In this paper, we present a methodology to represent and measure knowledge which takes into account knowledge heterogeneity and its sectoral level theoretical and empirical implications in knowledge intensive environments. We draw on work on recombinant knowledge, extending the approach to include the way the dynamics of technological knowledge creation evolves according to a life cycle; testing the existence of concepts such as technological paradigms; mapping the characteristics of the search process in the phases of exploration and exploitation during this technology life cycle and detecting the differences in sectoral evolution that can be explained by the properties of the knowledge base. We use European Patent Office data (1981-2005) to propose some operational metrics for the knowledge base and its evolution in two knowledge intensive sectors: biotechnology and telecommunications. Our empirical results show that there are interesting and meaningful differences across sectors, which are linked to the different phases of the technology life cycles.