Question

multiple - choice 2.5 points
what had to become prevalent before aerobic respirating bacteria could grow in number in the ancient seas (prior to the development of endosymbiosis/eukaryotes)?
oxygenic photosynthesis
organic photosynthesis
methanogenesis
fermentation
any photosynthesis

Explanation:

Oxygenic photosynthesis is crucial as it produces oxygen. Before the evolution of oxygen - producing (oxygenic) photosynthetic bacteria, the atmosphere had little free - oxygen. Anaerobic organisms dominated. Oxygenic photosynthesis changed the redox state of the environment and made it possible for more complex life forms to evolve and for bacteria to grow in new ecological niches. Anaerobic respiration and fermentation are energy - generating processes that do not require oxygen, but oxygenic photosynthesis was key in changing the environmental conditions to allow for more diverse bacterial growth in the ancient seas.

Answer:

Oxygenic Photosynthesis