Two recent papers, one on the plumage patterns in birds and the other on dinosaur "morphodynamics," present a powerful critique of the prevailing interpretation of evolution.

Interpretations of the fossil record and the relations among animals have changed radically over the past several centuries. So, too, has the meaning of the word, "evolution." Reflecting upon some of these changes can help to loosen our thinking from particular formulations that have tended over time to become unhealthy dogma.