Drawing from the concept of entropy in open systems theory, this article contributes to organizational theory by illuminating organizational life cycle theory and exploring open source software development communities (OSSDC) with quantitative longitudinal data. In particular, this study uses functional data analysis to uncover the development patterns of open source software projects in terms of effectiveness and activity levels. Our findings show that the life cycles of OSSDC display an inverted-U shape in terms of effectiveness level and an inverted-S shape in terms of activity level. Although our results provide some evidence of distinct states, they do not imply that such states are predetermined or irreversible. On the contrary, these numerous states are viewed here as intrinsically dynamic. These findings not only give empirical support to the organizational life cycle metaphor in the context of OSSDC, but also aid practitioners and policy-makers in assessing online communities. Taking an open systems view of organizations, this study aids in reconciling some issues in life cycle theory, such as the irreversibility and pre-determinacy of life cycle models, and adds to a young but fast growing stream of literature on open source projects. Lastly, our findings remark the importance of fostering active communities for superior effectiveness and long-term survival of the community.