Early life
Charles Robert Darwin was born on February 12, 1809, in Shrewsbury, England, into a comfortable family. His father was a physician, and his grandfathers included the potter Josiah Wedgwood and Erasmus Darwin, a physician and writer who had himself speculated about the development of living things. Charles was not an outstanding student at school. He was more interested in collecting beetles, rocks and shells than in classical studies.
He was sent to the University of Edinburgh to study medicine, but he left without finishing, in part because he disliked the surgery of the time. His father then steered him toward Cambridge to prepare for a life as a clergyman, which was a common route for a gentleman with scientific interests. At Cambridge he spent much of his time on natural history and became a student and friend of the botanist John Stevens Henslow. After graduating, he was recommended for a place on a ship that would change his life.
The voyage of HMS Beagle
In December 1831, Darwin sailed from England aboard HMS Beagle, a survey ship under Captain Robert FitzRoy. He was there as a naturalist and as a companion for the captain. The voyage lasted nearly five years, returning in October 1836, and carried him along the coast of South America, to the Galápagos Islands, Tahiti, New Zealand, Australia and elsewhere.
He collected thousands of specimens and kept detailed notes. Several observations stood out to him:
- Fossils in South America. He found the bones of large extinct mammals in the same region where living animals seemed to be smaller relatives of them, which suggested a link between past and present life.
- Geology. He read Charles Lyell’s Principles of Geology, which argued that the Earth had been shaped slowly, by processes like erosion and uplift that can still be seen today. This gave him the sense of long timescales that his later ideas needed. He saw evidence of slow land movement himself, including an earthquake in Chile.
- Island life. On the Galápagos, he noticed that species such as mockingbirds and tortoises differed from island to island. The famous finches are often retold as his big “eureka” moment, but the story is more complicated. He did not at first label which island each bird came from, and the importance of the finches became clearer after he returned, when the ornithologist John Gould examined the specimens.
Years of development
Back in England, Darwin began private notebooks on the “transmutation of species,” the older term for evolution. Around 1838, he read Thomas Malthus’s essay on population, which noted that populations tend to grow faster than food supplies. Darwin realized that in nature this would lead to a struggle for survival, and that individuals with helpful variations would be more likely to leave offspring. This became his idea of natural selection, and a separate article explains how that mechanism works.
He married his cousin Emma Wedgwood in 1839, and the couple eventually settled at Down House in Kent, where they raised their children. Darwin suffered from long periods of poor health, and its cause has never been established with certainty. He worked patiently at home on a huge range of subjects, including an eight-year study of barnacles, which gave him close experience of how much variation exists within a species. He also bred pigeons and corresponded with breeders and naturalists around the world.
He did not rush to publish. Reasons often suggested include wanting more evidence, the controversy that the idea would cause and his own caution. Historians discuss the relative weight of these reasons, and there is no single agreed answer.
Wallace and the publication
In 1858, Darwin received a letter from Alfred Russel Wallace, a naturalist working in Southeast Asia, outlining an idea of evolution through natural selection very much like his own. Friends arranged for papers by both men to be presented together at the Linnean Society of London in July of that year. Darwin then wrote a shorter version of his planned larger work, and On the Origin of Species was published on November 24, 1859.
The book argued that species change over time, that living things share common ancestors and that natural selection is a main driver of change. It used evidence from breeding, geography, anatomy, embryos and fossils. It did not say much directly about humans, but this was discussed immediately. In 1871, he published The Descent of Man, applying the ideas to human origins.
Other work
Darwin wrote on many other topics: coral reefs, the movements of climbing plants, orchids and pollination, the expression of emotions in humans and animals and, near the end of his life, the role of earthworms in soil. These books show his habit of careful experiments and detailed observation, often with simple equipment.
What Darwin did not know
Darwin did not know how traits are passed down. The work of Gregor Mendel on inheritance was not widely appreciated until after Darwin’s death, and the understanding of genes and DNA structure came in the twentieth century. His theory therefore was incomplete in a major way, and later scientists combined it with genetics. That combination, often called the modern synthesis, is the basis of evolutionary biology today. Understanding of inherited traits has grown far beyond his own explanations, though his central argument has held up.
He was also not the first to suggest that species change. Earlier thinkers, including Jean-Baptiste Lamarck, had proposed ideas about it. Darwin’s lasting contribution was a well-supported mechanism and a massive body of evidence.
Later years and legacy
Darwin died on April 19, 1882, and was buried in Westminster Abbey in London. His work reshaped biology and affected many other fields. He is often grouped with other famous scientists whose ideas changed how people understand the world, although he himself was modest and cautious in how he presented his claims. Today, scientists still test, extend and refine evolutionary theory, as they do for any active area of science.