What if… Sponges Originated 890 Million Years Ago? On the Emergence of Some Precursors of Animal Sentience

The recently described 890-million-year-old sponge fossil illuminates the early evolutionary path to the emergence of animal sentience. A sentient animal is aware of feelings and sensations due to the activity of a nervous system. Indirect markers suggest that the foundations of sentience originated hundreds of millions of years before the Cambrian. If the first neuron was a sensory cell, the presence of epithelial “neural stem cells” in ancient Porifera may have been the ancestral state of the nerve cell that appeared in Eumetazoa. In addition, sponges have neurotransmitters, such as Glutamate and GABA, and other molecular markers, such as EflMsiA, Piezo ion channel and Notch. If the 890-million-year-old fossil is identified as a sponge, the emergence of the buiding blocks of sentience among animals began much earlier than previously thought.