is important because it is a theory that explains the origin of chloroplast and mitochondria. It is also a theory that explains how eukaryotic cells came to be.

The evolutionary theory that explains the origin of eukaryotic cells from prokaryotes. A long time ago, a photosynthetic prokaryote was ingested by a larger one but it was not digested. It somehow survived and it was trapped in the cytoplasm. This is called endosymbiosis, endo = inside, sym = together, bio = life, life living together inside.

5 Evidence: 1) Chloroplast / Mitochondria have their own separate circular DNA similar to 2) Both Chloroplast / Mitochondria have their own 2 membranes. The inner membrane came from the original cell, the outer came from the host 3) Mitochondria are about the same size as bacteria 4) Mitochondria came from purple bacteria and chloroplast came from the photosynthetic bacteria 5) Mitochondria and chloroplast reproduce from