Chapter 1 - Studying Life - 1.1 - Living Organisms Share Similarities and a Common Origin - 1.1 Recap - Learning Outcomes - Page 12: 1

The emergence of photosynthesis drastically altered the history of life since it produced large macromolecules and oxygen, which in turn allowed more complex aerobic organisms to thrive. Aerobic organisms underwent aerobic metabolism, which was much more efficient at producing energy than anaerobic metabolism. Additionally the production of oxygen led to a thick ozone layer that protected organisms from harsh UV light that would otherwise kill them if they were not submerged in water.

The emergence of photosynthesis drastically altered the history of life since it produced large macromolecules and oxygen, which in turn allowed more complex aerobic organisms to thrive. Aerobic organisms underwent aerobic metabolism, which was much more efficient at producing energy than anaerobic metabolism. Additionally the production of oxygen led to a thick ozone layer that protected organisms from harsh UV light that would otherwise kill them if they were not submerged in water.