The defining principle of evolutionary biology is that all species, extant and extinct, evolved from ancient prokaryotic cells. Their initial appearance and adaptive evolution are proposed to have been accompanied by a cellular sentience, by feelings, subjectivity or, in a word, 'consciousness'. Prokaryotic cells, such as archaea and bacteria, have natural unitary, valence-marked 'mental' representations. They process and evaluate sensory information in a context-dependent manner. They learn, establish memories, and communicate using biophysical fields acting on excitable membranes. Symbiotic eukaryotic cells, (...) which evolved much later, initiated a compound cellular subjectivity utilizing 'senomic' and 'ephaptic' principles that evolved into the varieties of consciousness seen in multicellular species. This Cellular Basis of Consciousness (CBC) model provides a novel framework within which to approach fundamental issues such as the origins of life and the emergence of mind. (shrink)