| dbp:caption
| - The origin and evolutionary tree of life that is based on small-subunit RNA. The branches that perform oxygenic photosynthesis are labeled with 'O2'. The black arrow indicates the plastid endosymbiotic event that resulted in the origin of eukaryotic photosynthesis from cyanobacteria-like organisms, which ultimately became chloroplasts in algae and later in plants. However, while chloroplasts of the higher plants, glaucophytes, green and red algae are thought to be the result of the plastid endosymbiosis, all other groups of algae are assumed to have arisen due to the algal endosymbiosis , in which one eukaryotic alga was incorporated into another eukaryote. Only some branches of bacteria, eukarya, and archaea are displayed. (en)
- Parts of a chloroplast12px|right|link=|Diagram above contains clickable links|alt=Diagram above contains clickable links (en)
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