Until very recently, one of the biggest myths in science was that all dinosaurs have been extinct for the past 65 million years. But thanks to new fossil discoveries that filled in our knowledge about avian dinosaurs, we now know that only some dinosaurs went extinct following an asteroid collision with Earth - others survived and gave rise to the birds we live with today.
To figure out how this evolution occurred, researchers in Chile have manipulated the genes of regular chickens so they develop tubular, dinosaur-like fibulas on their lower legs - one of the two long, spine-like bones you’ll find in a drumstick.
In avian dinosaurs such as the Archaeopteryx, the fibula was a tube-shaped bone that reached all the way down to the ankle. Another bone, the tibia, grew to a similar length alongside it.
As evolution progressed through to a group of avian dinosaurs known as the Pygostylians, the fibula became shorter than the tibia, and sharper and more splinter-like towards the end, and it no longer reached the ankle.
While modern bird embryos still show signs of developing long, dinosaur-like fibulae, as they grow, these bones become shorter, thinner, and also take on the splinter-like ends of the Pygostylian bones, and never make it far enough down to the leg to connect with the ankle.
Source:http://www.sciencealert.com/scientists-have-grown-dinosaur-legs-on-a-chicken-for-the-first-time
Watch:https://www.youtube.com/watch?v=0QVXdEOiCw8
No comments:
Post a Comment