A theory of the origin of eukaryotic cells (“higher” cells which divide by classical mitosis) is
presented. By hypothesis, three fundamental organelles the mitochondria, the
photosynthetic plastids and the (9+ 2) basal bodies of flagella were themselves once free-
living (prokaryotic) cells. The evolution of photosynthesis under the anaerobic conditions of
the early atmosphere to form anaerobic bacteria, photosynthetic bacteria and eventually
blue-green algae (and protoplastids) is described. The subsequent evolution of aerobic …