The development of these metabolic pathways changed Earths atmosphere thereby altering the course of further evolution. 14 The evolution of eukaryotic cells most likely involved A endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria. Discovering The Link Between Nutrition And Skin Aging Disease Disorders Cardiovascular B anaerobic archaea taking up residence inside a larger bacterial host cell to escape toxic oxygenthe anaerobic bacterium evolved into chloroplasts. . C an endosymbiotic fungal cell. The evolution of eukaryotic cells most likely involved _____. Branch length is represented by the most likely number of point mutations that occurred during evolution of these species. 6 The evolution of eukaryotic cells most likely involved _____. They have produced particular mitochondria hydrogenosomes carrying out h 2 -producing fermentation for example in some ciliates 14 bu...