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Charles Darwin

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Charles Darwin

Charles Robert Darwin, F.R.S. (February 12, 1809 - April 19, 1882) was a revolutionary English naturalist who laid the foundation for both the modern theory of evolution and the principle of common descent by proposing natural selection as a mechanism. He published this proposal in 1859 in the book The Origin of Species, which remains his most famous work. A worldwide sea voyage aboard the HMS Beagle and observations on the Galapagos Islands in particular provided inspiration and much of the data on which he based his theory.

Early life

A seven-year old Charles Darwin in 1816

Charles Darwin was born in Shrewsbury, Shropshire, England, on the same day as Abraham Lincoln. He was the fifth of six children of Robert and Susannah Darwin (née Wedgwood), and the grandson of Erasmus Darwin, and of Josiah Wedgwood. See also Darwin -- Wedgwood family.

After finishing school, Darwin studied medicine in Edinburgh in 1825. His dislike for dissection and the brutality of surgery at the time led him to leave the medical school in 1827. Whilst there, however, he was influenced by the Lamarckian Robert Edmund Grant.

His father, unhappy that his younger son had not become a physician and fearing that he would become a "ne'er do well", enrolled him at Christ's College, Cambridge, with the hopes of Charles' eventually becoming a parson. He preferred riding and shooting to studying, but while at Cambridge, he came under the intellectual influence of scientific minds such as William Whewell and John Stevens Henslow which (combined with his interest in collecting beetles, which was encouraged by his cousin, William Darwin Fox) resulted in him pursuing natural history.

After taking his degree with honours, Darwin stayed at Cambridge for further studies in geology, where he proved particularly adept. In the summer of 1831, Darwin worked with the great geologist Adam Sedgwick mapping strata in Wales.

Darwin had planned to visit Madeira with some class-mates upon graduation in 1831. These plans, however, fell through. After Darwin finished his studies, Henslow recommended him for the position of naturalist and gentleman's companion to Robert Fitzroy, the captain of the HMS Beagle, which was departing on a five-year expedition to chart the coastline of South America. His father objected to the expedition, thinking it a waste of his son's time, but was eventually persuaded to let him go.

Journey on the Beagle

File:HMSBeagle.jpeg
HMS Beagle, from an 1841 watercolour by Owen Stanley

Darwin's work during the Beagle expedition allowed him to study both the geological properties of continents and isles and a multitude of living organisms and fossils. He collected an enormous number of specimens new to science in a very methodical way, and his specimens sent back to the British Museum were by themselves a significant contribution to science, and made him one of the precursors of ecology. No other collector has rivalled his work since. He also took many detailed notes on everything he observed, which would form the basis for his later work.

During his voyage, he visited the Cape Verde Archipelago, the Falkland Islands, the South American coast, the Galapagos Islands, New Zealand and Australia, meeting primitive peoples, seeing natural wonders, and above all, collecting considerable quantities of specimens.

While in South America, he contracted Chagas' disease from insect bites. Although not fatal, it recurred several times during his life, and prevented him from being particularly active.

Darwin shapes his theory

After returning from the voyage on October 2, 1836, Darwin analyzed the specimens he collected, and noticed similarities between fossils and living species within the same geographic area. In particular, he noticed that every island in the Galapagos Archipelago had its own kind of tortoises and birds that were all slightly different in appearance, favored food etc., but otherwise similar.

In the spring of 1837 ornithologists at the British Museum informed Darwin that the several very different species of birds he had taken in the Galapagos were all finches. This, coupled with a re-reading of Thomas Malthus' 1798 essay on populations, triggered a chain of thought that would culminate in the theory of evolution by natural and sexual selection. He developed the hypothesis that, for example, all the different turtles had originated from a single turtle species, and had adapted to life on the different islands in different ways.

Based on these thoughts, he formulated his ideas about the changes and developments of species in his Notebook on the Transmutation of Species, which was in accordance with Lyell's Principles of Geology and Thomas Malthus' Essay on the Principle of Population, which stated that the size of a population is limited by the food resources available. Realizing the potential of this understanding, Darwin undertook extensive experiments with pigeons and plants, and extensive consultation with pig breeders and other animal husbanders, in an attempt to discover holes in the hypothesis. He took his time with careful research until he had enough evidence, knowing that a great deal of opposition would likely erupt when he presented his theory.

First writings

In 1842, Darwin formulated a short "Pencil Sketch" of his theory and by 1844 had written a 240 page "Essay" which provides an expanded version of his early ideas on natural selection.

Between 1844 and 1858, when he would present his theory to the Linnean Society of London, Darwin wrote his masterpiece, modifying his theory in a number of ways as he wrote.

Darwin published other treatises in science, including an explanation for the creation of coral atolls in the South Pacific, and the story of his voyage aboard the Beagle. Between 1839 and 1843, Darwin's Zoology of the Voyage of H.M.S. Beagle was published in five volumes.

Marriage and children

Emma Darwin, Charles' wife

Darwin married his cousin Emma Wedgwood in 1839. After living for a number of years in London, the couple eventually moved to Down House, in Downe, Kent (which is now open to public visits, south of Orpington). The Darwins had ten children, three of whom died early:

The Origin of Species

Darwin's work brought him a correspondence relationship with Alfred Russel Wallace, working in the islands of the South Pacific and Indonesia. On June 18th 1858, Wallace sought Darwin's ideas on a theory Wallace had developed which almost exactly mirrored Darwin's own work. Darwin's scientific colleagues urged him to go public with the theory, now that it had been independently confirmed. On 1 July, 1858, Darwin's paper entitled The Origin of Species by Means of Natural Selection was read to the Linnean Society in London, jointly with Wallace's paper. Oddly enough, it attracted little notice or controversy.

Darwin's book On the Origin of Species by Means of Natural Selection was published one year later, and was of sufficient interest to have the publisher's stocks completely sold to bookstores on the first day. It would prove to be the most controversial and discussed scientific book ever written.

It provoked an outraged response from the Church. A large meeting was organised in Oxford where 'Soapy Sam' Wilberforce, the Bishop of Oxford, numerous Clergy and Robert Fitzroy (the Captain of HMS Beagle) argued against Darwin, Thomas Huxley and their Evolutionist supporters. On being asked by Wilberforce, whether he was descended from monkeys on his grandfather's side or his grandmother's side, Huxley, recognizing the stupidity of the question, apparently muttered to himself: "The lord has delivered him into my hands", and then replied that he "would rather be descended from an ape than from a cultivated man who used his gifts of culture and eloquence in the service of prejudice and falsehood" [several alternative versions of this supposed quote exist, see Wilberforce and Huxley: A Legendary Encounter].

Charles Darwin himself did not actively defend his theories; he was constantly in ill health, and Huxley was skilled enough to handle the situation for him.

Later works and death

In several of his later books The Variation of Animals and Plants Under Domestication (1868), The Descent of Man, and Selection in Relation to Sex (1871) and The Expression of Emotions in Animals and Man (1872), Darwin expanded on many topics introduced in Origin of Species. The Descent of Man, in particular, aroused even greater argument since it theorized that humanity was descended from apes. Forever afterward, Darwin would be characterized as "the monkey man," and cartoons often depicted him as part ape (see below).

The value of Darwin's work was appreciated throughout the scientific community. He became a member of the Royal Society of London in 1839 (on the basis of his collecting during his voyages) and of the French Academy of Sciences (l'Académie des Sciences) in 1878.

The classic image of Darwin as an old man

Darwin died in Downe, Kent, England, on 19 April 1882 was given a state funeral, and interred in Westminster Abbey near Isaac Newton.

Darwin was given particular recognition in 2000 when his image appeared on the Bank of England ten pound note, replacing Charles Dickens. His impressive and supposedly hard-to-forge beard was reportedly a contributing factor in this choice.

Before Darwin

Prior to the nineteenth century, the accepted theory for the extinction of species was called Catastrophism. This propounded the belief that animals and plants were periodically wiped out as a result of natural catastrophes and that their places were taken by the creation of new species ex nihilo (out of nothing). The extinct organisms could then be observed in the fossil record and their replacements were considered to be immutable. This explanation fitted in neatly with the story of the Flood in the Bible.

In the early nineteenth century, several alternative and radical ideas started to emerge. Charles's grandfather Erasmus hypothesized that all warm-blooded animals sprang from a single living "filament" long, long ago. Probably the most important one was developed by Jean-Baptiste Lamarck (1744-1829) who observed that every new generation inherits some characteristics of its ancestors. His suggested mechanism for this process was that an individual's traits or organs became enhanced with repeated use, and weakened or removed by disuse. These changes would then be passed directly on to its offspring.

Between 1830-1833, the eminent British geologist Sir Charles Lyell released a three volume publication called Principles of Geology which effectively rejected the Catastrophism Theory. This gave additional support to the concept of uniformitarianism, which stated that the Earth's surface gradually altered over eons of time by the constant action of natural geological processes.

Darwin's theory of evolution

Darwin's theory of evolution is based on five key observations and inferences drawn from them. These observations and inferences have been summarized by the great biologist Ernst Mayr as follows:

  • First, species have great fertility. They make more offspring than can grow to adulthood.
  • Second, populations remain roughly the same size, with modest fluctuations.
  • Third, food resources are limited, but are relatively constant most of the time. From these three observations it may be inferred that in such an environment there will be a struggle for survival among individuals.
  • Fourth, in sexually reproducing species, generally no two individuals are identical. Variation is rampant.
  • And fifth, much of this variation is heritable.

From this it may be inferred: In a world of stable populations where each individual must struggle to survive, those with the "best" characteristics will be more likely to survive, and those desirable traits will be passed to their offspring. These advantageous characteristics are inherited by following generations, becoming dominant among the population through time.

This is natural selection.

It may be further inferred that natural selection, if carried far enough, makes changes in a population, eventually leading to new species. These observations have been amply demonstrated in biology, and even fossils demonstrate the veracity of these observations.

Darwin imagined it might be possible that all life is descended from an original species from ancient times. DNA evidence supports this idea.

Response to Darwin's theory

Caricature of Darwin as an ape in the Hornet magazine

After the publication of Darwin's book, evolution as the means of natural selection was widely discussed, particularly by the religious and the scientific communities. Though Darwin was supported by some scientists (e.g., T.H. Huxley), others hesitated to accept the theory due to the unexplained ability of individuals to pass their special abilities to their offspring. The last point remained a mystery until the existence of genes was discovered (Gregor Mendel had worked out his laws of heredity by 1865, but they were ignored by the scientific community, including Darwin, until the 20th century).

In 1902 Peter Kropotkin published the book Mutual Aid: A Factor of Evolution, challenging Darwin's Theory as too narrow. In 1874, the theologian Charles Hodge accused Darwin of denying the existence of God by defining humans to be a result of a natural process rather than a creation designed by God. Darwin's theory is now backed up by the comparison of DNA from different organisms which shows the closeness of their relationship.

Today, whilst the overwhelming majority of biologists consider Darwin's basic theory correct, a significant fraction of the general population, particularly in the United States, disagree mainly on religious grounds ( see creationism).

Evolution is in complete contradiction with many of the legendary or religious stories of how the world's life originated; therefore, those that accepted the theory grew more skeptical of the Bible and other religious sources. As Hodge pointed out, evolution does not seem to originate from a divine source, and some viewed God as a less powerful force in the universe.

The theory of evolution was also applied to the human world (politics, economics, etc.). The most famous of these doctrines is Social Darwinism, although many argue that it is not accurately derived from Darwin's work.

Darwin's theory changed the way humans saw themselves and their world. If one accepted that humans were descended from animals, it becomes clearer that humans are animals themselves. The natural world took on a darker tinge in the minds of many, as animals were understood to be in a constant state of competititon with one another. The world was also seen in a less permanent fashion; since the world was apparently much different millions of years ago, it dawned on many that the impact of human beings would lessen and perhaps disappear altogether over time.

Contrary to popular opinion, Darwin did not "discover" evolution as it was accepted by many since the beginning of the 1800s. Instead, he and Wallace discovered the first really coherent mechanism that explains how evolution occurs: (natural selection).

Other important aspects of Darwin's overall theory were: common descent, sexual selection, gradualism, and pangenesis. It is important to remember that Darwin's version of natural selection was different from that presented by Wallace, in that Darwin held that natural selection was continuously operating whereas Wallace argued that selection only occurred when the environment changed.

Darwin is included in the top 10 of the 100 Greatest Britons poll sponsored by the BBC and voted for by the public.

Philosophical implications

According to Mayr, Darwin's evolutionary thinking rests on a rejection of essentialism, which assumes the existence of some perfect, essential form for any particular class of existent, and treats differences between individuals as imperfections or deviations away from the perfect essential form. Darwin embraced instead what Mayr calls population thinking, which denies the existence of any essential form and holds that a class is the conceptualization of the numerous unique individuals. Individuals, in short, are real in an objective sense, while the class is an abstraction, an artifact of epistemology. This emphasis on the importance of individual differences is, of course, necessary if we are to believe that the mechanism of evolution, natural selection, operates on individual differences.

Mayr claims essentialism had dominated Western thinking for two thousand years, and that Darwin's theories thus represent an important and radical break from traditional Western philosophy. Ripples of Darwin's thought can now be seen in fields such as economics and complexity theory, suggesting that Darwin's influence extends well beyond the field of biology.

As an interesting aside, Darwin could be regarded as the first organism in four billion years of life on earth to realise how he had come to exist.

Views on religion

See Charles Darwin's views on religion.

See also

  1. 'Descent of Man'

http://www.infidels.org/library/historical/charles_darwin/descent_of_man/

  1. 'Formation of vegetable Mould Through the Action of Worms'

http://digital.library.upenn.edu/webbin/gutbook/lookup?num=2355

  1. 'Geological Observations of South America'

http://digital.library.upenn.edu/webbin/gutbook/lookup?num=3620

  1. 'Geological Observations of Volcanic Islands'

http://digital.library.upenn.edu/webbin/gutbook/lookup?num=3054

  1. 'Movement and Habits of Climbing Plants'

http://digital.library.upenn.edu/webbin/gutbook/lookup?num=2485

  1. 'Structure and Distribution of Coral Reefs'

http://digital.library.upenn.edu/webbin/gutbook/lookup?num=2690

  1. 'Variation of Plants and Animals Under Domestication (PDF Format)'

http://www.esp.org/books/darwin/variation/facsimile/title3.html

  1. 'Voyage of the Beagle'

http://www.infidels.org/library/historical/charles_darwin/voyage_of_beagle/

  1. 'Autobiography of Charles Darwin'

http://digital.library.upenn.edu/webbin/gutbook/lookup?num=2010

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