I recently had the pleasure of attending a lecture by historian of science Dr. Michael Shermer, paleontologist and geologist Dr. Donald Prothero, and biologist Dr. Joel Smith. These men provided insights into the life of Darwin and how evolutionary theory, and the methods by which we study it, have changed since Darwin’s time. I would like to share a bit of my experience and what I learned at this event, but since I am far from a scientist, I must implore the reader to consider any errors herein to be my own misunderstanding (or poor note-taking) and not the errors of these great minds.
Dr. Prothero can speak about as quickly as he can think, and he managed to fit an enormous amount of information into his brief allotted time. Dr. Shermer later quipped that Prothero is the only man he knows “who can fit a three hour lecture into thirty minutes!” Dr. Prothero took us on a frenzied tour of the entire history of evolutionary theory, from Darwin to today. During Darwin’s life and the following years, evolution was widely accepted as fact in the scientific community, but acceptance of Darwin’s method by which it occurred, natural selection, was hard-won. Even after the importance of Mendel’s findings in the field of genetics was realized in the early 20th century, the majority of scientists still did not view natural selection as plausible. George Gaylord Simpson’s book, Tempo and Mode in Evolution, began to change this view by demonstrating a consistency between the facts of paleontology and those of natural selection and genetics. However, Simpson believed that genetics alone was sufficient to explain what was observed by paleontologists.
By the late 1950s, there was little controversy or dissent about the methods by which evolution occurred, but in science this is not a good thing; science gets better through being challenged. This challenge came in the 1970s, when the theory of punctuated equilibrium was brought to fruition, demonstrating the inaccuracy of the “Galapagos finch” idea that organisms are infinitely flexible in their ability to adapt, evolving in one gradual, smooth line. Rather, long periods of stability are observed, even during extreme environmental changes. In fact, there was close to no observable response to the largest climate change in the last 65 million years, the Oligocene cooling event. Darwin’s friend, Hugh Falconer, actually warned Darwin that stability of Ice Age Mammoths through glacial cycles was common. The majority of Pleistocene mammals display stasis. Yet, this does not mean that the concept of phyletic gradualism is entirely incorrect. Punctuated equilibrium is actually a form of gradualism, and when huge geological time scales are taken into consideration, the tiny incremental changes from one generation to the next become apparent.
According to Prothero, Neo-Darwinism, and the idea inferred by George Gaylord Simpson that genetics has made paleontology somewhat obsolete, still dominate in classrooms. To paraphrase the late Stephen Jay Gould, ‘A revolution has occurred, but the textbooks don’t show it!’ Neo-Darwinists don’t distinguish between microevolution and macroevolution, and geneticists working with fruit flies simply can’t take into account the massive time scales that paleontologists and geologists work with. When “species sorting” is considered to be on a different hierarchical level than individual natural selection, a much more accurate picture can be drawn.
Next up was Dr. Joel Smith, who gave us a peek into systems biology and some of the work he has been doing with genome sequencing, gene expression profiling, and perturbation assays. Systems biologists are able to graph the genes of an organism, knock out or “perturb” one individual gene, and observe the effect. In working with sea urchin embryos, they have been able to synthetically recreate evolutionary change. Sea urchins and sea stars share a common ancestor and at some point, sea stars ceased to develop larval skeletons, while sea urchins did not. By transplanting the regulatory sequences of a sea urchin’s genes into a sea star embryo, they have been able to cause the sea star to develop a larval skeleton. Dr. Smith believes that this method of experimentation may help us draw more general rules for how evolution takes place and help us make predictions about how evolution will occur in the future.
The delightful Dr. Shermer finished up the event, beginning by showing photos from his recent trips to Darwin’s stomping grounds in the Galapagos Islands and England, and the Creation Museum in Kentucky. He shared some of the “wisdom” he acquired at the Creation Museum, such as the real age of the earth (4004 B.C. – about the same time the Mesopotamians invented beer), the real reason we have viruses and diseases (The Fall), and the real reason T-Rex had such fearsome and sharp teeth (so that it could crack coconuts!)
In Shrewsbury, Shropshire, England, Dr. Shermer visited Darwin’s home and school, and he shared some of Darwin’s life story with us. Darwin’s mother died when he was eight years old and, since his father was very aloof, he was essentially raised by his sisters. Although his father wanted him to follow in his own profession, medicine, Darwin was distressed by the fact that, at that time, surgery was a bloody, screaming affair, without benefit of anesthesia. Darwin had a fairly liberal religious upbringing, and while studying at Christ’s College, Cambridge, he became engrossed with many of the then popular works of natural theology, which sought to unite nature with religion. Later in life, Darwin lamented on the “cruel works of nature,” and this observation of cruelty, in addition to the death of his young daughter, led him to disbelief. He adopted the label of “agnostic,” which was a term coined by his friend, Thomas Henry Huxley.
Although it is commonly believed that Darwin discovered the theory of evolution while he was in the Galapagos, he did not begin to put together these ideas until much later, in the years following his five year voyage on the HMS Beagle. In fact, rather than noting the differences in the various tortoises while there, Darwin ate these tortoises on his journey! At that time, it was commonly believed that all truth could be derived from merely thinking about it. Testing and observation were not the norm.
Darwin was a gentleman scholar, but he was also competitive. He had planned to postpone the release of On the Origin of Species until after his death, in part to protect the sensibilities of his evangelical Christian wife, but after he became aware that Alfred Russel Wallace had reached similar conclusions about natural selection, he decided to proceed with the announcement of his findings. His theory was given its first public exposure at the Linnean Society meeting of 1858, and its legacy has endured.
As many of you know, Darwin would have been 200 years old this month, and I can only imagine how awestruck he would be to see the journey his theory has taken. Happy Birthday, Darwin!
-old fossil. We prepared our children with the expectation that Mom and Dad would be “taking a very long time” reviewing the entire exhibit. And we did. The exhibit is incredible.
