Abstract
This paper discusses the differential distribution of opportunities for professional development of science teachers in post-apartheid South Africa. It is argued that northern/western ideas about teacher change and development are poorly suited to modelling practices and challenges for those who were historically disadvantaged. The environment in which teachers work-physical, social and political-act to select a more limited repertoire of behaviour than those providing in-service might imagine. The paper proposes that evolutionary ideas on teacher change and development offer a more effective model of the constraints under which teachers work. These ideas have general application to educational systems in sub-Saharan Africa. The implications for policy are a need to research current practices more thoroughly and to facilitate change through modest steps.