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Chapter 18
Themes
Key
LitCharts assigns a color and icon to each theme in A Short History of Nearly Everything, which you can use to track the themes throughout the work.
Science, Discovery, and Mystery
Writing, Wonder, and Inspiration
Progress, Sexism, and Dogma
Existence, Awe, and Survival
Summary
Analysis
In 1953, graduate student Stanley Miller connects two flasks with tubes: one contains water, and the other contains methane, ammonia, and hydrogen sulphide gases (to represent Earth’s early atmosphere). When he adds electrical sparks to the mix (representing lightning), a “hearty broth” of amino acids and other organic compounds emerge. Scientists think that life originated this way on Earth. Unfortunately, progress into the origins of life hasn’t developed much further since then. Subsequent experiments using nitrogen and carbon dioxide—which were more likely abundant in Earth’s early life—yield only one primitive amino acid.
Bryson addresses Miller’s experiment to show that another area of human knowledge that the origins of life on Earth is another area of knowledge that’s highly speculative. The furthest humans have gotten to understanding how life gets going at all is one experiment that shows organic compounds emerge in a certain atmospheric environment—but this environment isn’t necessarily the one that Earth sustained. Yet again, this part of our origin story evades scientists—it remains all but shrouded in mystery.
Themes
Amino acids—“the building blocks of life”—join together to make proteins. It takes 1,055 amino acids joined in a specific order to make collagen, for example. It’s hard enough to do this on purpose, but the fact that it happens “spontaneously, without direction” is astounding. Additionally, “perhaps a million” different proteins are created this way, and the statistical odds of this happening effectively fall to zero. After proteins are created, they need to be reproduced, but only DNA can do this—and DNA and proteins also need a protective membrane around them (a cell) to function. All of these components have to come along at just the right time for life to arise. Bryson says that life really does seem to be a “miracle.”
Bryson stresses that the way that organic life appears to arise, as well as the fact that it did so on Earth, is nothing short of amazing. Humans often take the possibility of life for granted, but the fact that life is likely the result of spontaneous accidents involving molecules bumping into one another in just the right way at just the right intervals is astounding—the chances of life evolving at all are so rare that rather miraculous that it actually did happen. This phenomenon thus commands our awe.
Themes
Bryson thinks the best explanation for this “miracle” is evolution. Creationists (like Hoyle) essentially argue that all the proteins needed for life come into the world fully formed at once. Richard Dawkins (author of The Blind Watchmaker) argues that they develop over time, through trial and error of proteins bumping into each other and latching on in many different ways. Nature does seem to have an impulse toward “ordered self-assembly”—complex patterns are everywhere. Take crystals, or snowflakes, for example. Living organisms—from lettuce to human beings—are made of simple components: carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, calcium, and iron. If these elements are combined in about 36 different combinations, an organism can be formed.
Bryson alludes once again to the ways that religious intuitions can misdirect scientific thinking, since a great many scientists (including Hoyle) persist in maintaining that life is created all at once by a creator, despite how unlikely it is that such a phenomenon occurs at such. The evidence, in fact, points much more strongly to evolution, which only becomes scientifically legitimatized in the late 19th century, showing how religious values slow scientific progress when scientists try to marry their beliefs with the empirical evidence on Earth.
Themes
Factoring in Earth’s age—and the fact that Earth’s crust didn’t form until 3.9 million years ago—it means that life has to go from bacteria to human beings in approximately 3.5 billion years, which is surprisingly short for that degree of evolution. This is why some scientists—including the great Lord Kelvin—think that life had some help from space. Surely enough, in 1969, a 4.5-billion-year-old meteor explodes over Australia, and its chunks are “studded” with amino acids. Another asteroid that lands in Canada in 2000 also contains organic compounds.
Even when the evidence pointing to life’s origins on Earth is considered, there’s still a great deal that scientists don’t know—it might even be that the first organic compounds came from space, since there is some evidence to support this. This sort of speculation shows how little scientists actually know about the conditions that gave rise to our existence.
Themes
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However, Bryson thinks that “panspermia” (the theory that life got going with the help of some extra-terrestrial organic compounds from asteroids) is problematic, because it doesn’t explain how organisms evolve out of compounds, and it can encourage crackpot theories about “aliens.” Hoyle, for example, argues that panspermia brought the flu and the bubonic plague to Earth from space, and that human nostrils evolved facing the ground so that pathogens raining on Earth from above wouldn’t go up our noses. Bryson says that however life got started, we know that all life on Earth came from a single “primordial twitch.” Some chemicals somehow managed to spark into life and to produce an “heir” from part of itself. Biologists call this the “Big Birth.”
Bryson thinks that appealing to organic compounds from space is a bit of a cop-out, since it still doesn’t solve the mystery of how life gets going. Thus, even with the evidence scientists do have, there is much that remains to be explained, and therefore a lot of scientific work still to do. That being said, the fact that life did happen—even though we still don’t know how—is still miraculous, since it seems (as far as we know) that all life originates from a single “primordial twitch” that could have just as easily never happened.
Themes
A geochemist named Victoria Bennett, who’s trying to map Earth’s landscape 3.5 billion years ago (when life got started) explains to Bryson that if a scientist pulverizes ancient rock, it’s possible to detect chemical residues that life leaves behind (such as carbon isotopes). Bennett does this using a machine that also ages rocks by measuring the decay of uranium into zircon minerals. Her research shows that all in all, early Earth doesn’t seem conducive to life, especially before an atmosphere forms—yet there are still traces of organic life from that time. Bennet concludes that something must have suited life in those harsh early conditions, “otherwise we wouldn’t be here.”
Bryson stresses that the “primordial twitch” that began life is even more miraculous than it already seems, because as scientists like Bennett begin to learn more about the young Earth’s early geological and atmospheric environment, they realize that it’s largely inhospitable to organic life. Yet somehow, life did get going, which further underscores how much wonder and awe life commands for having happened at all.
Themes
Bennett explains that Earth’s early atmosphere is noxious, sulfuric, and only has trace amounts of oxygen, much like Mars’s current atmosphere. For two billion years, there’s just bacteria. At some point, “cyanobacteria” (blue-green algae) starts absorbing water—consuming water’s hydrogen and releasing oxygen as waste—thereby inventing photosynthesis. The process makes algae sticky, so clumps of dust stick to it, creating “stromatolites.” Stromatolites are living rocks made of cyanobacteria, dust, and sand. In 1961, scientists even discover a small colony of living stromatolites in Australia, which expel little bubbles of oxygen as they consume water. When stromatolites rise out of the water, they expel oxygen into the atmosphere instead of into water.
Bennett’s evidence points to how inhospitable early Earth’s environment is to oxygen-dependent beings, because the early atmosphere is largely absent of oxygen. This means that before oxygen-dependent life forms can form, organic life has to form that doesn’t rely on oxygen but somehow pumps the atmosphere full of it. Thus, our evolution depends not only on life beginning, but beginning in such a way that it facilitates an oxygen-rich atmosphere, rendering the history of our existence even more astounding.
Themes
Two billion years later, there’s enough oxygen in Earth’s atmosphere for mitochondria to evolve. They consume oxygen and facilitate respiration in cells. Eventually, life evolves into an equilibrium between organisms that expel oxygen (like plants) and organisms that consume oxygen. These oxygen-consuming organisms exist first as single-celled organisms called “protozoa,” and then, after another billion years, as multicellular organisms, which evolve to be increasingly complex, eventually giving rise to humans.
Bryson emphasizes the almost inconceivably long time it takes for both life, and the environment that life thrives in, to evolve from sustaining simple organic compounds to sustaining fully-fledged human beings. The sheer scale of this history implies there are vast stretches of geological and biological time about which scientists know very little.
Themes
