Bill Bryson - A short history of nearly everything

The belief was surprising in as radical a spirit as Huxley because it closely recalled a very conservative religious notion first put forward by the English theologian William Paley in 1802 and known as argument from design. Paley contended that if you found a pocket watch on the ground, even if you had never seen such a thing before, you would instantly perceive that it had been made by an intelligent entity. So it was, he believed, with nature: its complexity was proof of its design. The notion was a powerful one in the nineteenth century, and it gave Darwin trouble too. “The eye to this day gives me a cold shudder,” he acknowledged in a letter to a friend. In the Origin he conceded that it “seems, I freely confess, absurd in the highest possible degree” that natural selection could produce such an instrument in gradual steps.

Even so, and to the unending exasperation of his supporters, Darwin not only insisted that all change was gradual, but in nearly every edition of Origin he stepped up the amount of time he supposed necessary to allow evolution to progress, which pushed his ideas increasingly out of favor. “Eventually,” according to the scientist and historian Jeffrey Schwartz, “Darwin lost virtually all the support that still remained among the ranks of fellow natural historians and geologists.”

Ironically, considering that Darwin called his book On the Origin of Species , the one thing he couldn’t explain was how species originated. Darwin’s theory suggested a mechanism for how a species might become stronger or better or faster-in a word, fitter-but gave no indication of how it might throw up a new species. A Scottish engineer, Fleeming Jenkin, considered the problem and noted an important flaw in Darwin’s argument. Darwin believed that any beneficial trait that arose in one generation would be passed on to subsequent generations, thus strengthening the species.

Jenkin pointed out that a favorable trait in one parent wouldn’t become dominant in succeeding generations, but in fact would be diluted through blending. If you pour whiskey into a tumbler of water, you don’t make the whiskey stronger, you make it weaker. And if you pour that dilute solution into another glass of water, it becomes weaker still. In the same way, any favorable trait introduced by one parent would be successively watered down by subsequent matings until it ceased to be apparent at all. Thus Darwin’s theory was not a recipe for change, but for constancy. Lucky flukes might arise from time to time, but they would soon vanish under the general impulse to bring everything back to a stable mediocrity. If natural selection were to work, some alternative, unconsidered mechanism was required.

Unknown to Darwin and everyone else, eight hundred miles away in a tranquil corner of Middle Europe a retiring monk named Gregor Mendel was coming up with the solution.

Mendel was born in 1822 to a humble farming family in a backwater of the Austrian empire in what is now the Czech Republic. Schoolbooks once portrayed him as a simple but observant provincial monk whose discoveries were largely serendipitous-the result of noticing some interesting traits of inheritance while pottering about with pea plants in the monastery’s kitchen garden. In fact, Mendel was a trained scientist-he had studied physics and mathematics at the Olmütz Philosophical Institute and the University of Vienna-and he brought scientific discipline to all he did. Moreover, the monastery at Brno where he lived from 1843 was known as a learned institution. It had a library of twenty thousand books and a tradition of careful scientific investigation.

Before embarking on his experiments, Mendel spent two years preparing his control specimens, seven varieties of pea, to make sure they bred true. Then, helped by two full-time assistants, he repeatedly bred and crossbred hybrids from thirty thousand pea plants. It was delicate work, requiring them to take the most exacting pains to avoid accidental cross-fertilization and to note every slight variation in the growth and appearance of seeds, pods, leaves, stems, and flowers. Mendel knew what he was doing.

He never used the word gene -it wasn’t coined until 1913, in an English medical dictionary-though he did invent the terms dominant and recessive . What he established was that every seed contained two “factors” or “elemente,” as he called them-a dominant one and a recessive one-and these factors, when combined, produced predictable patterns of inheritance.

The results he converted into precise mathematical formulae. Altogether Mendel spent eight years on the experiments, then confirmed his results with similar experiments on flowers, corn, and other plants. If anything, Mendel was too scientific in his approach, for when he presented his findings at the February and March meetings of the Natural History Society of Brno in 1865, the audience of about forty listened politely but was conspicuously unmoved, even though the breeding of plants was a matter of great practical interest to many of the members.

When Mendel’s report was published, he eagerly sent a copy to the great Swiss botanist Karl-Wilhelm von Nägeli, whose support was more or less vital for the theory’s prospects. Unfortunately, Nägeli failed to perceive the importance of what Mendel had found. He suggested that Mendel try breeding hawkweed. Mendel obediently did as Nägeli suggested, but quickly realized that hawkweed had none of the requisite features for studying heritability. It was evident to him that Nägeli had not read the paper closely, or possibly at all. Frustrated, Mendel retired from investigating heritability and spent the rest of his life growing outstanding vegetables and studying bees, mice, and sunspots, among much else. Eventually he was made abbot.

Mendel’s findings weren’t quite as widely ignored as is sometimes suggested. His study received a glowing entry in the Encyclopaedia Britannica -then a more leading record of scientific thought than now-and was cited repeatedly in an important paper by the German Wilhelm Olbers Focke. Indeed, it was because Mendel’s ideas never entirely sank below the waterline of scientific thought that they were so easily recovered when the world was ready for them.

Together, without realizing it, Darwin and Mendel laid the groundwork for all of life sciences in the twentieth century. Darwin saw that all living things are connected, that ultimately they “trace their ancestry to a single, common source,” while Mendel’s work provided the mechanism to explain how that could happen. The two men could easily have helped each other. Mendel owned a German edition of the Origin of Species , which he is known to have read, so he must have realized the applicability of his work to Darwin’s, yet he appears to have made no effort to get in touch. And Darwin for his part is known to have studied Focke’s influential paper with its repeated references to Mendel’s work, but didn’t connect them to his own studies.

The one thing everyone thinks featured in Darwin’s argument, that humans are descended from apes, didn’t feature at all except as one passing allusion. Even so, it took no great leap of imagination to see the implications for human development in Darwin’s theories, and it became an immediate talking point.

The showdown came on Saturday, June 30, 1860, at a meeting of the British Association for the Advancement of Science in Oxford. Huxley had been urged to attend by Robert Chambers, author of Vestiges of the Natural History of Creation , though he was still unaware of Chambers’s connection to that contentious tome. Darwin, as ever, was absent. The meeting was held at the Oxford Zoological Museum. More than a thousand people crowded into the chamber; hundreds more were turned away. People knew that something big was going to happen, though they had first to wait while a slumber-inducing speaker named John William Draper of New York University bravely slogged his way through two hours of introductory remarks on “The Intellectual Development of Europe Considered with Reference to the Views of Mr. Darwin.”