Theses on the semiotic study of life as presented here provide a collectively formulated set of statements on what biology needs to be focused on in order to describe life as a process based on semiosis, or signaction. An aim of the biosemiotic approach is to explain how life evolves through all varieties of forms of communication and signification (including cellular adaptive behavior, animal communication, and human intellect) and to provide tools for grounding sign theories. We introduce the concept of semiotic threshold zone and analyze the concepts of semiosis, function, umwelt, and the like as the basic concepts for theoretical biology.