Had Reverend Jenyns said yes: A small decision with a big impact on biology

In 1831, one of the most important events in the history of biology took place in the village of Swaffham Bulbeck, England: Leonard Jenyns (Fig. 1A) declined an invitation. In his diary, Reverend Jenyns wrote “This year I had the offer . . . as Naturalist . . . on [a] voyage to survey the coasts of S. America, afterwards going round the globe:—declined the appointment.”1 He had been recommended by his brother-in-law John Henslow, a botanist at nearby Cambridge University. But sea voyages were long, arduous, and dangerous, and he said no because his health was not strong and he had to tend to his rising clerical career and his parishioners in Swaffham Bulbeck, adjoining the Jenyns family estate at Bottisham Hall. Jenyns’ health couldn’t have been too delicate, since he lived into his 90s, but in any case he declined, and Henslow suggested another protege to Robert FitzRoy (Fig. 1B), Captain of the Beagle. And Charles Darwin said yes. I was in Cambridge this year, and while reading about FitzRoy2 the word “Bottisham” caught my eye because I’d biked through there many times. So I went another mile to Swaffham Bulbeck to pay homage and to see what the minister knew of his distinguished clerical ancestry. Bells were pealing the faith from the church tower but, perhaps partly because of what Darwin discovered, church attendance has plummeted, and today Swaffham Bulbeck (Fig. 2) has only a roving vicar who has six parishes to care for. He wasn’t there, but an elderly woman watering flowers at the church assured me, as we talked among tombstones that had borne witness to the great event, that they indeed knew of their church’s brush with history. Today the minister is no longer a Jenyns, but the family still rules at Bottisham Hall (Fig. 2), where Darwin and Jenyns had occasionally scavenged for insects.3 And by ironic good fortune I was able to cross paths with Darwin, visiting Leslie Knapp,4,5 a bioanthropologist at Cambridge who now rents a wing of old Bottisham Hall, where she lives with her husband and two cats. This experience led me to wonder how fragile is the thread of history, even in science. What might biology be like today if Reverend Jenyns had said yes to Captain FitzRoy’s offer? Reverend Jenyns would have shipped specimens back by the trunkload, but he would have been too busy discussing biblical facts with FitzRoy to have achieved Darwin’s insights. Meanwhile, Darwin would have passed into the dusty pages of family genealogies and books on shooting. We know evolution would still have been discovered, because Alfred Russel Wallace (Fig. 3a) did just that, during a malarial fit in Ternate, East Indies, in 1858. Later that year, thirtyodd members of the Linnaean Society dozed peacefully while the paper Wallace sent to Darwin and some of Darwin’s private notes and letters were read to them. But the following year Darwin’s name, influence, and On the Origin of Species by Means of Natural Selection put evolution on the front page, with Darwin as its chief spokesman. If Jenyns had said yes, Darwin wouldn’t have been on the scene. Wallace would have sent his paper to some other London contact, perhaps geologist Charles Lyell or botanist Joseph Hooker. When he received Wallace’s paper in the mail, Darwin was stunned by its similarity to thoughts he’d been brooding over for some time, but actually the two views were rather different.6 Both Wallace and Darwin stressed natural selection and both were concerned with the existence of varieties and species. Wallace titled his paper, “On the Tendency of Varieties to Depart Indefinitely From the Original Type.”7 But Wallace had a more ecological concern. He wrote that “The life of wild animals is a struggle for existence both of individuals and of entire species.” Though he knew that individuals live to reproduce or not, “it is clear that what takes place among the individuals of a species must also occur among the several allied species of a group,—viz. that those which are best adapted to obtain a regular supply of food, and to defend themselves against the attacks of their enemies and the vicissitudes of the seasons, must necessarily obtain and preserve a superiority in population.” This, in turn, leads to “the excessive abundance of some species, while others closely allied to them are very rare.” To Wallace, this relative abundance of species was “entirely due to their organization and resulting habits.”7 This is ecological thinking because “this new, improved, and populous race might itself, in course of time, Ken Weiss is Evan Pugh Professor of Anthropology and Genetics at Penn State University.