After this post, we’ll gather on Wednesday’s and Saturdays for new posts in this series.
Charles Darwin never knew about DNA, or genes, or genetics. DNA and protein, as well as the debate about which was the genetic material came after Darwin. The definitive experiment showing DNA as the genetic material was performed in 1952 by Hershey and Chase, a mere eight years before I was born. No, Darwin didn’t have any of the knowledge that contaminates our perspective on him. We can be so smug and self-assured when we look back on Darwin and his contemporaries.
To do this conversation justice, we must enter into Darwin’s world as it was, and see that world through his eyes.
Young Darwin was actually a medical student who became taken with the field of natural history. It was a dynamic age in naturalism and, contrary to popular belief, Darwin was NOT the first to propose that life evolved. There were actually many before him, many who backed down under threats of excommunication from civil society and some from their churches. The most prominent proponent who advanced a scientific hypothesis of evolution was Jean-Baptiste Pierre Antoine de Monet, Chevalier de la Marck. We know him today simply as, Lamarck.
Lamarck lived from 1744-1729, dying two years before twenty-two year-old Charles Darwin would set sail on his famous five-year voyage aboard the HMS Beagle. Lamarck proposed that life evolved by organisms developing adaptations to their environment and then passing them on to their offspring. Today he is remembered in most biology classes as the fool who got it wrong. In reality, Lamarck was a brilliant invertebrate biologist who coined both the terms invertebrate and biology. Lamarck established most of the taxonomic trees for invertebrates, and is widely regarded in the field as one of the fathers of the field. Back to Darwin.
As a young and budding naturalist, Darwin was afforded the opportunity to sail aboard the HMS Beagle in 1831 (Recall that Darwin would not publish Origin of the Species until 1859). It was a time of great exploration and scientific documentation of the flora and fauna of distant lands, of geology and anthropology. The discovery of fossils and the observations of sedimentary rock containing those fossils was a hot topic. It was observed that sediments form at certain rates, and that sedimentary layers of rock could not have formed in the time since Sunday, 23 October 4004 BC, which was Bishop Usher’s biblical calculation of when the world was created.
The concept of geologic time outside of Bishop Usher’s frame was pointing toward a planet that was hundreds of millions of years old, at the least. Fossil evidence, it was further noted, indicated that the deepest sedimentary layers had the most primitive looking organisms, while organisms generally increased in size and complexity in the newer, more surface sedimentary layers.
Darwin carried with him on the Beagle Volume 1 of Principles of Geology, by the foremost geologist of the day, Charles Lyell. Darwin received Volume 2 when he reached South America. Lyell had Darwin do investigations for him, and it is fair to say that Darwin came away much more convinced of evolution based on the geology than did Lyell. In fact, Lyell disagreed with Darwin, and only gave grudging and tepid acceptance of modification by natural selection after Origin of the Species was published. Lyell would write in his 1863 book, Geological Evidences of the Antiquity of Man that it remained a profound mystery how man bridged the evolutionary divide between himself and the beasts. So not all scientists were of one accord in Darwin’s day, not even his great friend Lyell.
Regarding Darwin’s famous voyage on HMS Beagle, I’m rereading it for the first time in years. However, there is an excellent site with an interactive map of Darwin’s voyage that nicely summarizes each phase of the journey.
It’s worth doing a little reading at that site, as we’ll begin to systematize Darwin’s findings in our next post.