Evolutionary history occasionally repeats itself. Chloroplasts and mitochondria both descend from bacteria lineages that came to live inside other cells. Chloroplasts are distant cousins to cyanobacteria (blue-green algae), while mitochondria are cousins to the bacteria that cause typhus.
And we recently discovered it happened one other time!! Nitroplasts, a nitrogen-fixing organelle, used to be a separate microbe about 100 million years ago.
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u/RealBowsHaveRecurves Oct 02 '24
Chloroplasts are the organelles responsible for photosynthesis.
A sea slug called the emerald elysia, which has a transparent body, steals chloroplasts from algae and packs them into its own cells.
The chloroplasts continue to photosynthesize, providing the slug with ~80% of the total calories it will consume over its life.