It is believed that mitochondria were acquired by primitive eukaryotic cells before chloroplasts were. What is the evidence for this?

Virtually all eukaryotic cells contain mitochondria, whereas only certain groups of eukaryotic cells have chloroplasts. It is therefore assumed that mitochondria were acquired before the eukaryotes diverged into the separate lineages that gave rise to animals, plants, fungi, and the single-celled protists. Later, after this diversification had begun, photosynthetic bacteria were acquired only by the branch that gave rise to photosynthetic eukaryotes.