As the title suggests an explanation is given for the origin of life and the endosymbiotic theory. Oparin’s (1924) hypothesis alluded to the spontaneous generation of life via chemical and physical processes. In 1953 Miller and Urey performed an experiment to support Oparin’s hypothesis; they formulated organic compounds from water vapour and other gases. In fact , amino acids were formed as a result of natural forces acting on inorganic molecules in the experiment. In the 1960s Lynn Margulis formulated the endosymbiotic theory which postulates that eukaryotic cells arose from symbiotic relationships between prokaryotic cells.