Explore photosynthesis as a nutrition mode through cyanobacteria’s historical role and oxygen release by algae in IB Biology HL 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.
a. early prokaryotes were anaerobic/did not require oxygen;
b. population increased / shortage of food;
c. photosynthetic bacteria/cyanobacteria evolved;
d. produced/released oxygen (into the atmosphere);
e. by splitting water molecules/photolysis/photosynthesis;
f. concentration of oxygen built up over time / conditions changed from reducing to oxidizing;