Consciousness and sentience are not exclusive to animals with nervous systems but are grounded in the fundamental biology of all cells. The cellular basis of consciousness (CBC) model proposes that the excitable plasma membrane, which defines a cell's internal and external domains, is the foundation for biological awareness. This article examines the biomolecular structures and processes that enable and sustain this cellular consciousness from an evolutionary perspective, arguing that unicellular organisms like protists and algae, as well as the cells of multicellular fungi, plants, and animals, all possess a primitive form of sentience rooted in general cell biology.
Plants are increasingly understood as complex agents rather than passive organisms. This theoretical synthesis integrates Cellular Cognitive Biology, Biosemiotics, and Phenomenology to describe how plant agency arises from autopoietic organization and enactive sense-making. At the cellular level, the senome—a multimodal analog interface—and the electrome allow real-time environmental evaluation. Bioelectric and mechanical perturbations cross a semiotic threshold, becoming meaningful signs through semantic couplings. Plant agency scales from individual cells to the whole organism as a decentralized modular system, projecting sentience into surroundings via extended cognition, driving niche construction and a plant semiosphere. The N-space episenome enables holobiont emergence, linking individual senomes into a distributed hypersenome for shared decision-making and collective survival. This shared agency demands a reconciliation between ontology and ethics, grounding a new environmental ethics and legal recognition of nature.