: cyanobacteria : Cyanobacteria fossils from 1.75 billion years ago show the first known example of photosynthesis in their thylakoids.  Photosynthesis is responsible for all metabolism of life in earth today, including everything we eat.

above | Figure 7. Schematic representation of Synechocystis cell morphology. (A) cross-sectional view of Synechocystis cell with pili. (B) ultrastructure of Synechocystis cell — from Cyanobacteria: Model Organisms and Beyond