Why do birds have wings?

Birds are known to have it evolved from dinosaursbut statistical analyzes of upper limb joints preserved in fossils show that their wings did not come from a group Bird dinosaurs (the transitional group between dinosaurs and birds).

Thanks to studies of dinosaurs, many characteristics of current birds have been deduced, such as feathers or bone structure. But there is something Curiosity aroused Researcher in the Department of Earth and Planetary Sciences University of Tokyo: muscle

reproduction

There is a muscle It connects the shoulder and wrist of the wing From the bird of this structure is called spread and Help flutter, making the flight possible. Associate prof Tatsuya HirasawaThis, he explained in a statement, “is not found in other vertebrates.” In addition, it has lost its function in flightless birds – which is why it is known to be essential for flight.

The teacher says that for his understanding How did the trip develop? the birds One had to first understand how reproduction evolved: “This is what prompted us to explore some of the distant ancestors of modern birds, Theropod dinosaurs“.

How do they go from having arms to wings?

Theropod dinosaurs existed The arms are short -wingless – with three functional fingers, like Tyrannosaurus rex or Velociraptor. The scientists’ goal is to find evidence of A An early example of breeding In these dinosaurs to explain how the branch of birds moved from the arms to the wings.

But it is not a simple thing, because this muscle consists of Soft tissues that do not ossify well Or they didn’t, so no direct evidence was found. Therefore, the researchers had to find a file indirect way To determine whether or not there is a spread.

“Our solution to assessing the presence of symbionts is to collect data on joint angles along the arm or wing length of a dinosaur or bird,” he explains. Eureka Onea graduate student in Hirasawa’s lab.

The wings of modern birds are unable to fully extend due to this muscle, which “limits the range of angles possible between the connecting sections.” What they are looking for is Find a similar set of angles between dinosaur joints. Thus, “we will be sure that they also have a spread.” By analyzing the fossilized stances of birds, not dinosaurs, you can find ranges that “tell” about “expected” angles.

You know when, but not how or why

Following this pretext, they discovered that muscle may have evolved from a group manirraptor theropod dinosaur Like Velociraptor. This conclusion was supported when the researchers identified reproduction in Preserved soft tissue fossils in samples prior to flight evolution.

This means that you already know when the muscle arose, but not yet known how. Why these species need such a structure is a difficult question to answer. However, scientists have begun to explore pPossible links between fossil evidence and embryonic development modern vertebrates hoping to shed some light on this issue.

The team believes that some theropods could have evolved spread because their forelimbs were made so grab things Not for the purpose of flying.