Cyanobacteria, stromatolites, oxygenation and banded iron formations across Earth’s spheres

What this note covers

1. Cyanobacteria and stromatolites: the evidence for early photosynthetic life
2. Effect on the atmosphere: the Great Oxidation Event
3. Effect on the hydrosphere and geosphere: banded iron formations
4. Building the cause-and-effect chain
5. Reading stimulus material on Precambrian change
6. Exam technique and model sentences

6 sections · 10 key terms & formulas · 6 common mistakes