the "Molecular Clock" theory

The "Molecular Clock" theory suggests that genetic mutations accumulate in species' DNA at a relatively constant rate over time. By comparing DNA sequences of different species, scientists can estimate how long ago they shared a common ancestor—similar to using a clock that measures evolutionary time. This method relies on the idea that, despite natural variations, the overall rate of genetic change remains steady enough to provide a useful timeline for evolutionary events. It’s a valuable tool for understanding the history of life and how species are related.