First Parish Church - Darwin's Revolutionary Idea

Charles Darwin — His Revolutionary Idea

Nancy Lewis
Former science teacher, Curtis Middle School

Presented in the panel
Galileo, Darwin, and God: Anniversary Retrospectives
First Parish Church in Weston
December 6, 2009

My discussion on Charles Darwin will include three sections. The first will be a short biographical sketch including some of the scholars who influenced him. Then I will describe his theory and give some examples. Finally I will mention some of the controversies his theory has elicited.

As I have said I will begin with a brief section on his life.

Charles Darwin was born on February 12, 1809 (same exact date as Abraham Lincoln). His parents were wealthy and he was afforded many privileges including a fine education. First he tried medicine, then religion, but his real passion was natural history . At Cambridge University he met John Henslow, a natural history professor, and attended many of his lectures. It was Henslow who recommended Darwin for the Beagle. Darwin was hired on to the Beagle as a naturalist and it was Henslow who received Darwin's collections from his trip. Reluctantly his father agreed to the one year voyage which took five years and went around the world. Darwin was prone to seasickness and went ashore as often as possible. He collected many specimens which became the basis of his life's research. His experience in the Galapagos Islands was particularly meaningful. He collected many birds, all different he thought. However, when he returned to England bird experts identified them all as finch varieties.

On return to England,he moved with his new wife to Down House, an estate south of London. There he began his research. Notes he made in 1837 suggesting he was beginning his thoughts on evolutionary theory as well as two papers in 1842 and 1844 gave him proprietary rights to the theory. None of these documents were published and were known to only a few of his friends.

Darwin was influenced by many scholars. His own grandfather, Erasmus Darwin, had written a book, Zoomania, in 1812. It theorized that all life was derived from one filament. Linnaeus who classified all plants and animals implied by his work that there was variation within species, an idea which contradicted the prevailing thoughts. Malthus had published a population theory which showed that the power of population growth of animals would ultimately outstrip the food supply. Darwin's friend, Lyell, a geologist said that if you wanted to know the past you had just to study the present. Also, Lamarck came up with a possible mechanism for passing on characteristics. He said that if you needed a trait you would acquire it and that trait would be passed on to the next generation.

This next section will discuss Darwin's evolutionary theory and cite some examples.

For twenty five years, Darwin studied his specimens and began to mold his theory. He agonized about the impact his ideas would have. He was not completely finished with his writing when, in 1858, he received a letter from Alfred Russell Wallace, another English scientist working in the South Pacific collecting specimens for a museum. He outlined a very similar theory to Darwin's. Darwin's initial reaction was to let Wallace have the credit, but friends convinced him to go jointly to the Linnean society to present the idea. In fact, Darwin claimed he was too ill and his friends presented for him. Then in 1859, twenty five years after his return on the Beagle he published, Origin of Species, a detailed volume exposing his theory.

The essential points of the theory are summarized with three statements and two conclusions.

Any species has the power to recreate infinitely.
In fact, the numbers within a species remain fairly constant.
Therefore there is a struggle for existence.
There is variation within a species.
Therefore those best able to adapt will live longer and produce more of their kind –“survival of the fittest”.

The animals of the Galapagos provide some excellent examples of this process. The islands are volcanic and were and are being created when the Pacific plate rotates over a hot spot. They are 600 miles off the coast of South America so any of the original life forms there had to arrive by swimming, floating or flying. Iguana were originally exclusive to the land. Once they got to the island, they were confronted by a limited food supply. As that food supply diminished, some began to go into the water for food. Now we have two distinct species of iguanas. They adapted and survived to produce more of their own kind.

The finch is of particular interest – then and now. Darwin's finches were only slightly different from one another. He began to realize that the original finches had offspring some of which had flown to different islands and adapted to the unique food supply on that island. There is even one finch which uses the spine of the cactus to dig out insects from a log.

The book, The Beak of the Finch, documents a research project done by the Grants working out of Princeton. They have spent years living and studying the beaks of the finches. Their island, Daphne Major, is tiny. They have measured the beaks of finches in different weather conditions. They discovered that in drought years the beaks get shorter (and tougher) to be able to eat the harder seeds that have fallen to the ground. Conversely, during wet periods the beaks get longer to deal with the softer seeds growing on the cactus. Again the conditions forced the finch to adapt and those that lived longer produced more of their own kind – “survival of the fittest”.

To conclude, I will discuss some of the resistance Darwin faced and evolution is still fighting.

Darwin’s theory certainly caused a maelstrom of controversy. Darwin himself did not appear publicly but was represented by his friends Hooker and Thomas Huxley. Huxley once quipped that he would rather be descended from an ape than a man who misused his gifts. The most famous debate took place with Bishop Wilberforce. Darwin was even shown in political cartoons looking like an ape with a tail. Darwin said that being a theist and an evolutionist was impossible. He didn't think of himself as an atheist in that he believed in God. He probably was more an agnostic. There was certain background information Darwin was missing which made it difficult for him to convince people. He needed extended time for his natural selection to become effective. A large number of people then went along with Bishop Usher who said that the earth was only 6000 years old. A couple new theories extended that to two million years, still too short a time. The theory of genetics which could explain the mechanism for mutations to occur and endure was written. However, Gregor Mendel lived in Austria (still feudalistic) and his experimental data was not widely disseminated. Good examples locally would have been a little more convincing, but most didn’t know about the moth who evolved from white to gray to blend in with the sooty trees caused by increased factories in the Industrial Revolution.

Today even with better understanding and much more research evolution is still a controversial subject. Creationism, aka Intelligent Design is favored by many especially those in conservative religions. Evolution is not a required subject in many states and others insist that creationism be mentioned also. The chairman of the State Board of Education in Texas is an ardent creationist who believes the earth is only a few thousand years old. He and his committee will decide whether evolution will be taught. Southern states particularly show the greatest resistance.

Will there be a time when the theory comes to be proved and accepted? The theory was published 150 years ago and there is continual dissent. Really evolution is still evolving.