Final answer:
The increase in atmospheric oxygen from photosynthesis led to significant evolutionary developments including aerobic respiration, the extinction of many anaerobic organisms, the evolution of complex life forms and efficient respiratory systems, and the creation of new metabolic processes.
Step-by-step explanation:
The increase in oxygen produced by the first photosynthetic organisms, such as cyanobacteria, had profound effects on evolution. As photosynthesis evolved, oxygen began to accumulate, leading to the oxygen catastrophe for anaerobic organisms which could not survive in oxygen-rich environments. This event caused a dramatic change in Earth's biosphere and allowed for the following:
- It led to the development of aerobic respiration in organisms which is a more efficient form of energy production.
- The presence of oxygen allowed for the evolution of more complex and energy-demanding organisms.
- It triggered the extinction of many anaerobic organisms that could not tolerate the high levels of oxygen.
- It facilitated the evolution of larger and more efficient respiratory systems that could make use of the abundant oxygen.
- It promoted the evolution of new metabolic pathways and biochemical processes to handle and exploit the abundance of oxygen.
Additionally, the resulting ozone layer from the oxygenation of the atmosphere provided protection against harmful UV radiation, allowing for increased colonization of the land.