'Dinosaurs evolved into birds,' is a controversial theory that has been considered by scientists for after the discovery of the first dinosaur-bird fossil. But how dinosaurs eventually evolved into the modern version of the bird, is still unconfirmed.
The theory comes a bird-like dinosaur Archaeopteryx, which was discovered in 1861, but how the evolution actually occurred is still debatable. A group of researchers from the University of Beijing might have the answer.
The group of scientists stressed on the fact that natural selection works in one primary way - it emphasizes on existing features rather than creating new ones from scratch. This remains true of dinosaurs. In pre-historic times, certain dinosaurs had two feet, and two additional wings, which was the closest resemblance to modern birds as it gets.
To further test how these wings worked, as dinosaurs were certainly much larger than birds, scientists decided to perform a study on an ostrich.
An ostrich certainly can't fly, but can it attempt to fly, is what the scientists essentially tested.
In a study published in the PLOS Computational Biology, mechanical engineer Jing-Shan Zhao put a set of fake, mechanical wings on an ostrich to test if the bird involuntarily moved its wings while running. It did.
While the ostrich didn't really take off the ground, the theory certainly did. Scientists used this instance to argue that when Caudipteryx ran, its mini-wings flapped involuntarily. The dinosaur's descendants would have also harnessed this trait to take off from the ground for the first time, the researchers proposed.
The Caudipteryx was a dinosaur that lived about 125 million years ago, and walked on two legs and bore a pair of feathery 'proto-wings' similar to the mechanical ones on the ostrich.
But it wasn't only the ostrich they used to back-up this theory. They also created a robot-dinosaur, and ran it on a treadmill.
The group used fossil analyses to develop a real-life mathematical structure model of the dinosaur. Then, they simulated running motion, to calculate how the other parts of the dinosaur's body reacted. They found that at a fast enough speed, between 5.5 and 12.9 miles per hour, the dinosaur's wings flapped. This speed could easily have been recreated by the original dinosaur, Caudipteryx, and the similar situation is what is the researchers presume happened.
Combining these two tested out instances, the researchers proposed the theory of how dinosaurs actually took flight, and eventually evolved into birds.