In this paper, we describe the Jack-in-the-Net (Ja-Net) architecture for adaptive services in a large scale, open network environment. Using biologically inspired concepts, Ja-Net achieves built-in capabilities to create/emerge services adaptively according to dynamically changing network conditions and user preferences. In Ja-Net, a service is implemented by a collection of autonomous system components called cyber-entities. Cyber-entities are autonomous with simple behaviors and interact with each other using Ja-Net ACL (Agent Communication Language) to jointly provide a service. For instance, cyber-entities migrates from node to node and find a new cyber-entity to interact with. Also, cyber-entities may establish relationship with interaction partners to form a group to provide a service. Strength of relationship between cyber-entities is a measure for the usefulness of the relationship and is adjusted based on the level of satisfaction indicated by a user who received the service...