Did cells acquire organelles such as mitochondria by gobbling up other cells?
(Or, can the endosymbiont theory explain the origin of eukaryotic cells?)
6 July 2000
Eukaryotic cells, such as yeast and those of animals and plants, have a membrane-bound nucleus, chromosome structures and organelles such as mitochondria and chloroplasts, whereas prokaryotic cells, such as bacteria, lack these features. Many evolutionists believe Lynn Margulis’ idea that eukaryotic cells came about as a prokaryotic cell ‘ate’ (by a process called endocytosis) other prokaryotic cells, which then became the mitochondria and chloroplasts. The engulfed cells supposedly reproduced in step with the host cell in some sort of symbiosis (mutual advantage), just by chance, before coming under the control of the primitive eukaryotic cell (which developed chromosome structures, nuclear membrane, Golgi apparatus, etc, etc, also). Over time, portions of the mitochondrial and chloroplast genomes happened to transfer to the nucleus.
Problems abound with this scenario. For example, how could the enveloped cells reproduce in close synchronicity? How did lateral gene transfer into the nucleus take place when the nuclear membrane is designed for the passage of mRNA (out), and to contain DNA? If DNA were passed between the engulfed cell and the host cell, would not the host respond by degrading the foreign DNA, because it would detect it as a virus? (Note that the enzymes used so widely to chop up DNA into pieces in DNA sequencing studies come from bacteria, i.e. prokaryotes—they function in destroying foreign DNA inside the bacteria.)
It is only to be expected that there would be similarities in many of the genes for photosynthesis or respiration between prokaryotes and eukaryotes—they have to achieve the same chemistry (photosynthesis: light energy + carbon dioxide + water giving glucose plus oxygen. Respiration: glucose (C6H1206) giving CO2 + H20 + energy). Furthermore, they have the same Designer! For an in depth treatment of the concept that God designed things in a way to reveal himself and thwart naturalistic explanations of origins, see The Biotic Message (right).
However, detailed studies of the DNA base sequences have shown that the pattern of similarity between eukaryote and prokaryote is not what would be expected from the endosymbiont hypothesis. Doolittle said,
‘Many eukaryotic genes turn out to be unlike those of any known archaea or bacteria; they seem to have come from nowhere.’ (Doolittle, D.F., Uprooting the tree of life, Scientific American 282(2):72–77, 2000.).
The endosymbiont idea was severely dealt with in the 70s and early 80s, and should have died. But, what else is there for the evolutionist? It is very much akin to chemical evolution—anyone who knows a little of the biochemistry involved in the most basic of bacteria knows that formation of a living cell from chance chemical reactions, even in highly controlled/contrived Miller-type experiments, is absolutely impossible. But that it happened is deemed to be certain (well, we have living cells, don’t we?!) and it is taught that way in universities around the world. For a thorough refutation of the idea that life could form by natural processes, see the Origin of life articles.
However, something like this must have happened, because we have plants, for example, which are fantastically complex things and they must have arisen from some stepwise evolutionary process (Did I just hear someone say they think the cells were created? Now listen here, that’s religion, which has nothing to do with the real world of cells and science. Science is about material explanations, and just you remember that! We just will not accept an intelligent cause, regardless of whether the evidence supports it!). See Lewontin’s admission regarding the materialistic bias applied in much scientific reasoning today about origins.
Note that this view that science can only deal with materialistic answers is a modern misuse of science. The founders of modern science did not see things that way (Newton, Kepler, Boyle, Faraday, Pasteur, Kelvin, Pascal, etc.)—see Creation scientists. There are many modern highly qualified scientists who believe Genesis literally—see In Six Days: Why 50 [Ph.D.] Scientists Choose to Believe in Creation. Read online.
And science does deal with non-observable, intelligent causes where it suits the practitioners—for example, forensic science is all about finding evidence that ‘person X poisoned person Y with strychnine’, for example (natural causes cannot account for person Y’s body containing strychnine, so someone, an intelligent agent, was responsible). Likewise, the SETI program is tacit agreement that science can tell the difference between natural causes and intelligent causes (certain patterns on radio signals from outer space could not be explained as originating from natural forces). Also, archaeology is much about recognising that an axe-head, for example, was created by an (unseen) intelligent agent, because the structure of an axe-head is so unlikely to arise from natural chemical and physical processes. See the article A brief history of design.
It is the atheistic bias of modern practitioners of science that prevents them from seeing the abundant evidence, right under their noses, for the unseen Creator of life. There is more evidence than there ever has been for there being a Creator. Unbelieving scientists are in willfully ignorant denial (Rom. 1:20 ff., 2 Peter 3).