A groundbreaking study published in the Proceedings of the National Academy of Sciences unveils that modern birds began their evolutionary journey much earlier than previously thought, predating the extinction of dinosaurs.
Led by scientists from the Chinese mainland and the United States, researchers analyzed the genomes of 124 living bird species to construct an evolutionary tree for Neoaves, which comprises 95% of all modern birds.
Integrating fossil records, the team discovered that the primary bird lineages split into two distinct groups during the Late Cretaceous period, approximately 87 million years ago. One group evolved into land-based species, while the other gave rise to waterbirds, long before the catastrophic extinction event 66 million years ago that wiped out the dinosaurs.
This challenges the long-held belief that the demise of dinosaurs directly led to a rapid diversification of bird species. According to first author Wu Shaoyuan, a professor at Jiangsu Normal University, the extinction event had a minimal impact on the evolutionary trajectory of birds.
Additionally, the study found that a global warming event 55 million years ago played a crucial role in the evolution of modern seabirds, including penguins and seagulls. Co-author Zhou Zhonghe from the Institute of Vertebrate Paleontology and Paleoanthropology emphasized that the development of modern birds was a gradual process driven by natural selection, aligning with the diversification of other life forms like plants, mammals, fish, and insects.
These new insights offer a more nuanced understanding of bird evolution, highlighting the intricate and continuous nature of their development over millions of years.
Reference(s):
cgtn.com
