The Voyage of the Beagle

The H.M.S. Beagle, commanded by Captain FitzRoy and with Charles Darwin acting as naturalist, while anchored off the coast of Chile. Starr and Taggart, 1989, Biology - the Unity and Diversity of Life.
 

Charles Darwin as a young man, about the time he embarked on the Beagle voyage in 1832. Starr and Taggart, 1989, Biology - the Unity and Diversity of Life.

Almost every textbook that provides a picture of Darwin uses a very famous photograph taken near the end of his life. Looking at this very old man, it is difficult to imagine the engaging and energetic Darwin in his prime. As a youth he showed no particular aptitudes for academic pursuits, although he did have a passion for collecting (especially beetles), dogs, and hunting. Medicine was a natural choice for a career, given the traditions of the family (both his father, Robert, and his grandfather, Erasmus, were medical doctors), but his time at the University of Edinburgh was not productive, especially given his aversion to the operating theater, and he was soon home again.

In the end, Darwin went to Cambridge to pursue a degree in theology. His intent was to be ordained and serve as a priest in the Church of England. It was at Cambridge that his latent interest in Natural History came to full-flower under the influence of several energetic professors who taught numerous science courses. Darwin became enthusiastic about geology, spending time in the field with several of the major figures in this developing new science, but his favorite on the Cambridge faculty was Professor Henslow, who taught botany.

As Darwin was finishing his work at Cambridge, Captain FitzRoy of the H.M.S. Beagle contacted Henslow. The Beagle had been commissioned by the Admiralty to conduct a voyage around the world, with a special focus on mapping and geological exploration in South America. FitzRoy was looking for an individual who might be interested in doing much of the geological and other natural history studies and Henslow was his first choice. Unable to make the voyage (which was then estimated at three years), Henslow suggested the young Darwin as a suitable candidate and eventually all arrangements for the voyage were finally completed.

• The lack of a real imperative (was such a theory really needed?)
• insufficient time to accomplish significant change (given the supposed 6000 years of earth history, based on theological interpretations)
• lack of any real mechanism that might drive evolutionary change (the ideas of Lamarck having been thoroughly and properly rejected).

Charles Lyell, author of the Principles of Geology, which essentially founded the modern science of geology. Levin, 1996, The Earth Through Time.

Lyell was a synthesist and original thinker who did a masterful job of summarizing much of the preceding pioneer work in the science as well as providing new insights. His book (Darwin was to have later volumes shipped to him during the course of the voyage) was a marvelous practical manual in geological studies and interpretation. This was the primary reason why Henslow gave Darwin a copy, although he did caution the young man to avoid serious thought with respect to Lyell's "wilder" theories - especially with respect to the age of the earth!

In fact, if one took Lyell seriously, which Darwin came to do after discovering the utility of Lyell's approach when working with both rocks and fossil excavation in South America, one had to be persuaded that the earth was much, much older than suggested by theological studies. In effect, Lyell's book removed the impediment of time!

The second major impact on his thinking concerned patterns of bio-diversity. To someone who had been trained in the temperate zone, the bio-diversity of the tropics was awe-inspiring. This, coupled with the strange and often puzzling endemic species encountered on isolated islands and other remote places, raised real questions with respect to the "fixity" of species - a basic tenet of Creationism.

Several species of giant tortoise (land turtles) are endemic to the Galapagos Island group. The islands are semi-arid and not very hospitable, as indicated in the scenic background for this specimen. The bio-diversity of the tropics, coupled with the puzzle presented by endemic species, started Darwin thinking about the "species problem". Campbell, 1996, Biology.

One of the major myths about the voyage concerns the impact of the 13 species of endemic finches Darwin collected while the Beagle cruised the Galapagos Island group. Four of the species are illustrated below:

Beak adaptations of several of the 13 finch species on the Galapagos Islands. The birds are known as "Darwin's finches", in honor of the man who first collected them. Starr and Taggart, 1989, Biology - the Unity and Diversity of Life.

The fact is Darwin did not recognize that all of these birds were finches and they raised no particular questions in his mind, other than natural curiosity. The bird specimens, like much of what Darwin collected, were shipped back to England for study by specialists in different fields. Much later, while working on the studies that would lead to the Origin of Species, Darwin clearly recognized the significance of the birds that, by that time, had been named and classified.

The voyage was to end in 1837 and, on his return, Darwin started his famous notebooks on what he called "The Species Problem". Patterns of bio-diversity had convinced him of the need for a solution to the problem, while geology provided the needed dimension of time. Darwin's unique contribution in the years to follow would be the development of a comprehensive and acceptable mechanism - natural selection - that could drive evolutionary processes.
 

Darwin Resource Site includes access to the complete hypertext version (with illustrations) of the Voyage of the Beagle and the Origin of Species, plus a variety of other Darwin-related links. This link is provided for those who want to gain greater insight into Darwin and his writings and the information provided is not required reading.