Charles Darwin first explained the theory of evolution and the process of natural selection. Much like his grandfather Erasmus Darwin, Charles had an inquisitive and scientific mind, but he was not interested in becoming a doctor, as was his father. When he also did not seem interested in pursuing a career in the ministry, Charles's father reluctantly gave his son permission to embark upon a voyage aboard a survey ship, a trip that would foster foster Darwin's interest in biology.
This five-year voyage on the HMS Beagle was not only a life-changing event for Darwin, but also for the world. From his inquisitive study of Captain Fitzroy's books on geology that were on board to his meticulous observations and recordings as he observed the birds and other animals on the Galapagos Islands, Darwin noted the differences within the same species, depending upon which of the islands they inhabited. For instance, there was one species of birds found in a few locations. But, on one rocky location without vegetation where there were no predators, the birds appeared to have almost no wings and were unable to fly. With an ornithologist associate, Darwin studied the variety of finches found on the island; he was curious about them since there is no such variety 600 miles to the east, in South America. But, on the Galapagos islands, they varied in the beaks because they seemed to be obliged to adapt to differing environments. For example, one variety of finches had a longer, narrower, longer beak to enable them to obtain nectar from flowers near them.
Darwin's close observations led him to theorize that animals adapted to their environments in order to survive; this phenomenon is called natural selection. From his observation of natural selection, Darwin launched his theories of evolution. For example, in the industrial cities of Manchester and Liverpool and London, soot and smoke were emitted. This material landed on the wings of moths in the area, causing them to be darker than they normally would be. Because they were dark, the birds could not see them to eat them, and they all survived. After a length of time, their offspring were dark, as well, so somehow the darkness got into the genetic code. This is the concept of evolution. It is worthy of note here that "unlike Lamarck, Darwin did not believe that evolution inevitably produces more complex life forms and that the ultimate result of this process is humans. " He simply believed that through adaptation and natural selection (survival of the fittest), animals evolved so that they could better survive.
In 1859, Darwin published his On the Origin of Species, which was the first of a series of books that explain the role of natural selection in the biological evolutions of the many species.
Charles Darwin was the first to describe the phenomenon of speciation.
Speciation is the process by which a population diverges into two seperate species that cannot mate. One of the most common causes of speciation is geography. In Darwin's example of Galapagos finches, groups of finches were seperated by bodies of water. Each island had different resources therefore each population of finches developed different traits. Over time these minute adaptations became intrinsic to the finches' genes and they lost their ability to cross breed.