Darwin's Theory Of Evolution example essay topic

The Life of Charles Darwin Charles Darwin was born on Feb. 12. His full name is Charles Robert Darwin. He died on April 19, 1882. Darwin was an English naturalist known for his theory of evolution and for its operation, known as Darwinism. His evolutionary theories, mostly in two works: On the Origin of Species by Means of Natural Selection (1859) and The Descent of Man, and Selection in Relation to Sex (1871) -have had an important influence on scientific thought. Charles was the son of Robert Darwin, who had one of the largest medical practices outside of London, and the grandson of the physician Erasmus Darwin, and of the artisan-entrepreneur Josiah Wedgwood.

Darwin enjoyed a secure position in the upper middle class that provided him with social and professional advantages. Darwin's mother died when he was eight years old. He enjoyed a fairly good childhood with his sisters and an older brother. During school he was interested in specimen collecting and chemical investigations. Though while at the Shrewsbury school, where he was an uninspired student, Dr. Samuel Butler, publicly criticized Darwin for wasting his time with chemical experiments. At age 16 he was sent to study medicine at the University of Edinburgh, where he was disgusted by surgery performed without anesthetics.

During his two years in Scotland, Darwin benefited from a friendship with the zoologist Robert Grant, who introduced him to the study of marine animals. < Tab/> Disappointed by Darwin's lack of interest for medicine, his father sent him to the University of Cambridge in 1827 to study divinity. At the time Darwin remained true to the standard beliefs of the Church of England. He enjoyed hunting, shooting, riding, and sporting friends. Guided by his older cousin William Darwin Fox, Darwin met the circle of Cambridge scientists led by the botanist John Stevens Henslow. Soon a regular at Henslow's open houses, Henslow encouraged Darwin's interest in science and confidence in his own abilities. On leaving Cambridge in the spring of 1831 Darwin, at Henslow's recommendation he accompanied Adam Sedgwick, professor of geology at Cambridge, on a three-week tour of North Wales to learn geologic fieldwork.

In August 1831, at Henslow's recommendation to the Admiralty, Darwin was invited to sail as the naturalist on HMS Beagle. The ship was to survey the east and west coasts of South America and continue to the Pacific. At first Darwin's father refused permission because it was dangerous and would not advance Charles in his career. But eventually he changed his mind and gave permission for his son to go. On Dec. 27, 1831, Charles Darwin sailed from Plymouth, England, on the Beagle. The voyage, planned for two years, lasted five, during which Darwin kept notes and sent back geologic and biologic specimens.

There is no doubt that the years he spent exploring the South American continent and the offshore islands of the Galapagos improved his skills as a collector, observer, and theorist. Often seasick, he spent long periods of time ashore whenever the opportunity arose. He braved his way through armed political rebellions, and rode with the gauchos in Argentina. He joined the crew in towing the ship's boats upstream and once rescued the expedition by running to save a boat from a tidal wave. He seemed to enjoy danger. About 1,800 miles southwest of the Canary Islands the Beagle visited a volcanic island in the Cape Verde Islands.

From the harbor Darwin saw a band of white rock extending horizontally at a height of about 45 feet above the base of the sea cliffs. The formation contained numerous shells, almost all of which could be found on the coast. Darwin reasoned that a stream of lava from the ancient volcanoes had flowed over what had been ancient seabed, baking it to form the hard white rock. Darwin also realized that the island's surface had been formed by a series of volcanic events, not a single dramatic one. Later, in Chile, Darwin witnessed his first earthquake. He saw the land rise before his eyes.

Then, after crossing the Andes in 1835, he had found fossil shells at an elevation of 12,000 feet, and he theorized that a chain of sub oceanic volcanoes had poured enormous quantities of lava that formed the Andes. The data Darwin collected on the Beagle provided him with material for three books on South American geology. However now, his theories of continental change have been proven obsolete by the theory of plate tectonics. Philosophical Society and the Geological Society of London brought him celebrity in scientific circles even before his return.

Darwin's geologic theories were important for geology and to his scientific development. Many of the rocks he examined contained fossils, and his constant exposure to the evidence of extinct species and the similarity of many of them to living species. Through all this he kept asking himself, by what method did new species replace extinct ones? During the voyage Darwin developed confidence in the ability to take hold of a problem and work at it steadily. The isolation of the voyage taught him to think for himself. His geologic thought on a continental scale encouraged him to search for universal laws.

The voyage of the Beagle transformed Darwin into an independent scientist who had the courage to embrace the unorthodox idea of the transmutation of species. When Darwin returned to England in 1836 he was welcomed by the scientific society as a colleague and was made a member of the Geological Society. The next year he was elected to its governing council. In 1838 Darwin was elected to the Athenaeum, the exclusive club for men distinguished in literature, art, or science, and in 1839 he was elected to the Royal Society. He started preparing his Journal of Researches into the Geology and Natural History of the Various Countries Visited by H.M.S. Beagle, which was published in 1839. This book established the clear style that makes all of Darwin's works both accessible and convincing.

Darwin was also preparing his geology books and watching the analysis and publication of The Zoology of the Voyage of H.M.S. Beagle. Privately Darwin had begun a series of notebooks in which he answered the species problem. He collected facts about species through letters and discussions with breeders, gardeners, naturalists, and zookeepers, as well as through reading other peoples work. Darwin kept this interest secret while he gathered evidence to his theory of organic evolution. Darwin's ideas were not only radical but also could have been seen as blasphemy and treason. Even today many devout Christians do not accept Darwin's theory of evolution.

England at the time understood the natural world as one in which God could be seen in the creation of new species of plants and animals that appeared to come into existence to replace those that became extinct. Upon his return from the voyage Darwin had turned over his specimens to experts in Cambridge and London. In South America he had found fossils of extinct armadillos that were similar but not identical to the living animals. In Argentina he had seen species vary from region to region such as the giant ostriches on the plain were replaced to the south in Patagonia by much smaller species, both of were similar to but different from the African ostrich. He had been concerned by the fact that the birds and tortoises of the Galapagos Islands off the western coast of Ecuador tended to resemble species found on the nearby continent, while animals of similar neighboring islands in the Galapagos had different animal populations. In London Darwin learned that the finches he had brought from the Galapagos belonged to different species.

He also learned that the mockingbirds were of three distinct species. Also that the Galapagos tortoises were at least two different species and that they were native to the islands but to neither of the American continents. After Darwin received these reports, his doubts about the species turned into a belief in transmutation. In March 1837 he wrote in his notebook that species changed from one place to another or from one age to the next. He continued analyzing his data, searching for a system for this process. Darwin in his Autobiography remembered his realization that given the struggle for existence everywhere, "favorable variations would tend to be preserved, and unfavorable ones to be destroyed".

The result of this would be the formation of new species. This is how he came to the principle of natural selection. Darwin saw competition between individuals of a single species. He recognized that within a local population the individual with, the sharper beak, the longer horn, or the brighter feather might have a better chance to survive and reproduce than other individuals. If useful traits were passed on to new generations, they would eventually be predominant in future populations. Darwin changed the focus of evolutionary study from between to within species.

He saw natural selection as the system by which advantageous variations passed on to succeeding generations and by which the traits of individuals that were less competitive gradually disappeared from populations. After he discovered natural selection, Darwin then had to verify it, he made various inquires to plant and animal breeders. He hoped to learn from their experience with artificial selection to how natural selection worked. He had discovered during his voyage, different species appeared on different landmasses. Darwin solved this question of geographic distribution by assigning the spreading of populations of ocean islands to the power of wind and water. The theory of the evolution of species thus solved many questions in relative anatomy and paleontology.

The idea of organic evolution was not new. It had been suggested a generation earlier by Erasmus Darwin and by various other naturalists. But none of these earlier naturalists had presented either a system or evidence for the process. Though lack of an apparent system of inheritance eventually encouraged him to accept the latter idea, Darwin's theory was fixed in direct observation and an attempt to discover universal laws. Darwin rejected the popular view that organisms are perfectly adapted to their environment. He viewed the natural world as caught in a constant struggle between competing individuals that have different degrees of fitness.

Others had seen struggles but always between species, never within them. He recognized that it is the competition within a species leading to the survival of individuals with advantageous traits that eventually brings about the evolution of a new species. By 1842 Darwin was sure enough in his theory to write a short rough copy. Then in 1844 he wrote a longer version, which he showed to his friend, the botanist Joseph Dalton Hooker.

Cautious of presenting his theory to the public, Darwin spent the next decade concentrating on a paper on barnacles. During this time the intellectual environment in England changed and discussions about evolution became ordinary. Darwin still withheld publishing his theory. But he waited to long because on June 18, 1858, Alfred Russell Wallace, published a paper that summarized the theory that Darwin had been working on for 20 years. Darwin then began work on a summary of the larger document that he had begun two years earlier. This paper, On the Origin of Species by Means of Natural Selection, or The Preservation of Favored Races in the Struggle for Life, was published on Nov. 24, 1859.

The first edition sold out immediately, and by 1872 the work had run through six editions. The theory was accepted in most scientific circles, with the exception of a few holdouts. After the publication of the Origin, Darwin continued to write. While friends, defended the theory before the public. Darwin completed the clarification of his theory in his next three books, which all added on to of the Origin. Darwin discussed human evolution in The Descent of Man, and Selection in Relation to Sex, in which he detailed the controversial subject.

He expanded the range of evolution to include moral and spiritual as well as physical traits and indicated man's psychological as well as physiological similarities to the great apes. The second half of the book elaborated upon the theory of sexual selection. Darwin observed that in some species males battle other males for access to certain females. But in other species, such as peacocks, there is a system in which the females select males according to such traits as strength. Although most scientists rejected Darwin's description of female choice at the time, he defended this view until the end of his life.

While not unanimously accepted today, the theory of female choice has many supporters among evolutionary biologists. The last of Darwin's sequels to the Origin, The Expression of the Emotions in Man and Animals (1872), was an attempt to remove the last barrier supposed to exist between human and nonhuman animals. The idea that the expressions of such feelings as suffering, anxiety, grief, despair, joy, love, devotion, hatred, and anger are unique to human beings. Darwin linked studies of facial muscles and the release of sounds with the matching emotional states in man and then argued that the same facial movements and sounds in nonhuman animals express similar emotional states. This book laid the base for the study of ethnology, neurobiology, and communication theory in psychology. Throughout his life his interests changed over the years from geology to zoology to botany.

In his later works he included hypothetical analysis, while in his earlier works had contained mostly data. In explaining the interdependence of bees and orchids, Darwin noted that flowers that are pollinated by the wind have little color, while those that need to attract insects have brightly colored petals and sweet-smelling nectarines. He continued experiments for another 12 years on 57 species and described his results in The Effects of Cross and Self Fertilization in the Vegetable Kingdom (1876). Here he developed the idea that there are genetic advantages in having two sexes in both the plant and animal kingdoms. To ensure cross-fertilization, which, as he knew from experiments, produced healthier, stronger offspring. Darwin worked alone at home, leading the life of an independent scientist.

Money from his father made it unnecessary for Charles to seek employment. After his return from the voyage Darwin knew he would never become a clergyman like his mentor, Henslow. He proposed to his first cousin Emma Wedgwood, which he married on Jan. 29, 1839. She brought fortune, devotion, and considerable skills that allowed him to work for the next 40 years.

Newly married, the Darwin's moved into a house in London, but within a few years Darwin's increasingly poor health made them to move to the country. In 1842 the Darwin's moved into a house in the village of Downe, Kent, only 16 miles from London. Charles and Emma Darwin had 10 children; two died in infancy and a third, Anne, died at age 10. The surviving five sons went away to school.

George, Francis, and Horace became distinguished scientists, and Leonard, a major in the royal army, was an engineer. William Erasmus was not noteworthy, as were his sisters, who prepared at home to follow their mother into marriage. Henrietta married while Elizabeth remained single. Darwin was devoted to his wife and daughters but treated them as children. Over the course of his life he made important contributions to biology and many of his theories are still strongly supported even today..