"For the Christian theologian, the facts of nature are the acts of God" - Aubrey Moore
“Great are the works of the LORD, studied by all who delight in them. Full of splendour and majesty is his work, and his righteousness endures forever.” - Psalm 111: 2-3
“How did life begin?” is one of those big questions that has been asked by thinkers throughout the ages. However, in today’s scientific environment, it is not just a problem about which there is idle speculation. As geological evidence and biochemical understanding continue to grow, and more sophisticated models are devised and tested, we might be closer to answering this question than we think.
In the modernist version of Christianity, it seems that the question of how life began is either considered answered, or not considered. Face-value readings of Genesis are growing in prominence and give easy answers in place of theological understanding and recognition of our position in creation. At the same time, Christians who accept evolution often think no further and do not reach controversies about genealogies, Adam, the Fall, and death. The issue of abiogenesis, life from “unlife”, is perhaps of similar ilk.
The most famous empirical investigation into abiogenesis is the Urey-Miller experiment, which consisted of simulating lightning on a “Primordial Soup” mixture, producing amino acids. Since no geological evidence supports the existence of the “Primordial Soup”, which seems far more the result of a thought-experiment than empiricism, this model has been thrown out. However, when it was popular, it was thought that the production of amino acids in an abiotic system suggested abiogenesis could be possible.
Today a rather more grounded model exists – expounded by the remarkable science communicator Nick Lane. Here’s the gist of it:
Biochemists have recognised that one of the fundamental features of life is the presence of electrochemical gradients across a membrane that are kept away from equilibrium. This acts a bit like a battery as a source of energy to form ATP. This chemical powers reactions in the cell and plays a role in membrane-based biochemistry, such as pumping things in/out of the cell. This type of system is used by bacteria across their cell surface membranes, in each of your cells across the inner mitochondrial membranes, and across the thylakoid membranes of chloroplasts as part of photosynthesis. Due to the ubiquity of these electrochemical gradients in living systems, it was conceptualised that looking for how these could appear in an inorganic world might be a better way of investigating the origin of life than looking first for RNA, protein, or DNA.
In 2001 a new type of hydrothermal vent was found. It is formed by a geological reaction common not just on Earth but probably on other rocky worlds too. These “white smokers” have a porous sponge-like structure, contain lots of iron and sulphur, have hot alkaline water coming up through them, and the cold (neutral, or a long time ago, acidic) sea water around them. This results in a pH gradient of several units across the walls of the vent pores, as vent water moves up and through the pores while sea water percolates into the material. As Figure 1 shows, this looks rather like the living systems we have described before.
Figure 1: Proton gradients from across the tree of life, and before it. Red represents an acidic environment, blue represents an alkaline environment. a) A pore in a “white smoker” alkaline hydrothermal vent, with acidic seawater on one side of the pore and alkaline vent fluid on the other. b) A bacterium, with an acidic environment maintained just outside its cell surface membrane and a higher pH environment inside. c) A mitochondrion, with an alkaline interior and an acidic inter-membrane space. d) A chloroplast, containing thylakoids with acidic interiors suspended in an alkaline surrounding. All these systems have potential energy available because of the difference in pH across a pore wall or biological membrane. Credit: Ben Norris
This biochemical-geochemical analogue is important because phylogenetics becomes very murky when looking far into the past, as statistics become insignificant and lateral gene transfer muddies lineages. At some point we cannot look any further backwards and so must go forwards, taking the barest fundamentals like what we see in these vents and trying to work out a chemically feasible path that the Last Universal Common Ancestor (LUCA) of all life might have taken on its way out of the vent.
We know that the materials the vent is made of can be good catalysts for common reactions in organic chemistry, and there is evidence that amino acids are spontaneously produced there. We also know that a process called thermophoresis would concentrate larger biomolecules fundamental to life in certain compartments of the vent. While there, further catalysis could facilitate the formation of biological polymers like RNA or DNA. And just like oil droplets coalescing in water, if organic lipid molecules were formed and concentrated, they would spontaneously form structures like the membranes we see on the outside of all cells today.
To many biochemists, this begins to look like a peculiar and rare set of conditions that would give rise to life. It is a matter of chance and necessity. Chance to bring together the geochemical and thermodynamic environment to render “life”, as a chemical reaction, favourable. Necessity, as when conditions became optimum for life, the formation of living systems was then bound to happen.
So, what does this science mean for us as Christians? We do have a precedent showing that abiogenesis is not an unscriptural idea – the author of Genesis 2 uses it to describe God’s making of man. Forming man from dust and LUCA from an alkaline vent are surely identical creative acts. But for the Christian “How did life begin?” is not actually an important question! Whether through miraculous intervention or the laws God chose for this universe, we are certain that the origins of life are totally dependent on God as Creator. Furthermore, life today is just as totally dependent on God as life whenever it started, which is a cause for gladness and for praise.
“He is the radiance of the glory of God and the exact imprint of His nature, and he upholds the universe by the word of his power.” – Hebrews 1:3
“In him we live and move and have our being.” – Epimenides, quoted in Acts 17:28
Creation is not the distant accomplishment of a distant God but a present truth about an intimately present God and His creation. How cellular life might have come to be is just another marvellous part of it.
About the author
Ben is currently a student at Cambridge studying natural sciences, and is most interested in the puzzles at the interface of chemistry and biology.He enjoys playing French horn in ensembles around Cambridge, reading, and exploring the outdoors.