Two decades after the discovery of Zhenyuanlong, over 20 similar species were recovered. Using these newly found fossils, paleontologists generated a timeline that highlighted the evolutionary changes between each new species that eventually lead to the development of the structures seen in todays birds. Utilizing the discovery of the newly formulated evolutionary chain, scientists uncovered that these changes happened as a result of slow evolutionary progression. Similarly, with the discovery of the evolutionary chain, scientists could show when each morphological change occurred within a certain species. One characteristic that could be traced through fossil records is the development of the feather. Backtracking through this chain, researchers concluded that small dinosaurs resorted to small, puffy feathers to generate heat instead of using them for flight. As time progressed, these feathers started to grow longer until they resembled modern-day quilled …show more content…
Microraptor utilized its streamlined body and wings in order to glide which further support the theory that the evolution of dinosaurs led to birds. Similarly, the fossil record shows how early members of the theropod developed a wishbone chest, the fusing of both right and left collarbones, which allowed for the stabilization of the shoulders that allowed for higher shock absorbent. Furthermore, it shows how theropods utilized hollow bones to intake oxygen during inhalation and exhalation. Similarly, birds have duel purposes for their hollow bones as it allows them to intake oxygen during inhalation and exhalation to fuel their high energy lifestyle as well as allowing for their body to be as light as possible for sustained flight. By using this evolutionary chain developed after the discovery of these unknown fossils, one can see how the gradual evolution of dinosaurs lead to the development of birds. Overall, by using the fossil record created by finding dinosaurs similar to birds, Brusatte showed how dinosaurs underwent gradual evolution over a period of tens of millions of years to create the species we know today as