Ammonite fossils preserved in limestone. Such fossil deposits help scientists to understand biodiversity over Earth’s history. Credit: Herve Conge/SPL

Large language models (LLMs), such as the one underlying OpenAI’s ChatGPT, are trained to recognize patterns in written texts, helping them to choose a statistically probable word to complete a sentence. Palaeontologists have now trained a similar model on fossil records instead of words, then used it to reconstruct a timeline of changes in Earth’s biodiversity over hundreds of millions of years in unprecedented detail.

This big-data approach to interpreting the rock record — the field known as stratigraphy — could spur a rethink of major upheavals in the history of life, the model’s developers say.…