Sunday, December 11, 2016

the semiosis of evolution

springer |  Most contemporary evolutionary biologists consider perception, cognition, and communication just like any other adaptation to the environmental selection pressures. A biosemiotic approach adds an unexpected turn to this Neo-Darwinian logic and focuses not so much on the evolution of semiosis as it does on the semiosis of evolution. What is meant here, is that evolutionary forces are themselves semiotically constrained and contextualized. The effect of environmental conditions is always mediated by the responses of organisms, who select their developmental pathways and actions based on heritable or memorized past experience and a variety of external and internal signals. In particular, recognition and categorization of objects, learning, and communication (both intraspecific and interspecific) can change the evolutionary fate of lineages. Semiotic selection, an effect of choice upon other species (Maran and Kleisner 2010), active habitat preference (Lindholm 2015), making use of and reinterpreting earlier semiotic structures – known as semiotic co-option (Kleisner 2015), and semiotic scaffolding (Hoffmeyer 2015; Kull 2015), are some further means by which semiosis makes evolution happen.

Semiotic processes are easily recognized in animals that communicate and learn, but it is difficult to find directly analogous processes in organisms without nerves and brains. Molecular biologists are used to talk about information transfer via cell-to-cell communication, DNA replication, RNA or protein synthesis, and signal transduction cascades within cells. However, these informational processes are difficult to compare with perception-related sign processes in animals because information requires interpretation by some agency, and it is not clear where the agency in cells is. In bacterial cells, all molecular processes appear deterministic, with every signal, such as the presence of a nutrient or toxin, launching a pre-defined cascade of responses targeted at confronting new conditions. These processes lack an element of learning during the bacterial life span, and thus cannot be compared directly with complex animal and human semiosis, where individual learning plays a decisive role.

The determinism of the molecular clockwork was summarized in the dogma that genes determine the phenotype and not the other way around. As a result, the Modern Synthesis (MS) theory presented evolution as a mechanical process that starts with blind random variation of the genome, and ends with automatic selection of the fittest phenotypes. Although this theory may explain quantitative changes in already existing features, it certainly cannot describe the emergence of new organs or signaling pathways. The main deficiency of such explanations is that the exact correspondence between genotypes and phenotypes is postulated a priori. In other words, MS was built like Euclidean geometry, where questioning the foundational axioms will make the whole system fall, like a house of cards.

The discipline of biosemiotics has generated a new platform for explaining biological evolution. It considers that evolution is semiosis, a process of continuous interpretation and re-interpretation of hereditary signs alongside other signs that originate in the environment or the body.