Last time, I promised that I would say something about the evolution of molecules as Step 1 in the origin of life. The creationist organization Answers in Genesis says it’s impossible for molecules to evolve, much less to evolve into life:
Natural selection cannot be the mechanism that caused life to form from matter as it can only work on a complete living organism.
Is that true? Can natural selection only operate on complete living organisms?
This post is part of a series on creationist arguments that I encountered while studying the creation/evolution issue. I wanted to learn the truth, and creationists did not help their cause as they asserted so many obvious falsehoods. Answers in Genesis’ statement above is a case in point.
Think about it from the perspective of common sense. Wherever you have reproduction with variation, you will have natural selection: the variants that reproduce better than other variants will tend to predominate. How could it be otherwise? It’s almost tautological.
“Complete living organisms” aren’t the only things that reproduce. Molecules can reproduce, too, and researchers are closing in on what the first self-replicating molecules might have been.
RNA, the likely precursor of DNA, probably figured into the mix. The flu virus with which we’re all familiar has an RNA genome. Although viruses are in a grey area between life and non-life (not a “complete living organism”), the flu undergoes mutation and natural selection at such a rate that new vaccines must be developed every year.
The flu needs a living cell in which to reproduce, but in 2002, an RNA molecule was discovered that could replicate itself with no living thing in sight. Within a decade, experimenters had evolved it to the point where it could double in population every 5 minutes. That’s a 10100 increase every 36 hours. (See the end of this article, which contains a wealth of other information and is well worth reading.)
A bare RNA molecule is surely not a “complete living organism” yet has been observed to reproduce, mutate, and evolve with extremely successful results. What’s more, RNA just happens to be suited to carrying genetic information. Hmmm….
The formation of the first RNA molecules is still an area of active research, but intriguing progress has been made. In 2009, researchers synthesized the components of RNA, called ribonucleotides, from molecules that are known to exist in interstellar dust clouds and meteorites.
They mixed the molecules in water, heated the solution, then allowed it to evaporate, leaving behind a residue of hybrid, half-sugar, half-nucleobase molecules. To this residue they again added water, heated it, allowed it evaporate, and then irradiated it.
At each stage of the cycle, the resulting molecules were more complex. At the final stage, Sutherland’s team added phosphate. “Remarkably, it transformed into the ribonucleotide!” said Sutherland.
According to Sutherland, these laboratory conditions resembled those of the life-originating “warm little pond” hypothesized by Charles Darwin if the pond “evaporated, got heated, and then it rained and the sun shone.”
To me, that’s quite plausible. The dots are steadily being connected, folks.