Chloroplasts and mitochondria are both thought to have evolved through the process of what
is called endosymbiosis.
Endosymbiosis is a process in which one organism lives inside another and develops a mutually beneficial relationship. In the case of chloroplasts and mitochondria, both organelles are believed to have originated from free-living bacteria that were engulfed by ancestral eukaryotic cells. Over time, these bacteria evolved to become specialized organelles that provided energy and other functions for the host cell.
Chloroplasts are specialized organelles found in photosynthetic organisms, such as plants and algae. They are responsible for converting sunlight into energy through the process of photosynthesis.
Mitochondria are organelles found in almost all eukaryotic cells that are responsible for producing energy through the process of cellular respiration. They are often described as the "powerhouses" of the cell.
Both chloroplasts and mitochondria have their own DNA and replicate independently of the host cell, providing evidence for their bacterial origins.