As humans, one of the most challenging and provocative questions we can ask is how life on earth came to be. We know about evolution, survival of the fittest, the one fish brave enough to walk. But how did the first microorganism suddenly wriggle its way out the world of the inanimate and mark the beginning of life on earth? Researchers from Saint Louis University, the College of Charleston and the NSF/NASA Center for Chemical Evolution think they have a new clue regarding the Earth’s environment at the time, and it sounds a lot like barbeque and pool party weather!
One of the keys to the creation of life is proteins. Proteins are strings of amino acids held together by peptide bonds, and they are responsible for carrying out countless tasks in the cell from catalyzing reactions as enzymes to protecting against diseases as antibodies to controlling movement and muscle contractions. Previous research has found that subjecting amino acids to “repeated wet-dry cycles”creates an ideal environment for the formation of peptide bonds. The more peptide bonds, the more complex polymer proteins that form and carry out biological processes needed for sustaining life. According to our original article, “Were hot, humid summers the key to life’s origins,” scientists imagine that the pre-life climate on earth consisted of hot, sunny days broken by heavy rainstorms. However, when Luke Bryan said that “rain is a good thing,” I don’t think he was referring to the cultivation of peptide bonds, because too much rain can actually have an opposite effect on our pre-biological proteins.
Pictured above is two amino acids joining to form a dipeptide through dehydration synthesis (removing an H2O molecule to join two monomers)
While water is the basis for all biological function, too much water added to a solution can result in hydrolysis, the decomposition of polymers due to the insertion of water molecules between bonds. If the Earth’s early climate involved large rain storms, the rain would flood the amino acid mixture and prevent the formation of peptide bonds. So, what kind of climate would then be required to spark the creation of life? Angela M. Hessler, in her article “Earth’s Earliest Climate,” tells us that “evidence points to an unfrozen — perhaps balmy — Archean Earth” due to “100–1000 times more CO2 than present atmospheric level,” which gives the Earth a “greenhouse atmosphere.” This greenhouse climate consists of high temperatures and humid weather- basically summer weather! This humidity in the air allows the amino acids to receive the ideal amount of water for forming complex proteins. However, our researchers have also discovered another factor that aids the formation of proteins, the process’s own sort of catalyst that pairs perfectly with the humid climate of pre-biological Earth.
Deliquescent minerals are salts that absorb humidity out of the air and then dissolve. If deliquescent minerals are present while amino acids bond into polypeptides, they can regulate the wetness of the environment in which polypeptides form, creating a perfect environment for the creation of proteins! I guess we can take the Bible that much more literally when were were told, “For you were made from dust, and to dust you will return.”
Above is dipotassium phosphate, a highly deliquescent mineral that is likely to have been present during the first formation of polypeptides millions of years ago.
While to some it may seem inconsequential, this discovery is important! Think about it: whenever we talk about evolution, we talk about inheriting traits from our ancestors. But we never talk about our oldest ancestor. The ancestor that has no ancestors because they are the first thing to live on this Earth! This discovery gives concrete evidence for a plausible theory regarding the birth of life on this planet, that one cell that fathered everything that now sees and breaths and strives to reproduce. This article gives us the farthest glimpse possible into the past, and with this new information, we can start to learn more about how life rose from the ground to survive and thrive on Earth.
If you have any other ideas or remarks, please feel free to comment on this post! I would love to hear what you all have to say about this exciting, new discovery!
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