THE BEECHMONT CREST GUIDE TO BIOLOGY
The Story of Darwin
Centuries have passed since the work of Galileo was a source of public debate. Among the historical scientists, Darwin is the only one whose theories continue to ignite controversy.
Charles Darwin was born in Britain in 1809. In Darwin’s time, people believed that the species had been created in their current forms by a Divine Creator. Life forms were thought to be immutable. The flora and fauna inhabiting the earth looked as they always did. People in the early 19th century also held that the earth was only a few thousand years old. Our modern concepts of an earth formed 4.5 billion years ago would have been brushed aside like so much science fiction.
As a young man, Darwin believed the conventional wisdom of his day. However, his opinions would change as the result of now famous journey that he took in his early twenties. Darwin was a student at Cambridge University, and one of his professors recommended him as a participant on a five-year mapping expedition around the coastline of South America.
While in South America, Darwin observed the local flora and fauna, which must have seemed almost extraterrestrial compared to the wildlife he was accustomed to in England. The giant tortoises in the Galapagos Islands caught his attention in particular, and spurred his reflections about the development of individual species. Darwin noticed that there were physical variations between the tortoises on different islands. In fact, local fishermen were able to identify which island a tortoise came from just by examining its shell. Although the tortoises were clearly related, they had obviously developed in different ways after being separated to different island communities.
While traveling throughout the islands off the South American coastline, Darwin noticed a general similarity between the wildlife on the island and the nearby mainland. However, according to the “immutable species” view of nature, the wildlife on the islands should also resemble the plants and creatures found in similar island climates off the coast of Africa. This suggested to Darwin that living things had not simply been dropped in place at a single creation event at the beginning of time.
On the South American mainland, Darwin observed the fossil remains of the glyptodont, a prehistoric version of the armadillo. The two animals--one living, one extinct--seemed to be related. Could the glyptodont be the ancestor of the armadillo?
Darwin returned to England after completing his five-year voyage. Now twenty-seven, he began a decade of study, research, and publishing. Among his accomplishments during this period were a book on South American geology, and an extensive study of barnacles. He also began work on a manuscript that would eventually be published under the title The Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life.
In his manuscript, Darwin outlined the theories of natural selection and evolution. The population growth principles proposed by Malthus in Essay on the Principle of Population (1798) became a key element of Darwin’s work. Malthus had pointed out that the population of plants and animals has the potential to increase geometrically. (This had implications for human society, since people are only able to make arithmetical increases in their food production capabilities.) Malthus predicted that without outside forces to check population growth (limitations on resources, predators, etc.) any single plant or animal species could reproduce until it covered the earth within a short period of time.
This realization made Darwin think more about the interaction between life forms and the forces that trim their populations. What factors allow some members of a species to survive while others perish? Darwin concluded that members of a species who were most well adapted to meet the challenges of the environment would survive. This is the concept of natural selection---often called the “survival of the fittest.”
Darwin’s ideas regarding evolution were based on his observations in South America, as well as the artificial selection techniques that he had seen practiced in England. Farmers had discovered that animals could be selectively bred to obtain a population with specific traits. If this could occur with animals in captivity, Darwin reasoned, it could also occur with animals in nature.
Darwin completed a preliminary draft of The Origin of Species in 1842. He then tucked it away in a drawer for sixteen years and turned his attention to other projects. No one is sure why Darwin delayed the publication of his famous book about evolution and natural selection for so long. It appears that he didn’t revise the manuscript extensively during the sixteen-year waiting period. Many historians believe that he was hesitant to publish the document for fear of the controversy that it would create.
It was actually another naturalist who prompted Darwin to submit The Origin of Species for publication. Fellow Briton Alfred Russell Wallace, who had been working in Malaysia, contacted Darwin in 1858 about similar research that he had completed. Darwin then arranged for the two of them to present their findings together at a seminar in London. Darwin’s book was published one year later, in 1859.
Despite the controversy generated by Darwin’s work among religious groups, it should be noted that Darwin never refuted the notion of a Divine Creator. He merely challenged the literalist interpretation that all life forms were created in one fell swoop, with no subsequent changes.