Wednesday, 15 December 2021

Shrinking dinosaurs became modern birds

It's known that modern birds evolved from dinosaurs, but a study published in the journal Science shows that the key to this transformation was, for one group of giant lizards called theropods, to continually get smaller and smaller over a 50-million-year time span.
Researchers present a detailed family tree of these dinosaurs and their bird descendants which maps out this transformation. They showed that the branch of theropod dinosaurs which gave rise to modern birds were the only dinosaurs that kept getting smaller. These bird ancestors also evolved new adaptations four times faster than other dinosaurs.
Being smaller and lighter in the land of giants, with rapidly evolving anatomical adaptations, these bird ancestors grew the ability to climb trees, glide and fly. Ultimately, this evolutionary flexibility helped birds survive the meteorite impact which killed off all their dinosaurian cousins.
Paleontologists looking at fossils of meat-eating dinosaurs, particularly those that were small bipedal like the Veloceraptors, have pointed out how they share an uncanny number of traits with modern birds: everything from wishbones, light hollow skeletons and three-fingered hands that folded like bird wings to an array of bright, complex feathers. Many of them also had some ability to glide, perhaps even fly.