually) — with simulations of how carbonate layers build up as sediment deposits, the team was able to see how well evolutionary patterns could be detected. Could we reconstruct these hypothetical evolutionary processes even when part of the fossil record gets lost?

One key finding was that the position of fossils within a carbonate platform (whether they were found closer to the shore or deeper in the sea) had only a small influence on the ability to recognize evolutionary trends.

So, what’s the real takeaway here? Dr. Hohmann and his team discovered that it’s not so much the overall incompleteness of the fossil record that matters, but rather how regular the gaps are. In the words of Hohmann, “It’s as if you are missing half of a movie. If you are missing the second half, you can’t understand the story, but if you are missing every second frame, you can still follow the plot without problems.”

This means that if the gaps in the fossil record occur at regular intervals, scientists can still make sense of evolutionary patterns, they can understand what’s going on. However, when gaps are too long or occur in irregular patterns, it can skew the results, making it harder to draw accurate conclusions. In other words, small, evenly spaced gaps are okay, but long, erratic gaps create a much bigger problem.

One of the more interesting findings from the study was how these gaps can actually change the way evolution appears to unfold. For example, gradual directional evolution, where species slowly evolve over time, is more susceptible to these gaps, sometimes making it seem like species evolved in short, rapid bursts instead.

This phenomenon, known as punctuated evolution, is when it looks like species stayed the same for long periods, only to suddenly evolve quickly — a pattern that may sometimes be an illusion caused by gaps in the fossil record. In contrast, stasis — where species remain largely unchanged — was not as affected by these gaps.

Another important point from the study is the idea of “maximum hiatus duration,” or the length of the longest gaps between fossil layers. Hohmann and his team found that longer gaps were more likely to distort our understanding of evolution than shorter, more frequent gaps. This insight is crucial because it helps paleontologists better understand which fossil records might give a clearer picture of evolution; and which should be scrutinized closely.

See this video below by Dr. Benjamin Burger at Utah State University if you want to have a better understanding of how paleontologists date rocks using fossils, so that you can see why this is important.

As I mentioned earlier, Charles Darwin himself recognized this problem, and worried that the fossil record wasn’t complete enough to show the gradual changes his theory predicted. He feared that the missing pieces in the fossil record would prevent us from truly understanding how species evolved.

However, according to this study, Darwin’s concerns, while legitimate, prove to be not as relevant as he thought. As Dr. Hohmann points out, “Our results show that this fear is unjustified. We have a good understanding of where the gaps are, how long they are, and what causes them. With this geological knowledge, we can reconstruct evolution hundreds of millions of years ago at an unprecedented temporal resolution.”

But most importantly, this research offers a reassuring message to those studying evolution: despite its gaps, the fossil record remains a reliable source of information about how species have changed over time. And by better understanding the structure of the gaps in the record, scientists can make more informed judgments about the evolutionary processes that shaped life on Earth.

What Darwin and his colleagues came up with, given the data that was available back then, is nothing short of a fascinating rationalization process. However, they would likely be relieved to know that their theory is still standing strong, even if we now have a more complete understanding of how things work, even in the face of an imperfect fossil record. That we can still trust the fossil record to tell us the story of life’s evolution — we just need to know how to interpret it.