Sunday, August 14, 2016
Luca Is Mom to Us All, But Was She Really a Zombie?
If a family tree were done all the way back to the beginning of life, the generational connections of trillions upon trillions of living things across all species of plants and animals would show, perched on top like a lonely and forlorn Christmas-tree angel, the Mother of All Life: Luca. Luca is the acronym for “Last Universal Common Ancestor.” According to scientists, Luca, a simple single cell, first existed four billion years ago when Earth itself, at 560 million years of age, surely was still teething.
Some scientists believe that Luca emerged from deep-sea vents swirling with gases and furnace temperatures caused by the volcanic magma erupting on the sea floor. The dramatic interaction of those elements, together with both sea water and critical metals found there, would have been enough to create the first life. We’ll call this sine-qua-non Evolutionary Vent, whenever and wherever it first happened, the Big E-Vent. Devotees of the Big E-Vent, notably evolutionary biologist Dr. William Martin of Heinrich Heine University in Germany, have isolated a mere 355 genes, out of the typical tens of millions of genes in a living organism, that are common to living things and therefore believed to have been the very genes of Luca. Because the functions of those few genes are inadequate to sustain life, the Big E-Vent scientists believe that Luca must have only been “half alive” or half of a living thing, depending for its life on chemicals from its environment to sustain it.
If true, Luca was the first chimera. Instead of something a like part human, part monkey creature, proto-chimeric Luca, with each ocean wave must have lurched from vent to vent, doomed to a semi-existence as half living bacterium-like cell, half zombie-like amalgam of metals and chemicals.
Others dispute the promoters of the Big E-Vent with all their plumes of gases, heavy metals, and raucous volcanic noise. They say that life originated more casually in warm shallow pools. Darwin himself believed this, believing that life evolved from “warm little ponds.” The scientists who believe in the less dramatic and laid-back pool theory we’ll call the Pool Parties. The Pool Parties also point to the essential function of ultraviolet light, critical not just for sunbathing or drying out after a swim but for its role as an energy source capable of causing the chemical reaction that animated the first living cell spawning all of life on Earth.
One such patron among the Pool Parties, Dr. John Sutherland, a chemist at the University of Cambridge, said that the chemistry does not support the Big E-Vent theory, and he criticized the study for its lack of testing with chemical simulations. Sutherland also had this to say about the proposition that Luca could only have been half-alive, half chemical zombie: “It’s like saying I’m half-alive because I depend on my local supermarket.”
In conclusion, I will say that Dr. Sutherland sounds very reasonable, but I highly doubt he’s ever wandered into a Safeway well after midnight and seen as I have the creatures who are in there shopping at that hour.