How Good is the Fossil Record and Does it Give a Balanced History of Life?

How useful is the fossil record? This is a question that has long-plagued researchers studying evolution and past species. Now, scientists are questioning whether the fossil record can actually give a balanced view of the history of life, or if it's too biased.

In this latest study, the researchers turned to the rich and well-studied fossil record of Great Britain. Over 200 years, scientists have amassed enormous detailed knowledge about the rocks and fossils of the islands. In this case, the scientists compared biodiversity through the last 550 million years of the British fossil record against a number of geological and environmental factors, including the area of sedimentary rock, the number of recorded fossil collections and the number of named geological formations.

In the end, the scientists found that out of all the geological factors, only the area of preserved rock drives biodiversity. This means that other factors, such as counts of fossil collections and geological formations, are not independent measures of bias of the fossil record.

"We suspected that the similar patterns displayed by the rock and fossil records were due to external factors rather than the number of fossils being simply dictated by the amount of accessible rock," said Alex Dunhill, one of the researchers, in a news release. "Our work shows this is true. Factors such as counts of geological formations and collections cannot be used to correct biodiversity in the fossil record."

What does this mean? The findings fundamentally alter the way we view the diversity of life through time. More specifically, it shows that both the preservation of rock and fossils were probably driven by external environmental factors like climate change and sea level. This actually helps explain similarities between rock and fossil records.

"Paleontologists are right to be cautious about the quality of the fossil record, but perhaps some have been too cautious," said Michael Benton, co-author of the new study. "The sequence of fossils in the rocks more or less tells us the story of the history of life, and we have sensible ways of dealing with uncertainty. Some recent work on 'correcting' the fossil record by using formation counts may produce nonsense results."

The findings are published in the journal Nature Communications.