This paper describes a new standpoint to further understanding the evotvability of A-life systems, that is, quantification of the dependency of system constituents. If a system exhibits evolutionary activity, new events, including the development or extinction of systems constituents, may emerge one after the other. The occurrence of new events would involve a changing complexion in the course of the future direction of system behaviors. In this respect, there have been a considerable number of studies on captunng longterm dynamics in A-life systems in terms of, for example, population dynamics. On the other hand, we focus on the quantification of relational concepts between constituents to clarify the occurrence of fundamental events affecting longterm course of evolution. We apply a quantification method to our A-life simulation model. Sequential analysis of the obtained resulLs enables us to visualize its long-term evolutionary dynamics. We discuss the effectiveness of our approach and the quantified evolutionary dynamics.