DAVID: I didn't think it needed comment as I interpret that he is referring to the complexity of the single cell which arrived at about that time. > > dhw: So do you think the complexity of the first single cells constitutes “all of life's most important innovations”? I thought you thought the purpose of evolution was to produce humans. -My comment is quite clear. That first momentous invention of a stand-alone single cell is all he was inferring to. Multicellularity then built on it with conglomerations of automatic organs running without my help so I can live my life unrestrained by having to make decisions about my urine concentration.