Charles Darwin had no idea Earth's continents and ocean floors were moving when he was developing his famous theory of evolution by natural selection. It was the 1850s, and the English naturalist had never observed a creature evolve, genetics had yet to be discovered, the age of the Earth was unknown, and the fossil record of life had only begun to be assembled.
Discovery after discovery has bolstered the validity of Darwin's ideas during the 152 years since he first published them in On the Origins of Species, according to Alan Rogers, a longtime University of Utah anthropology professor.
"The case for evolution is stronger today than it has ever been," he wrote in his book The Evidence for Evolution, which counters many anti-evolution arguments. Rogers says these arguments are full of holes yet still have traction despite the overwhelming scientific consensus that life forms change over time.
"Alan Rogers addresses the political controversy over the theory of evolution (there's no longer any scientific controversy) in the best scientific spirit: with evidence and logic," said a review by Harvard psychologist Steven Pinker. "For anyone with an open mind, a curiosity about the natural world, and a desire to see controversies settled with evidence rather than rhetoric, this is an invaluable contribution and a fascinating read."
The theory of evolution transformed the science of biology but also inflamed controversy among religious authorities. To this day, it is rejected by those who hew to a literal interpretation of the Bible's creation story. Rogers' book, released this month by the University of Chicago Press, fills in gaps in Darwin's theory with scientific evidence that was not available in the 19th century.
"That evidence might have gone the other way," Rogers said. "It might have refuted Darwin's theory. But instead, we have 150 years of evidence, all of which supports his theory."
Rogers has taught about human evolution for years, but he didn't delve into the evidence that evolution had actually happened until he learned of a poll that found only half of Americans believed humans evolved.
"It dawned on me I was teaching my courses wrong. The question of whether [evolution] is true has not been a scientific question for 100 years. No one does research on that because it was settled," he said. "We tend to put in our courses what is happening now in science."
But what is the sense of teaching students about evolution if they don't believe it happens? So for the past few years, Rogers has spent the first two weeks of his course, Anthropology 1050, the Evolution of Human Nature, going over the evidence.
The first place he points to are the Hawaiian Islands, a chain created by the Pacific plate sliding over a hot spot in the Earth's mantle. Each new island was colonized by creatures from the nearest island that then evolve in isolation. Thanks to genetics, scientists can see how the islands' species of flightless crickets are related to each other.
"This gives you this beautiful shape to the phylogenetic tree that matches the simple history of those islands," he said.
Rogers tried to find a book for his courses, but they were either too long or assumed the reader needed no convincing. He decided to write his own 128-page book. While he hopes other academics will use it their classrooms, he wrote the book for a general audience.
"All scientists are skeptics if they're any good, but they're not stubborn about it," he said in a statement. "In science, you have to be able to change your mind when confronted with evidence. It seems to me that learning that skill is important, not only for scientists, but for everybody. It makes us better citizens."