OUR UNDERSTANDING OF EVOLUTION CONTINUES TO EVOLVE

 

On a recent summer evening, my wife was busy page-turning our copy of the weekly New Yorker magazine. Like many of us, the cartoons were the main attraction with occasional stops at articles that grabbed her attention.

She was reading a piece reprinted and reviewed to commemorate the 1925 Scopes trial, first written one hundred years ago by the magazine’s reporter who was in attendance. This well-publicized Tennessee criminal trial focused on the illegality of teaching evolution in public schools.

As we discussed the article, it suddenly occurred to me how divisive the subject of evolution has been in the American cultural wars. I also learned that new scientific studies highlight how our understanding of evolution continues to “evolve” as new discoveries are made.

Charles Darwin and Alfred Russel Wallace were both English naturalists who independently developed the theory of evolution. Darwin’s publication of The Origin of Species in 1859 turned all of biology and theology upside down. Previously, geologists and paleontologists made a compelling case that life had been on Earth for millions of years, that life had changed over time, and that many species had become extinct. It was the genius of both Darwin and Wallace to show how all this evidence favored the evolution of a species from a common ancestor. They offered a plausible mechanism by which life might evolve. This process Darwin called natural selection.

Darwin and Wallace each deduced that if a species had some trait that helped it to withstand the elements or to reproduce more successfully, it might leave more and stronger offspring behind. These traits seemed to become more common in subsequent generations.

According to the Berkley University, History of Evolutionary Thought, The Origin of Species was one of the most influential scientific books of all time. The authors go on to explain, “Yet it took years for its full argument to take hold. Within a few decades, most scientists accepted that evolution and the descent of species from common ancestors were real. But natural selection had a harder time finding acceptance. In the late 1800s many scientists who called themselves Darwinists actually preferred different explanations for the way life changed over time. Not until the discovery of genes and mutations in the twentieth century was natural selection not just attractive as an explanation, but unavoidable.”

Theologians initially believed that Darwin’s theories were a serious challenge to traditional religious understanding of the creation of the world. According to the Pew Research Report, in 1925, when the Scopes trial captured the attention of the nation, there was no public polling on how many Americans believed in evolution. However, Pew points out that, “by the early 1920s evolution had become one of the most important wedge issues in the cultural divide because the debate had taken on a pedagogical dimension. Students throughout the nation, now studied Darwin’s ideas in public school biology classes.”

In 1925, the Tennessee Butler Act prohibited the teaching of evolution in public schools. The A.C.L.U. published a newspaper ad offering to defend anyone who would test the constitutionality of this new state law. A substitute high-school teacher, John Scopes, agreed to become the defendant in order to stage a criminal case. Clarence Darrow represented the defendant and William Jennings Bryant, the state of Tennessee. Scopes was convicted and ordered to pay $100 dollars. (Bryant died five days after the verdict.) All appeals failed. The Tennessee Butler Act prohibiting the teaching of evolution was not repealed until May 17, 1967.

Today, according to Pew Research, roughly eight-in-ten U.S. adults (81%) believe humans have evolved over time. However, around four in ten white evangelical Protestants continue to maintain that humans have always existed in their present form.

Wikipedia informs us, “As of 2024, all fifty U.S. states and the District of Columbia include the teaching of evolution in their public-school science standards, while none teach intelligent design. Creationism can be discussed in non-science classes, such as philosophy or comparative religion.”

Now that the theory of evolution has been widely accepted, in what respects does it continue to evolve? The Evolution of Imperfection by Laurence Hurst, a professor of evolutionary genetics at the University of Bath, provides some fascinating answers. Hurst offers solid science that evolution does not always work for the good of the species. Evolution is not designed to correct all of our faults and imperfections.

Some examples include our inability to synthesize vitamin C because our ancient ancestors had an overabundance of fruit. High blood pressure during pregnancy helps the fetus absorb nutrients but is dangerous to the pregnant mother.

The relatively small population of humans enhances the influence of chance in evolutionary changes. This leads to both the accumulation of unnecessary DNA and unhelpful mutations. Evolution is not a process of good or bad. It is a process of trial and error that does not always produce the best result in modern man.

For those that are seeking a deep dive into the science, Hurst does an excellent job of reviewing modern genomics, the study of an organism’s DNA. He explains how mutations happen, why they persist, and why humans hold a large reservoir of troublesome genetic errors.

Evolution is a process that is always rolling the dice as our species advances.  Humankind did not start out biologically perfect and is far from it now.