An asteroid impact 66 million years ago led to the extinction of many species, including dinosaurs, but some flying feathered dinosaurs survived and evolved into today's birds. However, a new study challenges the idea that the asteroid had a major impact on bird evolution. The study, published in the Proceedings of the National Academy of Sciences, suggests that birds began diversifying tens of millions of years before the asteroid's collision. The study used DNA analysis to reconstruct the family tree of birds and found that the major groups of birds were already diversifying steadily before and after the asteroid impact. While some scientists disagree with the study's conclusion, it highlights the ongoing debate about the timing of bird evolution and the impact of the asteroid on their development.