_Conjectures and Refutations_ is one of Karl Popper's most wide-ranging and popular works, notable not only for its acute insight into the way scientific knowledge grows, but also for applying those insights to politics and to history. It provides one of the clearest and most accessible statements of the fundamental idea that guided his work: not only our knowledge, but our aims and our standards, grow through an unending process of trial and error.

_Conjectures and Refutations_ is one of Karl Popper's most wide-ranging and popular works, notable not only for its acute insight into the way scientific knowledge grows, but also for applying those insights to politics and to history. It provides one of the clearest and most accessible statements of the fundamental idea that guided his work: not only our knowledge, but our aims and our standards, grow through an unending process of trial and error.

The origin of novel traits is what draws many to evolutionary biology, yet our understanding of the mechanisms that underlie the genesis of novelty remains limited. Here I review definitions of novelty including its relationship to homology. I then discuss how ontogenetic perspectives may allow us to move beyond current roadblocks in our understanding of the mechanics of innovation. Specifically, I explore the roles of canalization, plasticity and threshold responses during development in generating a reservoir of cryptic genetic variation free (...) to drift and accumulate in natural populations. Environmental or genetic perturbations that exceed the buffering capacity of development can then release this variation, and, through evolution by genetic accommodation, result in rapid diversification, recurrence of lost phenotypes as well as the origins of novel features. I conclude that, in our quest to understand the nature of innovation, the nature of development deserves to take center stage. BioEssays 30:432–447, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

Although the role of morphology in evolutionary theory remains a subject of debate, assessing the contributions of morphological investigation to evolutionary developmental biology (Evo-devo) is a more circumscribed issue of direct relevance to ongoing research. Historical studies of morphologically oriented researchers and the formation of the Modern Synthesis in the Anglo-American context identify a recurring theme: the synthetic theory of evolution did not capture multiple levels of biological organization. When this feature is incorporated into a philosophical framework for explaining the (...) origin of evolutionary innovations and novelties (a core domain of inquiry in Evo-devo) two specific roles for morphology can be described: (1) the conceptualization and operational identification of the targets of explanation; and (2) the elucidation of causal interactions at higher levels of organization during ontogeny and through evolutionary time. These roles are critical components of any adequate explanation of innovation and novelty though not exhaustive of the parts played by morphology in evolutionary investigation. They also invite reflection on what counts as an evolutionary cause in contemporary evolutionary biology. (shrink)