Has anyone noticed the role that “could have” now plays in Correct science?
Chemists studying how life started often focus on biopolymers like peptides and nucleic acids, but modern biopolymers don’t form easily without help from living organisms. A possible solution to this paradox is that life started using different components, and many non-biological chemicals were likely abundant in the environment. A new survey of a diverse set of such compounds under primitive environmental conditions found many of these easily formed polymers and some spontaneously formed cell-like structures …
Scientists have found many ways to make biological organic compounds without the intervention of biology, and these mechanisms help explain these compounds’ presence in samples like carbonaceous meteorites, which are relics of the early solar system, and which scientists don’t think ever hosted life. These primordial meteorite samples also contain many other types of molecules which could have formed complex folded polymers like proteins, which could have helped steer primitive chemistry. Proteins, by virtue of their folding and catalysis mediate much of the complex biochemical evolution observed in living systems. The ELSI team reasoned that alternative polymers could have helped this occur before the coding between DNA and protein evolved. “Perhaps we cannot reverse-engineer the origin of life; it may be more productive to try and build it from scratch, and not necessarily using modern biomolecules. There were large reservoirs of non-biological chemicals that existed on the primeval Earth. How they helped in the formation of life-as-we-know-it is what we are interested in,” says co-author Kuhan Chandru.
The ELSI team did something simple yet profound: they took a large set of structurally diverse small organic molecules which could plausibly be made by prebiotic processes and tried to see if they could form polymers when evaporated from dilute solution. To their surprise, they found many of the primitive compounds could, though they also found some of them decomposed rapidly. This simple criterion, whether a compound is able to be dried without decomposing, may have been one of the earliest evolutionary selection pressures for primordial molecules …
“We didn’t test every possible compound, but we tested a lot of possible compounds. The diversity of chemical behaviors we found was surprising, and suggests this kind of small-molecule to functional-aggregate behavior is a common feature of organic chemistry, which may make the origin of life a more common phenomenon than previously thought,” concludes co-author Niraja Bapat.
Tokyo Institute of Technology, “Scientists discover new organic compounds that could have helped form the first cells” at ScienceDaily
What does it mean to say “the origin of life a more common phenomenon than previously thought.” Can we point to other specific examples? It’s an interesting idea in principle but the wheels will probably come off fairly quickly.