Jakob von Uexkull's Umwelt refers to an individual's model of reality, which is constructed by species-specific sentience and awareness.
For human beings, that model consists of physical objects (phenomena) and mental objects (noumena). For other organisms, it may consist of other things. There may even be more than just physical and mental things (unless you think that homo sapiens is the apex of evolutionary development and that its mind will never comprehend things which are currently unknown).
I think it's presumptuous to say: life evolved from non-life, or noumena arise from phenomena, either vice versa, or that both arise from something else entirely. Peirce held that phenomena and noumena are two aspects of one substance. I don't know enough to say even that, preferring to maintain my species-specific common sense, and only say that physical things and mental things exist.
Von Uexkull and Peirce never knew of each other's work, but Umwelt explains why Peirce could say, "...the entire universe...is perfused with signs, if it is not composed exclusively of signs", and why Niels Bohr could say, "We are suspended in language in such a way that we cannot say what is up and what is down." Because for human beings, that is how we interpret the world: through signs, language being a sign system. For human beings, there is no other reality but that which human sentience and awareness impose upon us.
Pansemiotics, being the study of everything semiosis, should not be relevant only to physics, but also to all other sciences (including psychology and sociology), as well as to culture (the mindset and products of a social group).
Also, semiotics should not be interpreted, or elaborated upon, within, or communicated from, the context of any single scientific discipline, but rather serves to interpret and elaborate upon all scientific disciplines.
Since semiosis is sign processing (i.e., sign interpretation and modelling), I find it difficult to conceive of semiosis as anything other than an awareness process. Endosemiotics employs the signal aspect of signs to explain physiology. I think this may be a metaphorical application (i.e., a category error, as previously noted). And biosemiotics seems to rely on the premise that living matter is different from non-living matter to explain biology and zoology. This also may be a category error.
So why would I use the term "semiosis" in my definitions of life? Because "semiosis" is a term that's understood (if not universally accepted) and used within the field of biology (which is best suited among the sciences to define "life"), and is general enough to include endosemiosis, psychosemiosis and cultural semiosis.
I can only confidently place the functions of interpretation and modelling within an awareness context (i.e., one where perception, cognition and intuition occur), and so hold that semiotics applies exclusively to mental (not physical) things.That said, I would be interested in any functional explanations which connect thinking with non-thinking, and living with non-living, domains (much as chemistry provides a functional connection between other natural sciences).