Endosymbiotic hypothesis
From Conservapedia
The Endosymbiotic hypothesis is a hypothesis used by evolutionists to explain the origin of certain eukaryotic organelles, specifically mitochondria and chloroplasts. Evolutionists believe that early in the course of terrestrial life, all cells were prokaryotes. It is hypothesized that at some point, endophagocytosis occurred whereby one bacteria "hijacked" the energy producing potential of another by engulfing a respiring or photosynthesizing bacteria.
Mitochondria and chloroplasts are the only organelles to contain their own DNA (other than the nucleus, which contains the DNA for the entire cell) and their DNA is well-conserved enough that they appear to be nearly separate organisms. DNA and RNA analyses have borne out much of this hypothesis; in particular, chloroplasts have a high amount of similarity with cyanobacteria (blue-green algae), and mitochondria strongly resemble proteobacteria. Some evolutionists argue that the nucleus is also the result of the endophagocytosis of an archaea. Further evidence supporting mitochondria and chloroplasts being endosymbionts lies in the fact that both organelles have plasma membrane bound spaces inside of their outer membranes, something no other organelle possesses. Many other eukaryotes have organelles which appear to have several layers of plasma membrane; evolutionists interpret this to mean that these are the result of a series of endosymbiosis events.
One problem with the endosymbiotic hypothesis is that endophagocytosis is not observed among existing prokaryotes.
Alternate hypotheses are that eukaryotic and prokaryotic cells were simply designed as they are. This, unlike the endosymbiotic hypothesis, is neither testable nor falsifiable, though it is consistent with other creation models which creationists claim are falsifiable.
