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Our future, our universe, and other weighty topics

Wednesday, March 6, 2019

The Tall Tale of Eukaryogenesis

The book Power, Sex, Suicide: Mitochondria and the Meaning of Life by biologist Nick Lane is one that advances a few unbelievable ideas. The most unbelievable idea it pitches is one concerning the origin of eukaryotic cells.

The cells in our bodies are very complex cells called eukaryotic cells. Such cells are vastly more sophisticated than the much simpler cells we see in bacteria. Such cells are called prokaryotic cells. The analogy that has sometimes been given is that a prokaryotic cell is like a studio apartment, and a eukaryotic cell is like a millionaire's mansion (although a better analogy might be to compare the eukaryotic cell to a skyscraper).  The difference between prokaryotic cells and eukaryotic cells is very poorly depicted by cell diagrams, which typically depict eukaryotic cells as being many times simpler than they are. 

How did eukaryotic cells originate? Our professors have now standardized on an answer, one that is extremely unbelievable. They now maintain that the first eukaryotic cell originated because of an incredibly improbable “combination” accident. The idea is that a bunch of prokaryotic cells somehow ganged up to become a eukaryotic cell – kind of like what would happen if five people collided into each other to somehow originate a new species of three-headed creatures which each had ten legs and ten arms.

Inside a eukaryotic cell are many specialized units called organelles. The organelles include things like ribosomes, lysosomes, mitochondria, and endoplasmic rheticulum. Our professors attempt to convince us that these mitochondria are ancestors of prokaryotic cells that somehow got incorporated into eukaryotic cells.

There are several reasons for thinking that such a thing is far too improbable to have ever happened. Among these are the following:

  1. No one has ever observed any type of event like the supposed event in which prokaryotic cells combined to become a eukaryotic cell. Microbiologists have done innumerable experiments with prokaryotic cells, and have never observed any combination of prokaryotic cells become anything like a eukaryotic cell.
  2. A prokaryotic cell injected with the DNA of a eukaryotic cell will not start producing eukaryotic cells as its offspring.
  3. Nick Lane evidently thinks that that the origin of eukaryotic cells through the process imagined by scientists is so improbable that it has occurred only once in the history of the universe. He states at the end of his book that he thinks “bacterial sludge is likely to be the climax of evolution across this lonely universe.” Similar statements have been made by other biologists, based on the vast improbability of prokaryotic cells combining to become a eukaryotic cell.  For example, biologist Michael Cobb has stated, "We could,  in  principle calculate the probability of the appearance of eukaryotes, but we would soon run out of zeros." 
  4. Nowhere in human DNA does it specify the overall shape of a human body, the structure of a human organ system, the structure of a particular human organ, the structure of a tissue, or even the structure of a cell. Although genotypes influence phenotypes, genotypes do not specify phenotypes. Genotypes merely list chemicals used by an organism.  DNA does not specify the physical structure of an organism. We can therefore imagine no conceivable event by which some lucky combination of prokaryotic DNA could result in a cell that produced eukaryotic offspring, because the structure of a eukaryotic cell is not even specified in DNA.
Let me explain why item 3 in this list is a very big reason for thinking that the “prokaryotic cells ganged up to become a eukaryotic cell” idea (sometimes called eukaryogenesis) is utterly unbelievable. Scientists estimate there are many trillions of other planets in the universe, and we have found many planets not very far from our planet. If a scientist has a plausible explanation for something, he or she will tend to maintain that such a thing will commonly occur elsewhere in the universe. For example, the collision of tectonic plates is a plausible explanation for earthquakes; and if you ask a scientist whether earthquakes occur on many planets, he will say that they do. But if you have an explanation for something that is extremely far-fetched and not at all plausible, you might tend to make a statement suggesting that such a thing happened only on our planet. When any scientist suggests that something has occurred only on our planet, it is a gigantic red flag suggesting that his explanation for that thing is not at all believable.

Show me a scientist who tells us that something happened because of a “once in the history of the universe” event, and I'll show you a scientist who does not have a remotely believable explanation for such a thing.

We may note that the modern account of eukaryogenesis (the origin of eukaryotic cells) is not at all a Darwinian account. The account relies on a sudden leap forward in nature rather than a gradual transition, breaking Darwin's rule that "nature does not make leaps." Just before evoking the principle of "nature does not make leaps," Darwin stated this on page 471 of the first edition of On the Origin of Species: "As natural selection acts solely by accumulating slight, successive, favourable variations, it can produce no great or sudden modification; it can act only by very short and slow steps." 

It is remarkable that while it is often claimed that Darwinism explains all the wonders of life, the modern biologist does not believe that Darwinian natural selection can explain either the origin of life itself (which must occur before natural selection begins) or the origin of eukaryotic cells.  To explain both of these origins,  our biologists must basically appeal to a special miracle of a type that has never been observed. In the lab chemicals have never turned into life, and prokaryotic cells have never turned into eukaryotic cells.  Hence neither abiogenesis (the claimed origin of life from non-living chemicals) nor eukaryogeneis (the claimed origin of eukaryotic cells from prokaryotic cells) fall into the category of observational science, and both exist in the same "cloud cuckoo land" realm of speculations as string theory and speculations about other universes.  For a theory of biological origins to fail to explain the origin of either the first life or the origin of the first eukaryotic cells is as embarrassing a shortfall as a theory of modern global conflicts that fails to explain either World War I or World War II. 

Let us look at some nonsensical statements Nick Lane makes on the last page of his book, in which he raves on and on about mitochondria with the same overzealous single-mindedness of a besotted teenybopper telling you that her new boy band crush is the secret to everything.

Lane: “Mitochondria teach us how molecules sprang to life on our planet, and why bacteria dominated for so long.”

Reality: This statement is not correct. Mitochondria are complex structures in a living cell, and did not exist before life existed. Mitochondria do nothing to explain the origin of life. 

Lane: “They [mitochondria] show us why bacterial sludge is likely to be the climax of evolution across this lonely universe.”

Reality: Taken literally, this statement is, of course, absurd, since humans (or something more advanced on another planet) must be regarded as the high point of the biological universe. Here Lane teaches that probably no other planet has eukaryotic cells (his "bacterial sludge" being mere prokaryotic cells). But teaching such a thing makes his theory of the origin of eukaryotic cells seem utterly unbelievable. If he had a plausible explanation for the origin of eukaryotic cells, he would not be suggesting that such an event was a unique miracle occurring only on our planet.

Lane: “They [mitochondria] teach us how the first genuinely complex cells came into being, and why, since then, life on Earth has ascended a ramp of complexity to the glories we see around us, the great chain of being.”

Reality: Here Lane portrays eukaryotic cells as “the first genuinely complex cells,” which is false. Prokaryotic cells simpler than eukaryotic cells are fantastically complex cells, requiring more than 100,000 base pairs arranged in a vastly improbable way to achieve functional performance. Mitochondria do not in any way teach us how eukaryotic cells came into existence, because the theory that eukaryotic cells originated from an incredibly unlikely combination of prokaryotic cells or mitochondria (probably an “only once in a universe” event according to Lane) is not at all a credible theory. And tiny fragments of cells such as mitochondria do not to any extent teach us how complex multi-cellular life could have originated, or why life would have or could have ascended a ramp of complexity leading to creatures such as us that are a trillion times more complicated than mitochondria. 

Lane: “They [mitochondria] show us why energy-burning, warm-blooded creatures arose, thrusting off the shackles of the environment; why we have sex, two sexes, children, why we must fall in love."

Reality: Mitochondria do nothing to explain the origin of warm-blooded creatures such as us, and to suggest otherwise is as silly as saying that bricks teach us why New York City arose. Mitochondria also do not explain the origin of sex, which is a gigantic difficulty for all naturalistic explanations of earthly life. You can understand only a small bit of the difficulty of explaining the origin of multi-cellular sex when you consider questions such as “which came first, the testicles or the vaginal canal,” two things that are useless (from a reproduction standpoint) without each other. There are a thousand such "which came first, the chicken or the egg" problems for anyone trying to explain biological innovations, making a mockery of claims that scientists understand such matters. 

The evidence given for the theory that eukaryotic cells arose from prokaryotic cells is laughably weak. The evidence given on one university page is that both mitochondria and prokaryotic cells have membranes, and that both have internal DNA. These are hardly strong reasons for thinking that mitochondria in eukaryotic cells are ancestors of prokaryotic cells. Using similar logic, I could argue that a dog must be an ancestor of me, because we have both four limbs and a head. The page neglects to tell us that the number of base pairs in the DNA of a prokaryotic cell is a hundred times greater than the number of base pairs in a mitochondrion, meaning that there is no strong similarity between the two.  A mitochondrion doesn't even look like a prokaryotic cell. 

You can read here a long Nautilus article about the modern-day folklore about the origin of eukaryotic cells.  Use some critical judgment, and you will find no solid evidence is presented. Calling the imagined origin event "ludicrously unlikely" despite arguing for it, the author says, "Prokaryotes have only managed it once in more than 3 billion years, despite coming into contact with each other all the time." But are not those 2.999999999999 billion years in which no such thing happened to prokaryotic cells evidence against the possibility of such a thing?

1 comment:

  1. So what is your explanation for the evolution of Eukaryotic cells?