The proposed endosymbiotic scenario of eukaryogenesis and subsequent origin of phagocytosis. The evolutionary tree of archaea is shown as a multifurcation of 5 major branches: Crenarchaeota, Euryarchaeota, Korarchaeota, Thaumarchaeota, and the hypothetical Archaeal Ancestor of Eukaryotes which is depicted as an irregular shape to emphasize the likely absence of a rigid cell wall. LECA, Last Universal Eukaryotic Ancestor. HGT, Horizontal Gene Transfer. The primary radiation of eukaryotes is shown as a multifurcation of 5 supergroups: Unikonts, Chromalveolata, Excavates, Rhizaria, and Planta. At least, three of the supergroups evolved full-fledged phagocytosis (Ph).