Charles Darwin and the Theory of Evolution
These are the words of the famous English naturalist Charles Robert Darwin (1809-1882). Charles Darwin’s research lead to the now widely accepted scientific theory about natural selection in the process of evolution.
Charles Darwin was born in Shrewsbury, England into a wealthy and well-connected family. Following his father’s wishes, Darwin attended Edinburgh University with the intention of becoming a physician. He was not interested in this profession and dropped out. However, during this time he had been interested in his studies of natural history. He then transferred to Cambridge and took up a Bachelor of Arts degree with the intention of becoming an Anglican minister.
In 1831, because of his strong interest in natural history (more so than religion), Darwin joined a five-year scientific expedition on the survey ship HMS Beagle acting as an unpaid naturalist and companion to the wealthy captain of the ship. It was on this voyage where he read Lyell’s Principles of Geology which proposed that the fossils found in rocks were actually evidence of animals that had lived many centuries ago. This provoked Darwin to think about these concepts as he experienced the rich variety of animal life and the many different geological features during his voyage. It was when visiting the Galapagos Islands that his first concepts of the principles of evolution began. He noticed that each island had its own species of finch which were closely related but differed in important ways. For example, finches with longer beaks were found in environments where the nectar was deeply embedded in flowers, finches with sharper beaks were found in environments where seeds were the more abundant food supply. Darwin began to connect this to theories of natural selection.
Darwin continued exploring these theories when he returned to England in 1836. He began working on an early theory of evolution –the change in inherited traits in a population of organisms which is passed from one generation to the next. He drew significantly on the work of Thomas Malthus. Malthus had studied the way in which human population growth depended on the amount of food suitability of food available. Prior to the works of Darwin, the theory of evolution had been explored, but the enormous amount of data that Darwin had collected enabled him to produce volumes of evidence, unlike any scientist before him.
Charles Darwin’s studies contradicted the fundamental principles of Christianity and lead him to question his own personal beliefs. Already, any theories of evolution had caused significant controversy for example, in 1844, Robert Chamber’s anonymous publication, Vestige of the Natural History of Creation, caused great upheaval in the scientific and religious community. Because of such events, Charles was reluctant to present his findings and so they remained secret for some time.
It was only in 1859, when Darwin learnt about the research of Alfred Russell Wallace, that he decided to publish his findings which were based on 20 years work. Wallace was a young naturalist who had begun forming his own theory of natural selection very similar to that of Charles Darwin
The ideas had been circulated amongst the science world, although not fully accepted, his theories were met with less argument that previous scientists with these theories. During the next twelve years, he refined his theory and applied this to the evolution of humans. He published a book entitled ‘The Descent of Man’ in 1871. By this time evolution was becoming a common concept and more widely accepted than ever.
Darwin's Theory of Evolution is as follows:
Variation: There is variation in every population.
Competition: Organisms compete for limited resources. Offspring: Organisms produce more offspring than can survive.
Genetics: Organisms pass genetic traits on to their offspring.
Natural Selection: Those organisms with the most beneficial traits are more likely to survive and reproduce
An example of natural selection is that of the peppered moth which was studied during the Industrial Revolution. Before the 1800s, the majority of peppered moth were light coloured and dark coloured moths were rare. During the Industrial revolution, waste from factories darkened tree trunks. The light coloured moth became rare and the dark coloured moth became very common. This change occurred because the birds which prey on the moth preyed on the least camouflaged ones. Because of their higher chance of survival, the dark traits of the dark moth were then able to be passed through to their offspring making the dark moths more common.
When Charles Darwin first proposed his theory, limited scientific knowledge was used to evaluate whether or not it should be accepted. One of the prominent foundations of evolution is the length of time needed for the natural selection process to occur. Instead of scientific knowledge, biblical chronology was used to calculate the age of the earth. The evaluation of Darwin’s theory was largely influenced by early biblical theories rather than scientific knowledge. For example, in 1650, Archbishop Ussher from Ireland insisted that the earth was created in 4004 B.C. This figure became widely known and accepted for a long time and opposed Darwin’s theory. Many naturalists also believed that modern creatures were far too complex to have evolved naturally and needed an intelligent creator.
Advances in scientific understanding often rely on developments in technology. Firstly, Darwin’s theory of evolution was assisted by advances in sea transportation. The HMS Beagle was built specifically for long distance travel to enable mapping to be undertaken. This meant that Darwin was able to collect data from many different and varied parts of the world, unlike earlier evolutionists. Also, improved magnification methods enabled Darwin to view and analyse species in more detail. In 1846, William Thomson, a well-respected British scientist, scientifically calculated that earth is roughly 20- 400 million years old based on the rate of cooling since it first formed. (Although this was a much greater figure than Bishop Ussher’s biblical estimate, it did not directly support Darwin’s findings.) Since presenting his findings, the discovery of radioactivity gave an increased understanding about the age of earth and this provided the proof that Darwin needed to show that there was enough time for the evolutionary process to occur. Another development was the understanding of the genes in 1900. This provided evidence that traits were through genes. In 1967, Darwin’s theories of human evolution were further supported by advances in DNA research. Scientists found significant similarities in the DNA of humans and apes. Furthermore, in 1990, the ability to DNA code lead to stronger evidence provided at molecular level.
Darwin’s theory of evolution has impacted significantly on modern society. Without it, modern biology would not exist. The scientific understandings of genetics, physiology and ecology are all connected and explained through his theories. It continues to form the basis of further scientific research regarding genetic modification and environmental sustainability. The evolution theory has challenged ancient religious views and it is still a much debated topic today. In addition, Darwin’s theories have been used to justify and gain support for racist views and has sometimes even supported war between nations. For example, Hitler’s views of race supremacy involved the elimination of ‘lower races’ by the higher civilized races.
Humans continue to piece together the history of earth in order to explain our existence and help the survival of our species. Fossil findings continue to be pounced upon by scientists keen to fill in yet another puzzle piece. Charles Darwin’s theory of Evolution is still very much a part of our lives today.