Countless ideas and theories exist about the origin of life, but they have not yet led to a conclusive, evidence-based explanation. As a result, all kinds of secondary questions remain unanswered. Like asking a reader who writes: “Was the origin of life a one-time event or does new life still appear spontaneously?”
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A good question in a timely manner, answers Dr. Alex Blokhis, a postdoctoral researcher in the oLife (Origins and Evolution of Life) program at the University of Groningen. “The correct and honest answer is, of course, that we don’t know yet, but if you had asked this question ten years ago, it would probably have been the unanimous answer of scientists that it worked once and that life no longer exists spontaneously.”
There is now a more accurate view on the matter. Not because we now suddenly know what is going on, says Blochis, but because we are increasingly aware that the scientific knowledge we have accumulated is not enough to reach such a firm conclusion. In other words, we no longer have a good excuse to say that life has not yet appeared. We’re more actively questioning all kinds of common assumptions and I see that as progress.”
But where do these bold claims come from? According to Blokhuis, many assumptions have been made over the years which were initially recognized as hypotheses, but have been repeated so often and at times actively promoted by Big Names in science that they have gradually evolved into ‘facts’. “During my PhD research, I reviewed a lot of old articles to see what scientists claimed, researched and concluded about the origin of life, and then it turns out that there are a lot of assumptions that are unfounded. There is no evidence for that at all. You can learn a lot. Once you refer to the scientific literature.”
Sulfur mud pool at Solfatara, an active volcano near Naples. Did the first life arise in such a warm pond filled with “primordial soup”?
One of those common assumptions is that uncontrolled chemical reactions always lead to chaos. If you give up on chemistry you end up with “caramel”; An inoperable and disorganized block where nothing is possible anymore. Certainly not like a life that is well organized. Blochis: “This is an argument you often hear. But the honest answer is that we don’t really know what exactly happens in such a complex mixture. It is very likely that phase separation will occur, for example because some substances together form a drop or a bubble. Then you get conditions very different locally and provides organization and structure.”
Another old argument that often appears is the purported paucity of autocatalysis—the phenomenon that enables and speeds up molecules to form. This is also an important next step towards selecting certain molecules, because those who can make more of themselves, outcompete others that cannot, and thus have a better chance of continuing to exist.
“However, the prevailing view is that self-stimulation is a very special thing, rarely occurring in nature,” Blochis says. Therefore, the chance of life continuing to arise spontaneously is nil. “But in order to see and recognize something, you have to be open to it. We now know from other areas of chemical research that are not concerned with the origin of life but with catalysis that autocatalysis is not at all rare.”
Information carriers of life: RNA and DNA. According to proponents of the “RNA world” theory, it all started with RNA. But hard evidence is lacking, and the theory has many opponents.
Chemistry always gets messy. Self-stimulation is necessary but rare. Then there are also practical arguments that are often put forward, such as “If life appears again, it will be immediately devoured by existing life, so we will never find it again”. According to Blokhuis, these are all easy stories to get rid of the hassle.
But how does he think we’ll come up with better answers? “Indeed, all of us, that is, everyone working on the origin of life, must again take an inventory of everything that has been invented, researched, and published and look at it with an open mind. What are the solid conclusions, what evidence is there, and what assumptions are absolutely groundless , etc. Until we have better control over what we do and don’t know and can decide how we can expand our knowledge. If you really want to move forward, just rely on the things you can prove.”
In addition, other scientific research of course did not stop. Many new techniques and methods have been developed in chemistry and physics that can also help in research on the origin of life. “We can now research, compute, and predict more when it comes to complex systems.” Then there is the arrival of a relatively large group of young researchers interested in the field. Blokhuis: “Breathing fresh air is good, and there will be more room for new insights and a skeptical approach to the prevailing views. There is more room for criticism and that is a profit.”
An ocean floor thermal vent in the Mariana Trench. Did first life arise from such a source? Lots of empirical research is being done on this, but there’s no real evidence here either.