The Logic of Chance: The Nature and Origin of Biological Evolution

5. The web genomics of the prokaryotic world: Vertical and horizontal flows of genes, the mobilome, and the dynamic pangenomes

When Darwin wrote about evolution, he meant animals and plants—at least, he used these advanced multicellular organisms for all his concrete examples. Unicellular organisms hardly figure in The Origin of Species or any other work of Darwin. Nevertheless, given that Darwin seriously discussed the origin of all extant species from one or a few ancestral forms (see Chapters 2 and 11), he should have had an idea that these ancestors were unicellular.¹ Ernst Haeckel, the prolific German apostle of Darwin, placed Protista (unicellular eukaryotes often defined by the same term even now) and Monera (now known as prokaryotes—bacteria ...