Monday, February 9, 2009

Why is Darwin So Important?

A Young Man on Some Old Islands

In 1831, Charles Darwin thought he had “wasted” (his word) his college education. The 22-year-old was thus sent off by his father on a five-year journey that would change our understanding of our place in the nonhuman world. After five weeks on the Gal├ípagos Islands, far out in the middle of the Pacific off the coast of Ecuador, Darwin’s observations and drawings of finches and tortoises led him to formulate the idea of natural selection, the centerpiece of his version of evolution. As he walked the sandy shorelines of these craggy volcanoes, he suddenly realized that the birds around him had variable beaks because natural selection had selected certain beaks as more useful than others: some for gathering seeds, others for crushing nuts, a few for spearing termites. The he saw iguanas swimming in the ocean, unlike almost any other lizards on earth. Lizards were land animals, but these spiny creatures found their food in the sea, just as the dinosaurs had. The young naturalist climbed these rocky hillsides, and he noticed that many of the creatures he saw were isolated from one another, trapped on their individual islands. Gal├ípagos tortoises grew gigantic because there were no large, vicious mammals here to compete with them for food or space. Darwin’s ideas at this point were not new, nor were they complete. Indeed, his grandfather had implied that species change over time (as had some ancient Greeks). Now, however, the grandson’s emerging explanation of the way species evolve by means of natural selection would literally change our world.

Separate Creation or The Origin of Species?

Charles Darwin made himself literally ill with what he knew. He paced up and down the garden paths at Down House--not far from London--for over a quarter of a century, fretting himself sick because he possessed a secret that would upset the world. He spent countless hours in his book-lined study, pouring over boxes of beetles and barnacles, convinced that every living creature on earth must be related to every other creature, living or dead. Darwin was so disturbed by the power of his own idea that he refused to publish his conclusion for more than two decades. When his beloved 10-year-old daughter Annie died of a ravaging scarlet fever, Darwin lost whatever trace of faith he might have had in a just God, or a well-planned universe. He put his major scientific conclusion on paper for the first time in a letter that conveys his sense of the danger of his own insight. To even suggest that species might be mutable, he said, was like “confessing a murder.” In fact, he was right. Within months of Darwin’s public presentation of his findings, shouting matches broke out on the floor of learned societies throughout Europe. His critics called him “godless.” His enemies said that his ideas were evil. They put his head on the body of a chimpanzee. At he same time, they could not prove him wrong. In one five-page paper, Darwin had explained the process by which all life on earth had developed.

Two Centuries of Evolution, and Counting

Bible believers can say what they will; but, according to Darwin, creation is underway today--in fact, it never ends. Species are constantly changing, adapting and modifying, under the pressures of selection by natural forces, because of the random chances of mutation. During the same decade that On the Origin of Species was published, an obscure Augustinian monk in Austria was planting 30,000 pea pods in his monastery garden. This genius, Gregor Mendel, figured out the precise part of cells that causes changes in organisms, but he did not call these cell-parts “genes” yet. He went on selectively to breed a hybrid variety of honeybees that had to be destroyed because they were so aggressive, much like our current strain of Africanized bees.

Indeed, a garden full of vicious bees was the birthplace of modern biology. Half a century would have to pass before Mendel’s genetic discoveries were connected to Darwinian thinking. When Mendel’s peapods were finally linked to Darwin’s finches, however, the results would be staggering: genetically modified foods--“Frankenfoods”--cloning, fertility treatments, hitherto unimagined cures for virulent diseases. In 2005, in his landmark decision in the case of Kitzmiller vs. Dover Area School District, Judge John Jones said that so-called “intelligent design” is nothing more than a version of creationism and that creationism can never be taught in public schools. So our story is far from over. Darwin and his successors have had powerful impacts on biology, ecology, paleontology, and social theory. In addition, evolution continues to influence religious thinkers and atheists, literary and visual artists, psychologists and politicians. Hard to imagine? Perhaps, but Darwin’s ideas, like the ideas of his powerful predecessors, have affected all human beings who have tried to understand nature from 1809 until 2009.