History of Darwin’s Theory Told in ‘Evolution’

bobschwarz@wvgazette.com

Darwin got it right.

Although he lived too early to have any understanding of how genes controlled heredity, Charles Darwin had sufficiently keen powers of observation and deduction to put together the theory of evolution.

As the young naturalist on the sailing ship Beagle, Darwin noticed that the Cape Verde Islands and Galapagos Islands were recently formed volcanic islands with habitats that were hostile and isolated. Both island groups supported limited varieties of mostly indigenous species.

Like any sharp observer, Darwin knew that similarities were only a starting point. It turned out that the Cape Verde Islands, 400 miles off the Atlantic Coast of Africa, supported plant and animal species that resembled those in Africa. The Galapagos Islands, 500 miles off the Pacific Coast of South America, sustained plants and animals that resembled those in South America.

Darwin collected many specimens and took careful notes. On the return trip to Britain, he noticed that the mockingbirds he had collected in the Galapagos fell into three unique groups. One group was found on a pair of islands, and two groups lived on just one island each.

Darwin brought back 14 species of finches, an ornithologist soon determined, and each was differentiated by the size and shape of its beak.

The birds had adapted to small niches through natural selection, Darwin concluded. He outlined the basic theory of evolution in his 1859 book “Origin of Species.” In the years since, scientists and mathematicians have hotly debated and refined the theory until now the entire scientific establishment, though far from the entire religious establishment, accepts it.

Edward J. Larson outlines all this in his splendid book “Evolution: The Remarkable History of a Scientific Theory.”

A professor of both history and law at the University of Georgia, Larson won a 1998 Pulitzer Prize for his “Summer for the Gods: The Scopes Trial and America’s Continuing Debate Over Science and Religion.” Next, he wrote “Evolution’s Workshop: God and Science on the Galapagos Islands.”

Not quite a textbook, Larson’s latest book traces the evolution of the evolutionary theory from the 1790s to the present. He presents a highly readable overview, sequentially relating one scientific advance after another, but keeping a reader’s interest by pausing long enough to engagingly tell the more noteworthy stories.

Larson includes all the missteps and misinterpretations that competent scientists fell into along the way.

Even Darwin thought there might be some merit to Lamarckism, the theory that characteristics acquired during one’s lifetime could be passed on to offspring. That didn’t pan out, but its proponents stubbornly carried the banner into the mid-20th century, especially in the Soviet Union, where it meshed with the beliefs of that nation’s leader, Stalin.

The monk Gregor Mendel provided a major advance. Mendel grew, crossbred, observed, sorted and counted nearly 30,000 pea plants from 1856 to 1863 and discovered what later became the foundation of gene theory: Some genes are dominant and some recessive; recessive genes for, say, short peas, which appeared to have disappeared in the first generation of a cross, mysteriously popped up in one of four plants when the offspring were rebred.

Mendel summarized his findings, but the scientific community had largely forgotten them until around 1900 when scientists caught up and Mendel’s work became relevant. (Darwin had died in 1882.)

In the 1910s, Kentuckian Thomas Morgan Hunt, working with fruit flies and leading a team of Columbia University researchers, tied Mendel’s laws of heredity into material chromosomes.

“It’s wonderful material,” Morgan boasted, referring to his fruit flies. “They breed all year round and give a new generation every 12 days. Within the first six years, Morgan and his team observed more generations than Mendel could have observed in 200 years.

A huge breakthrough occurred in 1953, when Francis Crick and James D. Watson discovered the double-helix shape of the gene. Crick and Watson found that genetic information was carried not in complex hard-to-decipher proteins but on a simple-to-decode macromolecule called DNA.

As scientists learned more about DNA, and the close genetic relationship that every living thing on this planet has to every other living thing, the scientific community reached a consensus. Darwin did have it right.

At the same time, however, people who believed in the primacy of the biblical story dug in their heels and resurrected the discredited theory of creationism, which basically said to evolutionists, “You haven’t proven it yet.” Humankind, the argument goes, is too noble a creature to be descended from apes.

As they lost ground in the scientific community, the creationists, led by Henry Morris, his son John Morris and the Institute for Creation Research the elder Morris founded in 1970, took a new tack. They reinvented creationism as creation science, which they contended was a rival theory which should be taught in schools alongside the theory of evolution. In time, the Institute for Creation Research became a major publisher of textbooks for Christian schools and Christian home-schoolers.

Larson covers all that, too, devoting one of his 12 chapters to “Modern Culture Wars.”

To contact staff writer Bob Schwarz, use e-mail or call 348- 1249.