Fig. 1.

Effects of anesthetics in different taxa of organisms. Conserved effects are in the bottom rows (molecular-cellular) and grade to more taxon-specific effects in the middle and top rows. Note that the effects on mitochondrial complex I have only been shown for animals/humans but may well be present in plants and single-celled organisms (see main text). Sources of the illustrations are (1) http://www.biology-resources.com/drawing-paramecium.html (D.G. Mackean); (2) https:www.biologie-seite.de/Biologie/Venusfliegenfalle (William Curtis 1790); (3) Frieda Kahlo painting, 1944 (the broken column showing the results of her spinal surgery for a painful back injury); (4) a fearful cat. Charles Darwin (1872) The expression of emotion in man and animals. John Murray, London