Charles Darwin was an English naturalist who was most famous for his groundbreaking theories of evolution. His theories, since known as Darwinism, were put forth in two books – On the Origin of Species by Means of Natural Selection (1859) and The Descent of Man, and Section in Relation to Sex (1871).
Charles Darwin was born in 1809. He was the son of a well-known doctor, Robert Darwin, and the grandson of author and physician Erasmus Darwin. As a member of the professional class, he enjoyed all the advantages of his station – social, professional, and educational.
As a child, Darwin showed a keen interest in the natural world. When he turned 16, he went to the University of Edinburgh to study medicine. Repelled by the lack of anesthetics, Darwin was fascinated by zoology and geology.
Having failed in his study of medicine, Darwin then went to the University of Cambridge to study divinity. He was an undistinguished student, but met entomologists, botanists, and other scientists who encouraged his natural interests.
In 1831, Darwin joined the HMS Beagle as the ship naturalist. This volunteer post is to help the crew survey South America and the Pacific Islands. Over this five-year voyage, Darwin maintained careful records and preserved biologic and geologic specimens.
His observations, particularly around the Galapagos Islands, led him to develop a groundbreaking new theory. Until this time, creationism was the accepted belief. Yet what Darwin saw made him believe that animals could change over time, becoming new species.
Darwin kept in contact with other scientists, as well as gardeners, breeders, and zookeepers. His appetite for information was enormous, and he read voraciously. In the Galapagos, he observed that certain birds and turtles on the Galapagos Islands resembles those on South America, while other islands had completely unique birds and animals. This did not fit in with the mainstream religious notion that God had created all the animals long ago.
Darwin began to doubt that species were fixed into one form. Instead, he believed in transmutation – animals changing form over time. The missing piece of the puzzle clicked into place when Darwin read An Essay on the Principle of Population, by Thomas Malthus. Malthus Hypothesized that populations of animals could only increase if the food increased; population growth is kept in check by the limited food supply. This was the clue that Darwin needed.
To Darwin, each individual in a species is competing for scarce resources (food, a mate). Although each animal may look the same to us, there are slight differences between individuals. One may have a longer horn or brighter feathers, and this may give them a better chance to survive. Those animals that survive long enough to reproduce will pass beneficial traits onto their offspring. Over time, these traits may become predominant.
To Darwin, that natural selection was the way that positive traits were passed on to following generations. Individuals who were poorly adapted to survive words die early, and their traits would be lost.
Over time, scientists began to understand that entire species could change based on an environmental pressure. At the time, however, Darwin’s theories were controversial. There was an uproar when Darwin suggested that man and ape share a common ancestor, and editorials and cartoons of the day mocked him.
Darwin also saw that females of each species choose mates based on qualities like beauty or strength. In species where the female selects their mate, like peacocks, the females determine which traits passed on. In the case of peacocks, the males have developed extravagant tails. While these tails are attractive to females, they make the male peacock awkward in flight and more visible to predators. Natural selection should have seen this trait died out, but sexual selection meant that this trait was magnified.
In the end, Darwin was justified. He wasn’t correct on all of his theories. However, most of his theories were based on observation and careful collection of data. These theories have stood the test of time, and remain the single best explanation for the phenomena of evolution. Until further evidence arises, the theory of evolution is here to stay.