Why do the best-known examples of evolutionary change involve the
alteration of one kind of animal into another very similar one, like the
evolution of a bigger beak in a bird? Wouldn't it be much more
interesting to understand how beaks originated? Most people would agree,
but until recently we didn't know much about such origins. That is now
changing, with the growth of the interdisciplinary field evo-devo, which
deals with the relationship between how embryos develop in the short
term and how they (and the adults they grow into) evolve in the long
term. One of the key questions is: can the origins of structures such as
beaks, eyes, and shells be explained within a Darwinian framework? The
answer seems to be yes, but only by expanding that framework. This book
discusses the required expansion, and the current state of play
regarding our understanding of evolutionary and developmental origins.