“As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected”
Darwin spent the summer of 1825 as an apprentice doctor, helping his father treat the poor of Shropshire, before going with Erasmus to the University of Edinburgh. He found lectures dull and surgery distressing, so neglected his medical studies. He learned taxidermy from John Edmonstone, a freed black slave who had accompanied Charles Waterton in the South American rainforest, and often sat with this “very pleasant and intelligent man”.Darwin was later recommended as a suitable (if unfinished) naturalist for the unpaid position of gentleman’s companion to Robert FitzRoy, the captain of HMS Beagle, which was to leave in four weeks on an expedition to chart the coastline of South America. His father objected to the planned two-year voyage, regarding it as a waste of time, but was persuaded by his brother-in-law, Josiah Wedgwood, to agree to his son’s participation.
The voyage lasted almost five years and, as FitzRoy had intended, Darwin spent most of that time on land investigating geology and making natural history collections, while the Beagle surveyed and charted coasts. He kept careful notes of his observations and theoretical speculations, and at intervals during the voyage his specimens were sent to Cambridge together with letters including a copy of his journal for his family. He had some expertise in geology, beetle collecting and dissecting marine invertebrates, but in all other areas was a novice and ably collected specimens for expert appraisal. As HMS Beagle surveyed the coasts of South America, Darwin theorised about geology and extinction of giant mammals. Three Fuegians on board, who had been seized during the first Beagle voyage around February 1830 and spent a year in England, were taken back to Tierra del Fuego as missionaries. Darwin found them friendly and civilised, yet their relatives seemed “miserable, degraded savages”, as different as wild from domesticated animals. To Darwin the difference showed cultural advances, not racial inferiority. Unlike his scientist friends, he now thought there was no unbridgeable gap between humans and animals.
A year on, the mission had been abandoned. The Fuegian they’d named Jemmy Button lived like the other natives, had a wife, and had no wish to return to England. The Beagle investigated how the atolls of the Cocos (Keeling) Islands had formed, and the survey supported Darwin’s theorising. FitzRoy began writing the official Narrative of the Beagle voyages, and after reading Darwin’s diary he proposed incorporating it into the account. Darwin’s Journal was eventually rewritten as a separate third volume, on natural history.
Darwin’s book was half way when, on 18 June 1858, he received a paper from Wallace describing natural selection. Shocked that he had been “forestalled”, Darwin sent it on to Lyell, as requested, and, though Wallace had not asked for publication, he suggested he would send it to any journal that Wallace chose. There was little immediate attention to this announcement of the theory; after the paper was published in the August journal of the society, it was reprinted in several magazines and there were some reviews and letters, but the president of the Linnean remarked in May 1859 that the year had not been marked by any revolutionary discoveries. On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life (usually abbreviated to On the Origin of Species) proved unexpectedly popular, with the entire stock of 1,250 copies oversubscribed when it went on sale to booksellers on 22 November 1859. In the book, Darwin set out “one long argument” of detailed observations, inferences and consideration of anticipated objections. His only allusion to human evolution was the understatement that “light will be thrown on the origin of man and his history”. His theory is simply stated in the introduction: As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected.
Today, 150 years after the publication of that book, controversy still trails the book, not because the position therein were not worth spreading but simply because it did what other book did not: challenged the existing belief of the time.
Indeed, Charles Darwin evolution theory called for a critical examination of the religious creationism.
That is his greatest gift to humanity!
http://en.wikipedia.org/wiki/Charles_Darwin