Which consequence resulted from the increase of oxygen due to oxygenic photosynthesis?

The increase of oxygen due to oxygenic photosynthesis had significant consequences for Earth's biosphere. One major outcome was the cascading extinction of many prokaryotes, particularly anaerobic bacteria, which thrived in an oxygen-poor environment. As oxygen levels rose, these organisms experienced extreme stress or were unable to survive because they were adapted to an anaerobic (without oxygen) lifestyle. Oxygen is toxic to many anaerobes, leading to their decline and extinction in the face of rising oxygen levels, marking a drastic shift in the dynamics of life on Earth.

This shift also paved the way for the evolution of aerobic life forms that could utilize oxygen for cellular respiration, contributing to increased biodiversity. While the development of new forms of chlorophyll and the creation of terrestrial ecosystems were indeed influenced by oxygen levels, these events are more properly viewed as subsequent developments rather than direct consequences of the initial rise in oxygen levels. Enhanced growth of anaerobic bacteria does not align with the consequences of an oxygen-rich environment, as the result would be the opposite.