Endosymbiosis

The theory of endosymbiosis is that eukaryotes may have developed some of their internal cell structures/organelles from one cell engulfing another cell and then both developing a type of symbiotic relationship. Each engulfed cell would eventually serve a specialized function in support of the new single eukaryotic cell and eventually neither portion would be able to exist independently.

This theory was originally developed by Lynn Margulis and there have been various discoveries that have supported it. One of the organelles thought to have been incorporated in this fashion is the mitochondria. Aspects of mitochondria that support this theory in that they have their own circular DNA, like prokaryotes, and their own ribosomes. When additional