Lifeless matter could only have evolved into self-replicating molecules by growing more complex. Discover how destruction might make this counterintuitive process conceivable.
Lemon, the yellow beagle I had as a small boy, wasn’t feeling well. It turned out that he had worms. I asked my dad how dogs get worms.
Dad explained that worms come from insects. Fleas and mosquitoes spread the eggs from one dog to another. So then I asked where the bugs got the eggs. Dad told me that they got them from other dogs.
Then I pointed out that none of that explains how dogs started getting worms in the first place. In frustration, my dad responded, “Well, I don’t know where the first worm came from!”
CAN’T FULLY EXPLAIN HOW LIFE ORIGINATED
Nobody else knows either. Even today, despite the tremendous progress made in evolutionary biology over the last two decades, scientists still can’t fully explain how life originated from lifeless matter.
Strictly speaking, the origin of life and evolution are two different things. Evolution explains how species emerge through descent with variation and natural selection. That implies that an earlier form of life existed from which the new species could descend.
None of that explains how life arose from lifeless matter. The word for that field of study is abiogenesis. Abiogenesis must have resulted from some form of chemical evolution that predates living things.
REPLICATING CHEMICALS BECOME LESS COMPLEX OVER TIME
One obstacle to understanding how this could have happened came to light through molecular biologist Sol Spiegelman’s work. He showed that replicating chemicals become less complex over time rather than more complex.
Smaller, simpler chemicals are more likely to evolve than larger, more complex ones. Spiegelman showed that there was a kind of entropy at work in chemical evolution.
This principle would have worked against more complex chemical compounds arising from simpler ones. Since this was a paradox that frustrated his colleagues, his discovery is known as “Spiegelman’s monster.”
DISCOVERY IS KNOWN AS SPIEGELMAN’S MONSTER
Last week, the German Chemical Society’s journal Angewandte Chemie published a study that addressed this troublesome monster. Team member Professor Sijbren Otto of the University of Groningen summarized the paradox this way.
“Complexity is a disadvantage during replication, so how did the complexity of life evolve?” In an earlier experiment, Professor Otto developed a self-replicating system where chemicals replicate themselves, producing fibres from simpler compounds.
In this study, he and his colleagues set out to find a way to outwit Spiegelman’s monster and allow more complex fibres to arise from simpler ones. They believed that introducing destruction into the system would enable complexity to emerge and flourish.
INTRODUCING DESTRUCTION INTO THE SYSTEM
Professor Otto’s fibres consist of a series of self-assembling, stacked rings. These rings were all the same size, but the team adjusted the experiment to create two ring sizes.
In the past, the chemical evolution of stacks of small rings consistently outperformed stacks of large rings. In the new experiment, the researchers introduced a compound that broke up the rings inside the fibres.
With this new constraint, the larger rings survived, while the smaller rings were destroyed. Although the smaller rings could still replicate faster, the larger, more complicated rings became dominant.
DISCIPLINE TO REPRESENT NATURAL SELECTION
It seems as though it’s not enough to artificially simulate descent with variation. We also need to introduce some sort of discipline to represent natural selection.
In many species, the vast majority of organisms don’t survive long enough to pass on their genes. This harsh standard enables functional and more complex mutations to take hold and multiply.
The Hindu Trinity has three deities – Brahma, Vishnu and Shiva. Brahma creates, Vishnu sustains, and Shiva destroys. India’s ancient peoples told each other stories that explained the universal principles of birth, life, and death.
DESTRUCTION MADE WAY FOR RECREATION TO ARISE
They were also wise enough to explain that Shiva’s destruction wasn’t pointless or chaotic. Destruction made way for recreation to arise. The archetype of the phoenix is a similar idea.
This new discovery suggests that this is at least one way in which lifeless matter could become more complex instead of following the Law of Entropy and losing its structure. Perhaps, in a world that includes destruction, only the adaptable thrive and elaborate, even among inanimate chemicals.
That may be true of death among living things as well. Does the end of one generation make way for new life to come into its own and progress? As tragic as death feels to us, death and birth, destruction and creation, might be two sides of the same coin.
EXTINCTION OF THE DINOSAURS MADE ROOM FOR MAMMALS
The extinction of the dinosaurs made room for mammals to take over Earth’s continents. Humanity might never have arisen if a destructive asteroid hadn’t wiped out the colossal reptiles. Destruction may turn out to be one of those natural laws by which our Universe organizes itself.
At the very least, the study shows that lifeless matter can get more complex without violating nature’s laws. Spiegelman’s monster isn’t invincible.
“All in all, we have now shown that it is possible to beat Spiegelman’s monster,” Professor Otto explained. “We did this in a particular way, by introducing chemical destruction, but there may be other routes. For us, the next step is to find out how much complexity we can create in this manner.”
DESTRUCTION MIGHT BE ONE OF MANY FACTORS
Destruction might be just one of many factors that led to life self-organizing in a chemical soup. Charles Darwin famously imagined it like this.
“But if (and oh what a big if) we could conceive in some warm little pond with all sorts of ammonia and phosphoric salts, light, heat, electricity etcetera present, that a protein compound was chemically formed, ready to undergo still more complex changes.”
STILL “A BIG IF”
This study points us toward understanding how that compound might have formed. However, it’s still “a big if,” and our story remains full of gaps.
Professor Otto summed up the team’s results by saying, “This means that we can now see a way forward. But the journey to producing artificial life through chemical evolution is still a long one.”
We always have more to learn if we dare to know.
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