Explore how organisms obtain carbon and how photosynthetic prokaryotes changed Earth’s early atmosphere in IB Biology SL B4.2.3.
There is evidence that prokaryotes were responsible for changes in the atmospheric gases 3.5 billion years ago. Outline the role of bacteria in producing an oxygen-rich atmosphere.
early prokaryotes were anaerobic/did not require oxygen
population increased / shortage of food
photosynthetic bacteria/cyanobacteria evolved
produced/released oxygen (into the atmosphere)
by splitting water molecules/photolysis/photosynthesis
concentration of oxygen built up over time / conditions changed from reducing to oxidizing