This thematic presentation will focus on the dynamics and variety of the processes of the becoming of various sign systems through which semiotic subjects interact within and with their natural and cultural surroundings. In particular, the range of topics to be presented could be clarified here by a twofold reference to the biological concept of ecology, popularized in the humanities in the context of interest in the dependencies between human subjects in their broadly understood environments. Firstly, the most important component of the ecology of the sign systems constitutes, in a metaphorical sense, living organisms using them to exchange information; in the case of the signs of culture, it is humans as individuals and groups, for whom these signs serve as means of communication. Secondly, shifting the attention from signs to living beings as their users, capable of reacting to stimuli, reproducing, growing, and adapting, and thinking and acting, all kinds of signs functioning at different levels of message transmission should be considered as their primary, semiotic ecology. Since the signs as such, being sent to and received from the environment by living beings, including humans, essentially vary in dependence on the biological complexity of their users and the type of relations connecting them with the world, they (the signs) not only differ in terms of their ecological-relational properties but also change according to the requirements and needs communication. Accordingly, variability of signs systems, subjective and intersubjective worlds created in multimodal interactions between semiotic subjects through signs will be discussed.