Aside from the satisfaction of proving geometric theorems, Steven Stanley had never felt so intellectually engaged as he did in an undergraduate Princeton course that addressed evolution.
By his senior year, Stanley had written a term paper on Charles Darwin and was headed into a career in paleobiology that includes three books on evolution, theoretical contributions to the field and research on the history of Earth.
“I’m fascinated with the 19th century, when geology and modern biology were born. Darwin was the first modern biologist,” reflects the University of Hawaiʻi at Mānoa professor of geology and geophysics.
Barbara Keating’s fascination with Darwin came later. “I used to do a lot of cruises in the southern and western Pacific, working on corals and volcanoes. Places I would go to, he had already been,” the Mānoa associate geophysicist says.
Noting that Darwin considered himself a geologist, she’s working on a book that follows his footsteps as her retirement project.
Both Stanley and Keating are celebrating the 200th anniversary of Darwin’s birth on Feb. 12, 1809 by giving talks (see details) on the man Nature calls “arguably the most influential scientist of modern times” unmatched for combined impact on the natural and social sciences, politics, religions and philosophy.
Darwin as a young man
Most images depict Darwin as an old man—captured after the advent of photography because he hated sitting for portraits, Keating says. In her mind’s eye, she sees the adventurer.
Son of a wealthy doctor and member of the Wedgwood china family, Darwin was nothing if not curious. Put off by medical training and bored with his classical education, he sought out mentors, obtaining his real education outside the classroom.
“He was known for a time as the man who walks with Henslow,” says Stanley. Cambridge geologist and botanist John Stevens Henslow spurred Darwin’s interest in natural history and introduced him to the captain of the HMS Beagle.
Darwin studied in the field with geologist Adam Sedgwick and collected marine life with biologist Robert Grant.
Darwin’s father opposed his proposal to accompany Captain Robert FitzRoy until convinced to relent by Darwin’s uncle (and future father-in-law). Darwin spent the five-year voyage to South Africa, through the South Pacific and around South America, surveying, mapping, collecting specimens, reading and, most of all, observing.
FitzRoy gave Darwin Charles Lyell’s Principles of Geology, which posited that the Earth is shaped by slowing moving but measurable forces. Darwin’s observations supported Lyell’s.
“In Chile, he was looking for fossils and found a series of terraces that led him to conclude that South America was rising. He was ahead of the game,” Keating says.
Seeing the various stages of atoll development, he understood the life history of volcanic islands, Stanley adds. “Darwin was a remarkable observer and very good analytical mind. He had a very powerful intellect and tested hypotheses.”
Evolution and natural selection
Darwin boarded the Beagle a fundamentalist, accepting the biblical account of Earth’s history, Stanley says. But what he saw convinced him that Earth was very old and that life must have arisen through a natural process.
“Science told him fundamentalism was wrong.”
Darwin had also boarded the Beagle a nobody, but his correspondence during the trip and a popular narrative completed upon his return made him famous. He subsequently wrote, did field work and served as secretary of the Geological Society.
His extensive reading included revival of An Essay on the Principle of Population, in which Thomas Malthus described species’ struggle for existence.
“It was a light bulb that went off one day. You can tell from his notes,” says Stanley.
Others had talked about evolution, but now Darwin had a mechanism̬natural selection—that explained how it occurred. He wrote in his journal: “It at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here, then, I had at last got a theory by which to work.”
Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life wasn’t published until 1859, 23 years after the Beagle returned to England.
Keating speculates that the delay was due in part to the reticence of Darwin’s strongly religious wife Emma, who feared his views would separate them in the afterlife.
Still, says Stanley, the delay allowed Darwin to consider every contingency, think through every hypothesis and address every criticism. “That’s why his work was so effective.”
It might have been delayed still longer had not Alfred Wallace independently proposed divergence of species due to environmental pressures in a paper. Friends arranged a joint presentation to the Linnean Society, which Darwin missed due to the death of his infant son.
The two scientists later met and continued a friendly, respectful exchange of ideas. Darwin even made sure Wallace, a leading thinker of the day though somewhat forgotten by history, got a government pension, Keating says.
Above all, Darwin was a nice man, kind, gentle, unassuming, she and Stanley agree. He was very likeable-an affectionate father and grandfather whose grandchildren bribed him to play with them.
The scientific legacy
Darwin refined and revised his own work, so it is hardly surprising that his ideas of evolution should undergo some revision. Even Wallace and vocal Darwin advocate Thomas Huxley had diverging thoughts. Modern evolutionary synthesis incorporated the ideas of Gregor Mendel, whose work on inheritance of traits gave rise to genetics.
Stanley was one of the early proponents of punctuation evolution, which tempers Darwin’s picture of evolution as a slow, gradual process. Evolution occurs most effectively in small populations in local areas within short historical periods, such as the rapid development of 500 species of cichlid fish in a geologically young Lake Victoria, he explains.
Punctuation evolution explains why Darwin couldn’t find a continuous fossil record to support gradual evolution.
UH Mānoa evolutionary biologist Kenneth Kaneshiro conducts research on the role of sexual selection, the concept that mate selection can trump natural selection.
Shifts in the sexual environment may play a dominant role in species formation as well as having an impact on the genetic background of a small population facing extinction, he suggests.
Other UH researchers hone in on specific evolutionary questions.
At the Pacific Biosciences Research Center’s Kewalo Marine Laboratory for example, Mark Martindale and Andreas Hejnol study acoel flatworms, which have been determined to be an evolutionary steppingstone in development of bilaterally symmetrical animals—those with distinct right/left and top/bottom bodies.
In a Nature paper published in September 2008, the researchers challenged conventional wisdom that a single opening split into separate mouth and anus openings at opposite ends of the gut before bilateral symmetry could occur. They showed that the anus developed independently as animal bodies grew in size, providing for more efficient handling of food and waste.
The researchers continue to look at the worms for clues about the evolutionary roots of the human brain and spinal cord.
In earlier work, Martindale and other colleagues looked the evolution of novel morphological structures. In animals from flies to humans, Hox genes organize the body into discreet regions along a head-to-tail axis in animals from flies to humans. In the Hawaiian bobtail squid, however, the same genes re-deployed to develop arm-like tentacles, a light organ, ink glands and a jet propulsion system.
Across UH and around the world, other researchers continue to fill in the picture Darwin sketched.
And a wonderful picture it is, Stanley argues. “The end of Darwin’s book is moving. There is grandeur in this view of life. This is meaningful, beautiful, exciting, glorious.”
Anniversary Talks on Charles Darwin
- Steven Stanley speaks on Darwin and the Origin of the Origin
Thursday, Feb. 12, 3:30 p.m., free
- Barbara Keating will lead a Darwin tour of Foster Gardens in March
Details to be arranged
Email for information