It is hard to bring to mind any scientist who was as controversial and misunderstood as Charles Darwin, not only in his own time but even to the present day.
He was born on 12th February 1809 in Shrewsbury, in the north midlands of England. His father was a doctor, himself the son of Erasmus Darwin, who was an early advocate of evolution. His mother was the daughter of Josiah Wedgwood, the pottery owner and one of the fathers of the Industrial Revolution.
Charles's mother died when he was only eight, and he was brought up by his three older sisters. In later life he looked back fondly on his childhood, recalling that he was given plenty of freedom to take long walks through the countryside, collect all sorts of objects that he found on his wanderings, and generally amuse himself.
He was educated at Shrewsbury School, which he hated, partly because the curriculum was based on knowledge for which he saw no need, and science was not regarded as a fit subject for study.
In 1825 Charles was sent, with his brother, to Edinburgh University to study medicine, following in the footsteps of his father and grandfather. Charles was frankly disgusted by the study of anatomy, and recoiled from observing surgery carried out without anesthetic. His preference was for studying the natural history of the Edinburgh area, particularly the invertebrates of the Firth of Forth. He also attended lectures on chemistry and geology.
Charles had read his grandfather's works on evolution, and he found plenty of people in Edinburgh who also contended that there were developmental links between different members of the animal kingdom, such that they shared common organs that differed only in complexity. However, their explanations as to how these links came about, and what they signified, were far from clear.
He left Edinburgh without a degree in 1827 and his father sent him to Cambridge with a view to his taking holy orders, once he had acquired sufficient Greek to be admitted.
At Cambridge he again neglected the course of study he should have been pursuing, preferring to collect beetles in the Cambridgeshire fens and attend lectures on botany, particularly those of John Stevens Henslow, whom he came to greatly admire for his scientific approach to natural history.
Much to his own surprise, Charles achieved an excellent degree from Cambridge in 1831. He planned to go with friends to Tenerife for a month, and decided to take a short field course in geology as preparation. However, on his return he found a letter from Henslow that offered him a much more exciting project, namely a two-year round-the-world trip on a scientific mission, on which he would be expected to collect and observe anything that pertained to natural history in far-flung parts of the world.
HMS Beagle sailed from Devonport on 27 December 1831 and did not return for five years, rather than the intended two. The primary purpose of the voyage was to make geophysical and navigational measurements, although the presence of a missionary on board suggested that there were ulterior motives.
Although Darwin's chief interest was natural history, he also made many geological observations and collected specimens. He sometimes traveled overland, spent extensive periods ashore, and had many adventures. His geological work should not be ignored, because his growing conviction that geological events took place across immense intervals of time was very much part of his later evolutionary theories that required changes to take place over periods of millions of years. Also, as a geologist, he came across the fossil remains of species that were clearly long extinct, but which had a place in the chain of the development of life on planet Earth.
Darwin packed up many of his specimens and sent them back to Henslow in England, where they excited considerable interest. However, he made a few mistakes with his labeling of the crates, so that some of his most significant findings were not made until after he had returned to England and been able to study his finds at leisure.
This was the case with the part of the voyage that had the greatest significance of all, namely the short visit to the Galapagos Islands off the coast of Ecuador. The most important aspect of the natural history of the islands, which was extraordinary enough with its iguanas and giant tortoises, was that each island had slightly different varieties of certain species, including the finches. However, it was only after he was able to sort out the labeling errors that he could work out just how important these differences were.
When Darwin came home, landing at Falmouth on 2nd October 1836, all thoughts of a career in the Church had left him. He now had no plans other than to devote his life to the cause of science.
His specimens were examined by a whole range of specialist scientists, who were in a position to compare them with others that had been collected at other times and other places. For example, Richard Owen, a comparative anatomist, suggested that his South American fossils were extinct, giant forms of animals that currently existed in the region. This led to Darwin's realization that species became extinct but related species continued to exist. Another realization was that the Galapagos mockingbirds and finches were of different species on the different islands.
Darwin now spent a matter of years on working out what all this evidence pointed to, and the geological evidence was as much in his mind as the zoological. He had received a great deal of attention from the scientific community since his return, and been elected to membership of a number of influential organizations, including the Athenaeum Club and the Royal Society, and was aware that he had much to lose if he expressed views that were widely divergent from those currently in vogue. Above all, he was still greatly puzzled as to how species could originate so as to be as they appeared from the evidence he had accumulated.
In working towards a theory, certain principles gradually became clearer in Darwin's mind. One was that very small changes could have huge consequences over long periods of time. This was clear from his observation of the formation of coral reefs. He knew just how small a coral polyp was, and how many polyp lifetimes it must take to create the massive reefs that he had observed. He also became convinced that, in the matter of species creation, God had nothing to do with it. Species adapted to suit their environment, and if they could not do so, they became extinct. There was no room for divine intervention in this process, as the minute variations between individuals were, to him, clearly matters of chance.
As a young man, Darwin had mixed with farmers and animal breeders, so he was well aware of how characteristics could be bred into and out of animal flocks and herds, and how substantial changes could be made, over several generations, simply by selecting the individuals who were to breed.
Another brick in the wall of his theory was provided by the work of Thomas Malthus, who had looked at human populations and deduced that over-population led to events, such as wars and famines, that reduced their numbers to a sustainable level. If this was true of humanity, why did the principle not also apply to the animal kingdom?
Darwin knew that making such views public would not be wise. He therefore confined his thoughts to a series of secret notebooks. However, he did make his materialist views known to the woman he proposed marriage to. This was Emma Wedgwood, a first cousin on his mother's side, whom he married in 1838.
Charles started to suffer from ill health shortly after his marriage, and he was also keen to provide a suitable home for his young family. Using money borrowed from his father, he bought Down House, in Kent, where he was to live for the rest of his life. Here he became something of a recluse, and a pillar of local society, only traveling to London when absolutely necessary. His family grew in number, with his wife bearing ten children in all, although three of them died young. He also suffered from increasing ill-health, and believed that he did not have long to live.
He now completed his theory, on 231 handwritten sheets, but gave instructions that it was not to be published in his lifetime. He turned his attention instead to minor projects, including a study of barnacles. This confirmed his belief in transmutation, that one species could evolve to become another, which was central to his theory but which was bound to create a storm of controversy once published; for if a crab-like ancestor could evolve into a barnacle, then apes could have evolved into humans, a conclusion that ran counter to all the teachings of the Church as well as of most of the scientific community.
In May 1856, after conducting a series of experiments to test whether aspects of the theory could work in practice, Darwin began to write what would eventually become "The Origin of Species", with a view to making the book accessible to the general public. He also became aware of the parallel work being done by Alfred Russel Wallace who, from different evidence, had reached much the same conclusions regarding natural selection. However, he had no wish to compete with Wallace, and both were happy to announce their conclusions at the same time. Darwin and Wallace never became close, but they greatly respected each other's work and at no stage there was there any animosity between them.
The book was published in April 1859 and received considerable support in the scientific community, and also within the liberal wing of the Anglican Church, because Darwin had not removed God from the picture completely. However, many people drew the conclusion that Darwin had not stated explicitly, namely that man was descended from the apes, and the debate was polarized by some of Darwin's disciples, notably Thomas Huxley in his famous debate with Bishop Wilberforce in June 1860.
Despite severe bouts of ill health, Darwin continued to defend his thesis and to tackle some of the weak points of "The Origin of Species". One problem was that of how inheritance operated between generations, which would only be solved many years later with the discovery of DNA. Later editions introduced the phrase "the survival of the fittest" in addition to "natural selection", as an explanation of how variations in individual members of a species could lead some to survive and breed while others died out.
In 1871 Darwin published "The Descent of Man" as a sequel to "The Origin of Species". This dealt with the process of sexual selection as well as tackling the difficult issue of man's place in the evolutionary chain. The book caused less initial outcry than "Origin", despite Darwin's setting out of the family tree linking human with ape-like ancestors. However, many contemporaries were shocked by his depiction of early humans as being covered in hair, having tails, and living in trees. This did not accord with the common view of how Adam and Eve would have appeared.
He turned to botany as his chief subject of study, as he regarded plants as being just as important as animals in explaining the processes of natural selection. For the last 20 years of his life he published extensively in this field, making the point that plants are as they are purely as adaptations to the conditions in which they grow, and in order to maximize their chances of reproduction.
He was also anxious to show that cross-pollination between different varieties of plants led to stronger growth, and therefore an increased chance of survival. He may well have considered this from the aspect of human inbreeding, perhaps wondering if his own marriage to a first cousin was responsible for the illnesses of his children.
In his last years he was well respected by most of the scientific community, and certainly by the more liberal wing of Victorian public opinion, although his religious views, which tended towards agnosticism rather than outright atheism, would always alienate him from a substantial section of society. He also found that his general health improved as he got older.
He died on 19th April 1882, aged 73, expecting to be buried in the local churchyard. However, a campaign by the scientific community, and the press, ensured his burial in Westminster Abbey. Darwinism clearly had not shocked his contemporaries to the extent that later generations might have imagined.
After Darwin's death, his ideas evolved into something that Darwin would not have recognized, and the great debate about man's place in the animal kingdom has been raging ever since. Later theorists took the parts of Darwin's theories that suited their particular interests and used them to justify opinions that Darwin would have abhorred. Worst among these must surely have been the Nazis, who seized on Darwin's "Origin" subtitle, "the preservation of favored races in the struggle for life" as a justification for genocide.
It should be remembered that Darwin constructed his theory from the evidence he had to hand. Had he known about plate tectonics, in regards to geology, or DNA, as the mechanism of genetics, he would surely have created a more complete theory. Whether it would ever have satisfied the religious fundamentalists whose science was based on texts written long before the development of scientific method, is another matter altogether.