A critical analysis of the Theory of Endosymbiosis and it’s supporting evidence Abstract Introduction The endosymbiotic theory is an evolutionary theory explaining the origin of Eukaryotic cells from Prokaryotic, and is at present; the most widely accepted evolutionary theory of the Eukaryotic cell. The theory explains the origins of mitochondria and chloroplasts and their double membranes, suggesting that chloroplasts and mitochondria represent formerly free-living bacteria that were taken into
The first endosymbiotic event involved the engulfing of an alpha proteo bacterium by a proto-eukaryote, giving rise to the presence of mitochondria in cells. Chloroplasts developed from cyanobacteria. After this first endosymbiotic event which led to the evolution of cells to incorporate mitochondria, there was an endosymbiotic event which led to the engulfing of cyanobacteria by eukaryotic cells . Fig.
ancestor. This essay will focus on: the early evolution of our eukaryote ancestor during Precambrian period, plastids origin along the algae family due to second endosymbiosis; discuss the evidence that supports the theory, including further examples of endosymbiosis. The theory, as discussed by Lynn Margulis, states that mitochondria originated from α-proteobacteria bacterium which was engulfed by the ancestral anaerobic eukaryotic cell, through endocytosis, and retained within the cytoplasm