|Karo Michaelian |
'Thermodynamic Dissipation Theory
of the Origin and Evolution of Life',
12th printing, March 2017
There is such a person in Mexico. It is physicist Karo Michaelian. He called his theory Thermodynamic Dissipation Theory of the Origin and Evolution of Life. His view of life is a radical new theory about life and evolution based on the theory of dissipative systems. A dissipative system is a thermodynamically open system which is operating far from equilibrium in an environment with which it exchanges energy and matter. Examples of dissipative systems are hurricanes and living organisms. I am intrigued. I want to know more about it. Even if the theory only partially solved the origin of life, it would be a great contribution to science.
UV-resistant RNA and DNAMichaelian applies the theory of dissipative systems to the origin of life with interesting results. He points out that  both RNA and DNA are exceptionally strong absorbers and extremely rapid dissipaters of ultraviolet light UV-C (230–290 nm) . They do this within a picosecond, which is extremely fast (one millionth of one millionth of a second). There are no known other biotic or abiotic molecules that have this property, he claims. UV-C light from the sun could have penetrated the prebiotic atmosphere 4 to 2.5 billion years ago. The reason is that the ozone-layer (ozone shield) did not exist at the time , so UV-C light could not be absorbed by the ozone layer. This is before the origin of life. So, Michaelian suggests that DNA and RNA have those exceptional properties because they could resist the UV-C light of those days. In other words: DNA and RNA (especially the 5 bases) were thermodynamically selected. They were stable under those harsh conditions. If DNA and RNA have indeed those properties it makes sense that they were selected. Not only DNA and RNA: "There are also many other vestiges remaining in the fundamental molecules of life pointing to a UV-C environment at, or very near, the beginnings of life which would also have to be considered as mere accidents or coincidences..." (p. 307). This all makes sense and this is one of the potential valuable contributions to the Origin of Life field.
So, the explanation of why DNA has been 'chosen' as the hereditary molecule, is that it has been thermodynamically selected at a time 4 to 2.5 billion years ago. A relic of the past. This seems plausible because all molecules of those days must necessarily have been very resistant to UV light. You cannot call it natural selection, because we are talking here about non-living non-reproducing molecules. I guess other molecules were destroyed, but Michaelian does not tell us much about what happened for example with amino acids, peptides, proteins, lipids, sugars, etc. in those days.
Now we have short sequences of DNA or RNA. But that is not life. DNA should be replicated. Michaelian has ideas about that too ('Ultraviolet and Temperature Assisted Replication'). Still, this does not amount to life. But all other Origin of Life researches face the same problem. Michaelian is not the only scientist claiming a role for UV light. John D. Sutherland reports that his team created nucleic acid precursors starting with just hydrogen cyanide (HCN), hydrogen sulfide (H2S), and ultraviolet (UV) light . I don't know what the specific role of UV is in their scenario.
I am not an expert on these matters, so I have to rely on the opinion of Origin of Life researchers. I found a few isolated remarks which seem to support Michaelian. For example Koonin et al (2006): "... suggest that photosynthesis originated in the cyanobacterial lineage under the selective pressures of UV light and depletion of electron donors". That is similar to the main claim of Michaelian. There is a short supporting remark in Leslie Orgel (1973) . However, these are a few isolated remarks. Almost universally, when in the Origin of Life and evolution literature UV light or the ozone layer is mentioned, UV light is harmful. For example: "the damaging effects of solar UV, which was orders-of-magnitude stronger in the absence of the ozone shield than it is now" (source). And: "Skin cells that produced a pigment called melanin were advantaged because melanin is a natural sunscreen; it absorbs the energy of UV light and shields cells from the radiation’s harmful effects." ( source ).
Famous origin-of-life researcher Cairns-Smith wrote: "It is being realised too that ultraviolet sunlight is even better at destroying middle-sized organic molecules than at making them" . On the other hand, if UV creates ozone O3 from O2 that seems to be a creative process. Maybe that is a clue .
Returning to our remarks at the beginning of this blog. It still remains puzzling that UV light causes mutations, causes skin cancer  and is widely used as an sterilization method (anti-bacterial), is implicated in mass extinctions , and at the same time –according to Karo Michaelian– is instrumental in the production of the first molecules of life and at the same time according to mainstream science small amounts UVB radiation help synthesize vitamin D. How does this all fit together? Is it possible that proto-life was not damaged, but life today is damaged by UV? .
I would like to see experimental results with UV-C induced DNA and RNA synthesis published in a peer-reviewed scientific journal. Such an experiment would not be too complicated I guess. If successful that would be a major breakthrough in the origin of life field.
Poor PhotosynthesisNow the most remarkable claim of all. Applying his theory to photosynthesis: Karo Michaelian observes that photon dissipation into heat accounts for 99,9% of the free energy in sunlight and only 0,1% is used for photo-synthesis (p.70, p.312) . This is a crucial fact in his thinking:
"This represents an extremely poor efficiency for a photosynthetic system that has had the opportunity to evolve for at least 3,500 million years considering that humans have developed systems capable of converting up to 40% of the free energy in sunlight into usable electrical energy within only 40 years of technological innovation." (p.312)Michaelian concludes from these data that not photosynthesis, but photon dissipation into heat has the highest priority of plant species. It is not natural selection that rewards plant species with the highest photosynthetic efficiency, but it is the law of dissipative systems that selects plants with the highest dissipation , . Needless to say this is completely against the common sense and the Darwinian view of life .
His entire argument hinges on the assumption that it is possible to distinguish optimization of biomass production from optimization of the conversion of visible light into infrared light (heat). He claims thermodynamic dissipation is optimized and photosynthesis is not. However, if both processes are necessarily connected, then it is not possible to distinguish between the two, let alone to point to the one that is optimized! I think that they are two aspects of the same process. Two points of view that can not conflict and are both true.
Obviously, Michaelian would counter that the number 0,1% is decisive. It is just too small to be an optimum . But the number alone is cannot be decisive. We need to know whether is physically, chemically and biology possible at all to have a significantly higher efficiency. How can we know this? Comparing photosynthesis with solar panels is certainly no good. The purpose of solar panels is electricity production and nothing else. Plants do not produce electricity. In contrast with solar panels, photosynthesis means synthesis of carbon compounds (sugars) using CO2 + H2O + photons. Solar panels are not in the business of synthesizing carbon compounds. So, that comparison is wrong.
The conclusion that 0,1% is too low, is just as wrong as concluding from the fact that 98% of the human genome is non coding, that the function of the human genome is garbage collection. Or conclude from the high energy consumption of the brain that the purpose of the brain is heat production. Or conclude from the inefficiency of light bulbs and fossil fuel cars that the main purpose is heat production .
Despite 0,1% being a low number, it is enough for all life on earth. More than 7 billion people and even a larger number of cats, dogs, cattle and wild animals depend on photosynthesis.
A better idea would be comparing natural photosynthesis with artificial photosynthesis. The highest reported efficiency for artificial photosynthesis lab prototypes is 22.4%. However, plants are efficient in using CO2 at atmospheric concentrations, something that artificial catalysts still cannot perform (wikipedia). (Plants cannot control CO2 in the atmosphere!). So, until now natural photosynthesis still outperforms artificial photosynthesis.
Even if humans could significantly improve artificial photosynthesis, it would be comparable to improving milk production in cattle. It would not prove that milk production of wild cattle is inefficient. There are evolutionary and ecological reasons for this.
|Improving Photosynthetic Efficiency for Greater Yield|
Even if photosynthesis were the only factor in evolutionary fitness, it would not necessarily mean that the efficiency would be high. The reason is that there is enough sunlight. Literally more than enough. Whenever there is more than enough of a resource, there is no reason to have high efficiencies. "Crop leaves exposed to full sunlight absorb more light than they can use. If they can’t get rid of this extra energy, it will actually bleach the leaf. Chemical changes within the leaf allow the excess energy to be dissipated as heat, in a process called nonphotochemical quenching (NPQ)" (source). I think this is an important reason why the efficiency is 'low'. See also: Photo-inhibition, photoprotection.
Thermodynamic Limit. There is an intriguing reason why photosynthesis is not 100% efficient: thermodynamics! There is a Thermodynamic Limit: "At the reaction centers, thermodynamics limit the amount of energy available to do photosynthetic work."! (source), (source). I would like Karo Michaelian's comments! As a physicist he should be able to enlighten us.
Conclusion. The function of photosynthesis is carbon fixation: the most fundamental biological reaction which incorporates carbon atoms into organic molecules starting with carbon dioxide. Without carbon fixation no plants, no animals, no biosphere. We animals cannot live from the sun! We need photosynthesis because of the food it produces for us. We don't care if plants produce entropy when we are hungry. We cannot eat entropy.
However, his thermodynamic view is not wrong. All organisms are open thermodynamic systems that necessarily produce entropy: bacteria, plants and animals. Michaelian unnecessarily claims that Darwinian natural selection contradicts his 'thermodynamic selection', and natural selection should be replaced by 'thermodynamic selection'. More on that in the next blog. In this respect his views are over the top. He pushed it too far. That's a pity.
Michaelian cites another two experiments purportedly proving his theory. The first is 'A maximum hypothesis of transpiration in plants' (ref 392). This won't work in a hot, dry climate because plants would die if the tried to maximize evaporation. Second: 'Inactive Photosystem II Complexes in Leaves' (ref 47). However, the authors of the article conclude: "Although there are two few data to answer the question of whether inactive centers serve a useful role in photosynthesis, for example in photoinhibition, development, or otherwise, ..." (GK: 'two' must be 'too'). So, there is more research required to find out their functions.
|Genetically modified plants are better able to make|
use of the limited sunlight available when
their leaves go into the shade (source)
Others about Dissipative Systems and Life
"Go out and observe trees, and you will see living dissipative systems stretching skyward to capture available solar energy. ... This process is the result of the thermodynamic imperative to degrade the quality of the incoming solar energy as completely as possible." "Plants are perhaps the most advanced instrument yet evolved for degrading incoming solar radiation." (p.220).
- He points out that: See wikipedia article 'Abiogenesis'. The wording, the language, the style of the section 'Thermodynamic dissipation' are the same as in Karo Michaelian's book. So, probably Karo Michaelian wrote that section. It is a summary of the theory that only its author could have written. Or: it is a copy&paste work of somebody else.
- UV-C: Today UV light is used to kill bacteria! See: wikipedia article Ultraviolet germicidal irradiation. On the wikipage DNA there is nothing about DNA's exceptional resistance to UV-C. On the contrary: wikipedia tells us that UV-B damages DNA and causes mutations.
- Ozone layer appeared when oxygen levels were high enough (Great Oxygenation Event)
- Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism Nature Chemistry volume 7, pages 301-307 (2015)
- L.E. Orgel (1973) The Origins of Life, p. 117: "However, it has been shown that if hydrogen sulfide or formaldehyde were present in sufficient quantities in the atmosphere, they could have absorbed a much larger amount of ultraviolet energy and made it available for the synthesis of organic compounds." but also here: "ozone absorbs ultraviolet light strongly ... otherwise men would be subjected to very harmful doses of ultraviolet light."(p.117). There there seems to be universal agreement (1) there was no ozone layer at the origin of life, (2) UV light was hitting the earth surface, (3) UV is harmful. (added 2 May 2018)
- A. G. Cairns-Smith Seven clues to the origin of Life, 1985, p. 42.
- "No type of UV radiation has been shown to be safe – cancers have developed after exposure to UVA (alone), UVB (alone), and UVC (alone)." Source: Does UV radiation cause cancer? from the website www.cancer.org of the American Cancer Society. So, this is a serious source. Further, see the website of the Skin Cancer Foundation: UVC isn't a concern for skin cancer.
- See chapter 4: An ancient ozone catastrophe? in: David Beerling (2007) The Emerald Planet. (my review).
- p.70: KM quotes the lowest Photosynthetic efficiency. But it ranges from 0,1% – 1% to 2% (crops). Nonetheless: it seems to be low. KM emphasizes that everybody ignores this fact (p. 283). This is not true: "a surprising small amount of that energy is turned photosynthetically into biomass." (Eric Schneider, Dorion Sagan (2005) Into the Cool, p.221) however these authors don't draw very dramatic conclusions from this fact.
- "Instead, if plants and other photosynthetic organisms have evolved to optimize dissipation rather than photosynthesis ...". (page 234).
- Plants could not exist without carbon fixation. If carbon fixation is against universal law of dissipation-maximization then photosynthesis could not have originated in the first place.
- The 'purpose' of photosynthesis is the synthesis of carbon-compounds as glucose and ATP. Carbon-based life could not exist without photosynthesis.
- Photosynthetic efficiency is not a fixed number. For example the photosynthetic efficiency of oak forests drops from 1.5% - 1.7% at ages between 20 - 40 years to 0.4% at the age of 200 years (Schneider and Sagan, 2005, p.221).
- Growth pattern and photosynthetic activity of different bamboo species growing in the Botanical Garden of Rome.
- The tile of this blog 'The Origin of Species by Means of Thermodynamic Selection' is of course a paraphrase of Darwin's 'On the Origin of Species by Means of Natural Selection'.
- added May 2 2018: I couldn't believe when I first heard that the fuel efficiency of a fossil fuel car was only 25%! An invention some 100 years on the market!
- remark added May 2 2018
- If you believe in intelligent design: the extremely low efficiency of photosynthesis is an insult to the Creator. Creation is perfect. So, it must have happened right after the fall. Before the fall plants had a maximum efficiency only constrained by the laws of physics. (added 3 May 2018)
- In an email 17 May 2018 Karo Michaelian wrote: "in the book I do in fact "explain why in contrast to mainstream opinion UV is not harmful". I do that particularly in sections 4.2 (Of Pigments and Protectionism) and 19.13 (Pigments Provide Protection) and in many other places throughout the book." [added 17 May 2018]