Abstract
This paper proposes an evolutionary development approach, which uses software product line and feature modeling concepts for evolving software requirements and architectures. The different versions of an evolutionary system are considered a software product line, with each version of the system a product line member. Requirements are modeled using both use case and feature modeling. Evolution is built into the software development approach because variability in the software architecture is determined by considering the impact of each variable feature on the software architecture and evolving the architecture to address new features. Being feature based, the approach closely relates the evolution of the software architecture to the evolution of software requirements, as well as providing traceability between requirements and architecture.