Like many modern students, Charles Darwin exceeded only in subjects that intrigued him. Although his father was a physician, Darwin was uninterested in medicine and he was unable to stand the sight of surgery. He did eventually obtain a degree in theology from Cambridge University, although theology too was of minor interest to him. What Darwin really liked to do was to tramp over hills, observing plants and animals, collecting new specimens, scrutinizing their structures, and categorizing his findings.
In 1831, when Darwin was only 22 years old, the British government sent Her Majesty's Ship Beagle on a 5 year expedition that would take them first along the coastline of South America and then onward around the world. As was common on such expeditions, the Beagle would carry along a naturalist to observe and collect geological and biological specimens encountered along the route. Thanks to the recommendation of one of Darwin's previous college professors, he was offered the position of naturalist aboard the Beagle.
The Beagle sailed to South America, making many stops along the coast. Here Darwin observed the plants and animals of the tropics and was stunned by the diversity of species compared with Europe.
Perhaps the most significant stopover of the voyage was the month spent in the Galapagos Islands off of the northwestern coast of South America. It was here that Darwin found huge populations of tortoises; and he found that different islands were home to distinctively different types of tortoises. He then found that on islands without tortoises, pricky pear cactus plants grew with their juicy pads and fruits spread out over the ground. And on islands that had hourdes of tortoises, the prickly pears grew substantially thick, tall trunks, bearing the fleshy pads and fruits high above the reach of the tough mouthed tortoises. He then wondered if the differences in these organisms could have arisen after they became isolated from one another on seperate islands.
In 1836, Darwin returned to England after the 5 years with the expedition. He became established as one of the foremost naturalist of his time. But constantly gnawing at his mind was the problem of the origin of the species.
Darwin sought to prove his ideal of evolution with simple examples. The various breeds of dogs provided a striking example of what Darwin sought to prove. Dogs descended from wolves, and even today the two will readily cross-breed. With rare exceptions, however, few modern dogs actually resemble wolves. Some breeds, such as the Chihuahua and the Great Dane, are so different from one another that they would be considered seperate species in the wild. If humans could cross-breed such radically different dogs in only a few hundred years, Darwin reasoned that nature could produce the same spectrum of living organisms given the hundreds of millions of years that she had been allowed.
Darwin also maintained that seperate species evolve as a result of the principles of natural selection, or survival of the fittest. He knew that many more members of a species are born than can possibly survive. He also postulated that strong positive genes would be bred and rebred into each new generation of animals.
Darwin, contrary to popular belief, never said that human beings evolved from apes. He said that all life began as a primordial soup, with molecules acting on each other. So from the first single celled organism all life came. One single organism, when acted on by several different molecules could give rise to many different species of animals. It is in this way that he stated that Ape and man were similar..each having a similar life's beginning.
Darwin's theories caused the people of the time to begin to question where it was that they actually came from. His response was the book On the Origin of Species. In it he addressed the concerns of the people. He said "It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing in the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms....have all been produced by laws acting around us. These laws, taken in the highest sense, being Growth with Reproduction; Inheritance and Variability...; a Ratio of Increase so high as to lead to a struggle for life, and as a consequence to Natural Selection, entailing Divergence of Character and Extinction of less-improved forms....There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one, and that, whilst this planet has gone cycling on according to the fixded laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved."