Wednesday, April 05, 2006
The Origin of Origin of the Species
So, why was he the first to use the observations he made during the voyage of the Beagle to construct the theory of evolution?
Not long before Darwin set sail on his five-year voyage of discovery aboard the Beagle, the Reverend John Henslow, Darwin's professor at Cambridge, recommended he take along Charles Lyell's Principles of Geology which argued, among other things, that the natural geological processes we observe today have operated throughout history. that change comes slowly over immense stretches of geologic time, and that natural laws are constant and eternal.
"I really think my books come half out of Lyell's brain," Darwin once said, "I see through his eyes."
Now we are learning that Henslow may have done much more to prepare Darwin for his great discovery than simply to recommend Lyell's book. Last fall, we linked to a story that Henslow used botanical specimens from around England to illustrate variability to his students.
"Henslow was not just identifying plants," says Dr Mark Whitehorn, a geneticist who collaborated with scientists from Cambridge University to show how Darwin's university mentor had set him on course to his revolutionary theory long before he sailed aboard the Beagle, "he was organising his herbarium to emphasise variation within species."
Now, there's a new report on this research from Jeremy Kirk of IDG News Service that Henslow's herbarium, consisting of 3,500 sheets with more than 10,000 dried plant samples, which Henslow carefully documented with each samples' origin, quantity, date collected, and species, among other data, has been entered into a Microsoft SQL database.
For 160 years it was believed Darwin's interest in variation arose aboard the Beagle when he arrived at the Galapagos Islands.
"What we believe happened is Henslow sent Darwin off on the Beagle saying 'go and see if this happens across the world'. Darwin sent almost all of the samples he collected while on the Beagle to Henslow.
" We believe Henslow launched Darwin's mind during those undergraduate days on an intellectual voyage that led from a belief in species stability to the mutability expressed in Origin of Species."
Kirk reports that a striking conclusion became evident. "The concept of variation -- meaning differences within members of a species necessary for survival as a whole -- was observed first by Henslow," according to Whitehorn.
"What is now very clear to us is that Henslow started studying this variation quite systematically in about the 1820s," Whitehorn said. "He actually trained Darwin to observe variations between the species."