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by Chaotropy — This article is the first in a series on the origins of life, abiogenesis, chemical evolution, and the RNA world hypothesis.
We are all familiar with Darwin’s theory of evolution, which beautifully explains how life evolved from single-celled organisms to us mammals. But how did the first living thing come into being? How did life emerge from dead matter? What precedes evolution? For decades, physicists, chemists, and biologists have studied the process by which life arises naturally from non-living matter — called abiogenesis.
This story begins with the most basic building blocks of the universe: atoms. Atoms of the elements carbon, hydrogen, oxygen, phosphorus, sulfur, and nitrogen are the smallest particles that make up all life on Earth. They all behave strangely to each other under the conditions of our Earth’s surface. Among the 98 elements that make up our planet, they form a kind of family, especially under the temperatures and pressures of the Earth’s surface, that might never have come together in this way on many other worlds. As if the rules of stoichiometry were the instructions of a gigantic divine construction kit that allows the creation of an infinite number of almost infinitely complex structures, these six elements can combine under our skies to form countless molecules, and were also abundantly dissolved in the primordial oceans of our young planet. It is in this primordial soup, as it is sometimes called, that the story of life begins.
The driving force that leads to ever-new combinations of these six elements is striving to achieve the energetic optimum, i.e., the lowest possible energy state. When two chemical particles combine in a chemical reaction to form a third, the sum of the energies inherent in these two individual reactants is unequal to the internal energy of the resulting product. Consequently, energy must be added if the internal energy of the product is greater than that of its reactants. But even if the internal energy of the product is less than the sum of its components, a certain amount of activation energy must first be expended before the reaction can begin. It is, so to speak, the burning match without which we cannot ignite even the driest of logs. Incidentally, this is an apt example because fire is ultimately a reaction in which the…
