"Describe the theory of endosymbiosis and the arguments for and against this theory"

Dr Lynn Margulis, a biologist from Boston University, proposed in the 1960's, the theory of endosymbiosis. It was then officially published in her book "Symbiosis in Cell Evolution". The theory suggests that cells originated as communities of interacting entities a could join together in a specific order. Organelles like mitochondria and chloroplasts were themselves prokaryotic cells before the development of eukaryotic cells. It was believed that a host cell, probably similar to amoeba, ingested a …

…does in fact exists in prokaryotic cells but in much smaller sizes. This suggests that prokaryotic cells does not necessarily evolved into eukaryotic cells. The arguments favouring the endosymbiotic theory have seemed too much of a coincidence and reasonable, so does the arguments arguing against the theory. It requires more research on earlier forms of prokaryotic and eukaryotic, and understanding, such as the functions of the independent DNA before a clear answer could be found.