How ear bones evolved

E VOLUTION HAS NO foresight. Biologists call this preadaptation, and it seems to explain the existence of three small bones, known as ossicles, that are found in the ears of mammals. Ossicles evolved from jaw bones, and the fossil evidence indicates this happened three times. And a newly discovered Cretaceous mammal called Jeholbaatar kielanae may help explain why. It suggests that the ossicles’ precursors became detached from the other jaw bones as a result of the way, indicated by the shape of those other bones, that Jeholbaatar kielanae chewed its food.