Charles Darwin, "Of the Origins of Species 1859"

The Origin of Species

Darwin turned wholeheartedly to the problem of evolution. Ever since his Beagle trip he had been convinced that the difference between what naturalists called 'varieties' and what they called 'species' was much less significant than previously thought. If pigeon breeders could create varieties as different as pouters, runts, and fantails, what would prevent nature from doing the same? And, given millions of years, wasn't it possible that a pigeon could be turned into something so radically different we would no longer be willing to call it a pigeon-or even a bird? Darwin was not the first to have these kinds of thoughts. Seventy years before, his grandfather, Erasmus, had devoted a whole section of his book Zoonomia to the issue of evolution. In 1844, Robert Chambers anonymously published his controversial book, The Vestiges of the Natural History of Creation, a sweeping history of the cosmos that came down strongly on the side of evolution, largely on the evidence of fossils (the 'vestiges' of creation). The book was flawed, but popular, and it brought the idea of evolution into the public eye. The opposition to evolution was still strong, but it included among its number a wide range of opinions, from those who thought that all species had been created at the beginning of the world in the same form as they now had, to those who thought that new species were being continuously created to fill new environmental niches, to those who thought that variation within species was within Nature's power but the creation of new species remained in God's hands. Darwin had two things to contribute to this debate: a wealth of observations on adaptation, and, more importantly, a theory that could explain how new adaptations arose without the guiding hand of a divine Creator. His observations were gained by his own experience on the Beagle, his eight painstaking years of work on barnacles, and the advice and expertise of friends like Hooker. His theory was his own creation. Darwin solved the problem of evolution by pointing to a mechanism that depended on nothing but variation and chance: natural selection. Many more individuals were born than could be supported by the environment, which meant that some had to die. Which ones died? Obviously, those that were least well adapted to the environment. Given that there is variation in the population, and that that variation is heritable (i.e. can be passed from one generation to the next), it was clear that the most useful adaptations would be preserved. If enough of those adaptations were accumulated, a new species could arise. Although this sketch of the theory was already in place in Darwin's notes, in 1854 he was still struggling with a few pieces that he had yet to make sense of. One had to do with the population of islands like the Galapagos. According to his theory, animals and plants had arrived on the islands millions of years before and had slowly adapted to fit the unique environments on each island. But how had they gotten there in the first place? He was unwilling to accept the possibility that these volcanic islands had once been closer to the mainland of South America. Instead, he tried to prove that seeds and even eggs might have been transported on ocean currents from the mainland. He conducted experiments: soaking seeds in salt water for weeks to see if they would still germinate (most did) and figuring out which seeds would float (most didn't). The second puzzle piece was why there was such a great diversity of life in the world. If every species was continuously adapting to fit the environment as best it could, why didn't all species converge to the same form? Shouldn't there be some 'best species' that would dominate all others? Darwin solved this problem by drawing an analogy with modern industry. It was not true that there was a single 'best job' in any task. In fact, production got more efficient the more specialized each worker became. The same held true in the natural world: species specialized so that they could capitalize on particular aspects of the environment. In fact, a species that was failing in the competition in one particular environmental niche could become startlingly successful if it simply shifted niches so that it was no longer in head-to-head competition similar species. To shore up his understanding of variation under artificial selection-the kind of selection that had produced pets and domestic farm animals-Darwin started to learn all he could about pigeons. Breeding pigeons was a pastime that few aristocrats threw themselves into, but Darwin eagerly built a shed in the yard behind Down House. He started making trips into London to speak to the professionals, downing beers with them while they boasted about how they could see differences of 1/16th of an inch between two pigeon's beaks. Darwin studied not only living, breeding pigeons, but also dead ones; for a while, his workshop became a shop of horrors as he killed and 'skeletonized' pigeons of all varieties and ages, not to mention the occasional rabbit or chicken, studying the sometimes striking differences in structure between different varieties. Meanwhile, Darwin was testing out his theory of evolution on friends like Hooker and zoologist Thomas Henry Huxley. No one was entirely convinced yet, but some progress was being made. When Lyell, the geologist whose Principles of Geology had so inspired Darwin while on the Beagle, found out about Darwin's theory, he urged him to publish it as soon as possible, if only to ensure that he would not be scooped. Darwin demurred: he was much more interested in producing a watertight case for evolution by natural selection than in gaining credit for a theory that could be easily dismissed. Nonetheless he started working on a manuscript in May of 1856. It started as a sketch, but it quickly became obvious that, when completed, it would rival Lyell's Principles in length, and would probably have to be published in multiple volumes. In November of 1856, Charles Waring Darwin was born, the first child Emma had given birth to in five years. It was soon clear that he was severely retarded. He died a year and a half later when a scarlet fever epidemic raged through Down. By April 1857, all of Darwin's hard work had made his chronic illness return in full force. He took time off in April for more hydropathy, which he was beginning to think worked only because it relaxed him and forced his mind of work. Nevertheless, he was happy to do anything that could make the pain, nausea, and weakness subside. He worked productively for another year, but on June 18, 1858, he received a letter which instantly set him back: it was a short manuscript from Alfred Russell Wallace, a younger naturalist with whom Darwin had been in contact off and on for several years, and, at first reading, it looked like a carbon copy of Darwin's own theory. Darwin felt threatened. After Darwin had worked twenty years and waited for the right moment to publish, a young naturalist had come up with the same ideas. He wrote to Lyell for advice. Should he do the honorable thing, sending Wallace's article to the appropriate scientific society and continue to work on his own full-length volume? Or should he try, somehow, to hold onto his claim for having come up with evolution first? Darwin was torn. In the end, Hooker and Lyell decided that Wallace's paper should be presented before the Linnean Society, but Darwin should also contribute a sketch of his own theory. The joint presentation was made on July 1, 1858, with neither Darwin nor Wallace in attendance. Everyone listened politely, but there was neither the kind of outrage that Darwin had feared nor the approval that he had hoped for. Fortunately, Wallace turned out to be happy with the joint presentation; he knew that Darwin had been working on species for years and felt honored to have his work presented alongside Darwin's in front of a prestigious society. Newly galvanized by the fact that Wallace was nipping at his heels, Darwin threw himself into writing an abstract of his longer manuscript for publication. The abstract covered the same material as the longer manuscript Darwin had started in 1856, but it was pared down to clear, concise prose that stated the basic argument and presented the crucial pieces of evidence in support of it. He argued that species were not created, but rather evolved. He said that the mechanism in charge of directing evolution was natural selection. The first printing of the abstract was put on sale in 1859 under the title On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life. It sold out on the first day.

The Voyage of the Beagle, Part I

The offer of a position on the Beagle, which Charles received on August 30, 1831, came through his advisor, Henslow, at Cambridge. Henslow himself had been invited to be the naturalist for the ship, but had turned down the opportunity. The voyage had been commissioned by the government to map the coast of South America and was being captained by Robert FitzRoy, a 26-year-old gentleman who had led a ship to South America the year before. FitzRoy was eager to have the companionship of someone who, unlike the sailors and officers of the ship, was of his social class. A gentleman naturalist would fit the bill perfectly, providing companionship while increasing the usefulness and prestige of the voyage. Most well-established naturalists, like Henslow, had proven to be busy or disinclined, so the job had fallen to the promising but inexperienced Charles Darwin. Unfortunately, there was a hurdle to be crossed before Charles could sign on. He needed his father's blessing. Robert Darwin, however, had had enough of Charles's indolence. To Robert, it looked the attempt to make Charles into a respectable clergyman was about to fail as quickly as had his attempt to make him a physician. In his eyes, the voyage was nothing but a dangerous and unprofitable adventure that would do hurt Charles's chances for a solid career. Furthermore it looked suspicious to Robert that other, better-known naturalists had turned down the opportunity; there must be something wrong, he argued, with the ship or its captain. With a heavy heart, Charles rode to Maer to talk to his uncle Josiah. Josiah agreed with Charles that this was a once-in-a-lifetime opportunity; there was certainly no reason to think that the voyage would interfere with his career when he returned. In the meantime, it would provide an unparalleled opportunity to see the world and maybe even do some science in the process. He wrote a letter to Robert and sent it off immediately, enumerating the reasons why the voyage would be good for Charles. Charles returned to The Mount to find that Robert had been convinced. If Josiah was in support of the trip, Robert could hardly remain against it. Overjoyed, Charles began to prepare frantically for the voyage. The ship was scheduled to depart in a couple of weeks. But as he prepared, he received a shattering note: it turned out that there had been a miscommunication and FitzRoy had already promised the position to a friend. Charles would get the position only if the friend refused. Despite this setback he rushed to London to meet FitzRoy for an interview. FitzRoy seemed temperamental, but they got along reasonably well, and in the end FitzRoy's friend declined. Charles was given the position. He also found out that the trip was more likely to last three years than two, and that he would have to pay his own way. Having secured the position, Charles made a last farewell trip to visit Woodhouse, where he found out that Fanny Owen's engagement had just been broken, news that might have gladdened him in another situation He also visited Maer and The Mount to bid adieu to the Wedgwood relatives and his father and siblings. On October 2, 1831, he returned to London where he bought supplies and consulted with local taxidermists and naturalists on how best to preserve and return the samples he collected while on the voyage. The ship's departure was delayed several times while the ship was prepared. Poor weather delayed the crew even more. Finally, on December 10, they set sail, but were soon turned back by gale winds that rocked the boat and left Darwin miserably nauseated. On December 21, they had what looked like perfect weather and tried again. It was a bad start: FitzRoy almost immediately ran the ship aground, but fortunately nothing was damaged and they quickly set sail again. But when Darwin woke up after his first night's sleep on the ship, he found that they were headed back to England. A wind from the southwest was pushing them back to where they had come from. Finally, after a muted Christmas spent at the port, the ship left on December 27, 1831.

Voyage of the Beagle

1831-1836. The HMS Beagle, captained by Robert FitzRoy, spent five years mapping the coast of South America. Charles Darwin joined the Beagle as a naturalist and it was on this trip that he made many of the observations that contributed to his invention of the theory of evolution by natural selection.

Voyage of the Beagle Part II

At the beginning of the voyage of the HMS Beagle, Darwin was almost incapacitated with nausea. He swung miserably in his hammock in the small cabin he shared with several of the ship's officers or hung by the rail of the ship. Eventually, the nausea passed away and he was able to focus on the voyage itself. The ship's first stop was meant to be Tenerife in the Canary Islands, the same place that Darwin had hoped to visit with Henslow. Unfortunately, because of a recent cholera outbreak in England they would have been quarantined for twelve days before landing, so Captain FitzRoy gave the order to set sail for St. Jago in the Cape Verde Islands, 300 miles off the African coast. Along the way, Darwin began his work as a naturalist by collecting plankton. When they landed at St. Jago he hiked through the volcano hills, encountering his first tropical jungle in a small valley and seeing real evidence of geological change: a layer of compressed sea shells in the cliffs thirty feet above sea level. Leaving St. Jago on February 8, 1831, they stopped at St. Paul's Rocks to kill birds for food, then crossed the Equator on February 16. They reached South America at Bahia, at All Saints' Bay, on February 28. They spent several weeks there before departing for Rio on March 18. Upon arriving, on April 5, Darwin received letters from home for the first time since leaving England. He was surprised to learn that Fanny Owen, who had just broken off an engagement before he left, was now married to another man. While the Beagle surveyed the coastline, Darwin explored the interior, riding with gauchos into the Brazilian jungle from a home base in a rented cottage on Botafogo Bay. He starting filling books with notes on the flora, fauna, and geological formations he encountered. He hunted and collected, setting aside samples to be sent to Henslow in England. On July 7, they continued south to Montevideo. For the next few months the Beagle surveyed up and down the coast while Darwin explored on land. His most exciting find was a fossil megatherium, an extinct ground-dwelling relative of the sloth, discovered in a cliff face at Punta Alta on September 22. Somewhere in the back and forth between Montevideo and Buenos Aires, Darwin found time to assemble his first box of samples and send it off to Henslow. On December 18, 1832, they finally set sail for Tierra del Fuego at the southern tip of South America. There Darwin was shocked to meet the native people, the Fuegians, who seemed to him to be hardly human. In January 1833, on their way to the western coast of Tierra del Fuego, they were almost sunk by bad weather and enormous swells. But they made it safely to the home territory of the Fuegians they had brought on board from England, two men and a woman who had been taken hostage by FitzRoy on a previous trip. They dropped off the Fuegians along with a British missionary who hoped to spread Christianity among the 'heathen' Fuegians. But when the Beagle returned nine days later all of the missionary's belongings had been stolen and the shaken missionary asked to be taken back on board. The next few months saw the Beagle return to the east coast of South America, stopping by the Falkland Islands of the coast of Argentina and then returning to Montevideo. While a second ship that FitzRoy had bought in the Falklands was being refitted for the journey around the Horn, Darwin headed off into the interior, traveling 200 miles in two weeks and killing eighty different kinds of birds, as well as other species, along the way. He continued to send his samples to Henslow. The Beagle finally headed south again in December 1833, passing Port Desire and Port St. Julian on its way through the Straits of Magellan to where the hostage Fuegians had been dropped off months before. There they found that all the new habits taught the Fuegians in England had worn off: they were back to living as they had before. Then, once again, the Beagle returned to the Falklands and Montevideo for another survey of the coast. Darwin headed inland towards the Andes with a group of men and supplies, but provisions ran low and they were forced to turn back before reaching them. Fortunately Darwin knew he would have a chance to reach them from the other side when the Beagle went to Chile. They finally made it around the Horn and arrived at the island of Chiloé, off the west coast of southern South America, on June 6, 1834. From there they went to Valparaiso on July 23. Since it was winter, it was too dangerous to reach the Andes proper, but Darwin made it to the foothills in August, returning through Santiago. There was a brief scare when he returned: FitzRoy had apparently had a breakdown because of doubts about the accuracy of his measurements on the eastern coast of South America, and had resigned his captainship. Fortunately he officers convinced him to resume his post and it was resolved that there was no need to return to the east coast for further measurements. In February 1835, Darwin experienced an enormous earthquake that left local cities in ruins. In March, he finally achieved his dream of seeing the Andes up close, having received some financial help for the expedition from his father, Robert. After returning from the successful Andes expedition Darwin rejoined the Beagle for the trip north to Lima, where they arrived on July 19, 1835. Unfortunately, political unrest was such that they were confined to the port, unable to enter the city itself. They finally headed west into the Pacific two months later, catching their first glimpse of the Galapagos Islands, which Darwin was later to make famous, on September 15.

The Voyage of the Beagle Part III

The Galapagos Islands were formed by the eruption of volcanoes. Darwin was shocked at the broad expanses of black, hardened lava, and by the wildlife he saw living on it. Volcanic cones dotted the landscape. Scurrying or sauntering among them were marine iguanas, crabs, birds, lizards, turtles, and giant land tortoises weighing eighty pounds or more. The crew immediately set about gathering food: they killed eighteen tortoises on the first island they landed on, Chatham, and carried them on board. Darwin collected as much of the fauna as he could lay his hands on. On September 23rd, they landed on another island in the Galapagos, Charles Island, where they found a small settlement. On the 28th they moved on to Albermarle, the largest of the islands. On each island Darwin gathered the species he found. He noticed that the birds that he had collected on Chatham differed from those he found on Charles and Albermarle, and he also heard the local residents claim that they could tell by looking at the shape of the shell which of the islands a tortoise had come from. But he was careless in his collecting, and for the most part he failed to label his species by the island on which he had found them, assuming for the most part that they were the same species on each island. The finches in particular bewildered him: there seemed to be different kinds, but as far as he could tell they mixed together in flocks almost randomly, and he could see no pattern in the differences. There was no fresh water on the Galapagos, so the Beagle started to run low. Fortunately they ran into an American ship that generously gave water to tide them over. Stopping back at Chatham, they killed another thirty tortoises and some iguanas to serve as supplies for the voyage across the Pacific. Darwin also got a young tortoise, which he kept alive as a pet and living specimen. On October 20, 1835, about a month after arriving, they finally left the Galapagos and headed towards Tahiti. It took about four weeks of sailing on the high seas to cover 3200 miles and arrive in Tahiti in mid-November. From there they went to New Zealand (December 19) and Australia (January, 1836), stopping in Tasmania (February 5) and at several points along the Australian coast. In Australia Darwin saw his first platypus up close and also managed to bag a rat kangaroo, though he was disappointed not to have caught a real one. He observed the differences between placental and marsupial animals, as well as the similarities: despite the radical differences in their reproductive systems, these two groups of animals seemed to be equally well adapted to their environments, and often in strikingly similar ways. In Tasmania he observed the marine life: corals, plants, and algae. As the Beagle moved into the Indian Sea he carefully studied the islands and reef formations he came across. On May 31, 1836, the Beagle reached the southern tip of Africa, the Cape of Good Hope, and took a break on shore in Cape Town. Darwin was welcomed by the local scientific aristocracy, shown local geology and had a meeting with the eminent Sir John Herschel. He also received a letter that carried news that made him even more excited to return to England. Henslow had edited and published ten of his letters in a booklet that was receiving rave reviews from the scientific community. As the Beagle left Cape Town and started the long journey north to England, Darwin began organizing his notes and samples, knowing that after all his work he would still have an enormous task lying ahead of him when he reached England. He would have to make sense of about 1300 pages of notes on geology, about 370 pages on zoology, a catalog of 1529 collected species and 3907 other specimens. Fortunately he knew that his return was being awaited eagerly and that he would have support from the scientific community when he returned. Geologist Charles Lyell, whose Principles of Geology Darwin had faithfully read during the first few years of his journey, was enthusiastic about his discoveries, as was Adam Sedgwick, the professor with whom he had spent a summer month exploring the geology of North Wales. After stopping at several familiar points along the way north, including St. Jago where the Beagle had made its first landing five years before, they finally arrived in England on October 2, 1836.

EQ #2: Why were the Galapagos Islands important to the formation of Darwin's theory of evolution?

The Galapagos Islands were important to the formation of Darwin's theory of evolution because they showed that species in isolation tended to evolve in ways that suited their environments. Although Darwin did not immediately comprehend the importance of the different varieties of tortoises and finches that he observed in the island, he later saw that the differences in finch's beaks demonstrated the ability of evolution to fine tune a species to fit the particular demands of an environment.

EQ #3: What impact did Darwin's health have on his life and career?

The cause of Darwin's health problems has remained a mystery. Some argue that he contracted a disease while on the Beagle; others think that his physical symptoms were the result of high levels of stress and emotional repression. In any case, the effect of his illness was to isolate him from society at Down House. He continued to see people, and his correspondence was enormous, but he spent most of his time alone or in the company of Emma. This solitude meant that he was distant from the controversies and politics of science, and was able to focus on his own theories and observations without the pressures of academic fighting or the responsibilities of teaching or mentoring. This isolation helped him develop his theory of evolution, but it may also have helped delay the time at which he finally announced it to the scientific community and the public.

EQ #1: The theory of evolution had been around long before Darwin's Origin of Species? What new elements made the Origin of species so important, and why?

Theories of evolution before Darwin, such as those of his grandfather Erasmus Darwin, did not explain how species could evolve without help from an outside guiding force, such as a botanist who killed specific kinds of flowers or a dog breeder who bred for a specific trait. Darwin proposed natural selection. Natural selection is the pressure for species with advantageous traits to survive while those with less advantageous traits died. Darwin said that natural selection explained evolution. The Origin of Species was also important because it was the first time that a strong body of evidence, taken from a wide range of species and environments, had been assembled in support of evolution.