Many scientists and philosophers of science are troubled by the relative isolation of developmental from evolutionary biology. Reconciling the science of development with the science of heredity preoccupied a minority of biologists for much of the twentieth century, but these efforts were not corporately successful. Mainly in the past fifteen years, however, these previously dispersed integrating programmes have been themselves synthesized and so reinvigorated. Two of these more recent synthesizing endeavours are evolutionary developmental biology (EDB, or "evo-devo") and developmental systems theory (DST). While the former is a bourgeoning and scientifically well-respected biological discipline, the same cannot be said of DST, which is virtually unknown among biologists. In this review, we provide overviews of DST and EDB, summarize their key tenets, examine how they relate to one another and to the study of epigenetics, and survey the impact that DST and EDB have had (and in future should have) on biological theory and practice.

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Kim, H. T., Olson, W. M. & Hall, B. K. 2009. Effects of hind limb denervation on the development of appendicular ossicles in the Dwarf African Clawed Frog, Hymenochirus boettgeri (Anura: Pipidae). -Acta Zoologica (Stockholm) 90: 352-358 Sesamoids and other appendicular ossicles are common in other classes of vertebrates but comparatively rare in amphibians. The pipid frog Hymenochirus boettgeri (Boulenger, G. A. 1899. On Hymenochirus, a new type of aglossal batrachians. -Annals of the Magazine of Natural History Series 7: 122- 125) is unusual among anurans in having seven (or more) appendicular ossicles in each hind limb. Sesamoids are often associated with muscles and tendons, and their development is usually regarded as mediated by or correlated with function. This study investigated the effects of paralysis (loss of function) on development of ossicles in the hind limb of Hymenochirus. Complete denervation of the right sciatic nerve was performed at developmental stages 63 and 66, and the animals maintained for a further 6-7 or 12-13 weeks. Specimens were cleared and double stained for cartilage and bone. There were no gross morphological differences between control and sham operated groups. The lunulae were not affected by paralysis, whereas the fabella arose later and/or regressed in some specimens. The distal os sesamoides tarsalia (OST) was shorter in paralysed individuals, and both the distal OST and cartilagines plantares showed delayed maturation. Denervation of the hind limb thus affected the timing of appearance, maintenance and rate of maturation of some sesamoid bones in Hymenochirus, but had no effect on others.