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A Reader Writes by Brian McNeece: Married, with children: watching evolution in action

June 17, 2002

The journal "Science" recently reported that two scientists on a tiny island in the Galapagos have observed evolution in action. The husband and wife team of Peter and Rosemary Grant have noticed generation-to-generation adaptations of finches' beaks to changing conditions.

Beyond the news itself — that natural selection works very quickly and not slowly as Darwin thought — I was struck by the contrast of science done in Darwin's time and in our own.

Darwin set sail as an unpaid naturalist on the ship "Beagle" in 1831 at age 22 after having failed in his father's wishes for him to become a doctor or a clergyman. For five years, the young Darwin traveled around the world gathering specimens and taking notes. Upon returning to England he spent the rest of his life studying and writing about his vast collection of specimens and data.

A very reserved man, he rarely left the grounds of his home because of chronic fatigue and intestinal problems. (In his own time, he was accused of hypochondria, but we now know he suffered from a disease contracted in his travels.)


Darwin published his theory of natural selection (what we today call evolution) many years after he had formulated it. He did not want to offend the religious opinions of his times. Only when Alfred Russel Wallace brought forth the same theory backed up by much less evidence did Darwin publish "On The Origin Of Species By Means Of Natural Selection: Or, The Preservation Of Favored Races In The Struggle For Life" in 1859. By the moral standards of any age, he was a monk-like and virtuous soul.

In contrast to Darwin's prolonged wanderings away from the comfort of home and family and the chronic suffering of his later years, Peter and Rosemary Grant have traveled to the Galapagos Islands each year together since 1973. (Their daughters go, too.) What a welcome adaptation from the all-male world of Darwin's science of 167 years ago — a blink in geological time, but a three-act play in social time. How lovely that Peter and Rosemary have each other there in a tent on the desolate, volcanic island of Daphne Major.

Because of the remoteness of the islands, they must do without most of today's modern conveniences, including, Peter lamented, cold beer. On the other hand, after a day of hard scientisting, they can return to the conjugal nest to enjoy the legitimate pleasures of the married flesh.

Where Darwin labored in apparently constant pain and suffering, the Grants bubble delightedly about their lifetime quest in the observation of birds.

"We're crazy about being completely absorbed by biological research in uninterrupted fashion," says Peter Grant.

That's where Darwin and the Grants converge: the science itself.

The Grants have observed about 30 generations of finches firsthand. They recognize each individual bird on the island, which they have captured and photographed and weighed. Rosemary and Peter and their collaborators have measured the length and angle of every beak of thousands of adult birds. They note who mates with whom and how often, and what kind of seeds they eat.

How fitting that the basic science that fuels new knowledge in the 21st century is being done by a husband and wife who enjoy the meticulous order of basic science and also the pleasure of each other's company on a tiny island in the Pacific. It's a lovely, romantic yet rugged picture of what must be a very satisfying life. When they get back to the states, I'd like to buy them a cold one.

The scientific news is that the Grants have observed changes in the structures of two different species of birds' beaks. During drought conditions, plants struggle and the only seeds available are the large, tough seeds left from the year before. Finches with narrow, thinner beaks die out, but the birds with stouter beaks survive. In the very next generation, birds with larger beaks predominate.

When rainfall is plenty and seeds are tender and abundant, the smaller, quicker birds with thin beaks thrive, and the process is reversed. Darwin and Wallace thought that this process they called natural selection was extremely slow and moved in one direction — toward ever more fitness.

Despite his characteristic caution and thoroughness, Darwin underestimated the richness of nature's ability to adapt. Peter and Rosemary Grant (their daughters help, too) have shown us that nature adapts very quickly (a lot can happen in a million years), and that the changes can go in whatever direction survival value holds. Sometimes new species develop from a single trunk source, and sometimes two species may converge into one.

"You can no more predict the course of natural selection than you can predict the weather," says Peter Grant.

God's still the designer, having blown the yearning to exist into all that's around us, but natural selection is apparently the game he designed.

>>Brian McNeece is an El Centro resident who teaches Enligh at Imperial Valley College.

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