Charles Robert Darwin was a British scientist who laid the foundation of modern
evolutionary theory with his views on life development through natural selection.He was born in Shrewsbury, Shropshire, England, on February 12, 1809.After graduating from the elite school at Shrewsbury in 1825, Darwin
attended the University of Edinburgh where he studied medicine.
In 1827 he
dropped out and entered the University of Cambridge in preparation for becoming
a clergyman of the Church of England. While there, Darwin met two important
people in his life: Adam Sedgwick, a geologist, and John Stevens Henslow, a
naturalist. After graduating from Cambridge in 1831, the 22-year-old Darwin was
taken aboard the English survey ship HMS Beagle, mainly because of Henslow's
recommendation, as an unpaid naturalist on an expedition around the world.When the voyage began, Darwin didn't believe that species change through
time, but he did believe in two prevailing ideas of the time. The first theory was
that the earth was 6,000 years old and had remained unchanged except for the
effects of floods and other catastropes.
The second was that organisms were
designed especially for certain habitats and appeared on the earth in their present
form.After reading the works of a noted geologist, Darwin began to change his
ideas. He saw evidence that the earth was much older than 6,000 years. In South
America, he was witness to an earthquake that lifted the land several feet. He
realized that mountains could be built by the action of an earthquake over
millions of years.
He found fossils of marine mammals high up on mountains,
and realized that rocks must have been lifted from the ocean.Darwin also studied plants and animals. On the Galapagos Islands, he
found animals that resembled animals on the South American continent, but not
exactly the same. He understood that they must have come to the islands from
the mainland, and then adapted into new species.
He also observed the plant and
animal life of South America, oceanic islands, and the Far East. He noted many
examples that proved that animals in similar environments didn't always look the
same. For example, the emus of Australia and the rheas of South America are
two very distinct species, but they live in the same basic kind of habitat. Darwin
thought about this, and asked himself the question, if animals were formed for a
specific habitat, why would different species be found in habitats that are so
similar?
After leaving the HMS Beagle and returning to England in 1836, Darwin
began recording his ideas about changeability of species in his Notebooks on the
Transmutation of Species.
Darwin's explanation for how organisms evolved was
brought into sharp focus after he read An Essay on the Principle of Population
by the British economist Thomas Robert Malthus, who explained how human
populations remain in balance. Malthus argued that any increase in the availability
of food for human survival couldn't match the rate of population growth.Therefore, the population had to be checked by natural limitations such as famine
and disease, or by actions such as war.After studying Malthus's essay, Darwin immediately applied his principles
to plant and animal life, and by 1838 he had arrived at his first idea of the
theory of evolution through natural selection. For the next twenty years, he
worked on his theory and other natural history projects.
In 1839, he married his
first cousin, Emma Wedgwood, and soon after moved to a small estate, Down
House, outside of London. There he and his wife had ten children, three of
which died during infancy.Darwin's theory was first announced in 1858 in a paper presented at the
same time as one by a young naturalist named Alfred Russel Wallace. Friends
arranged for the two men to present a paper together before the Linnaean Society
of London.
On November 24, 1859, an abstract of Darwin's theory was published
under the long title of On the Origin of Species by Means of Natural Selection,
or the Preservation of Favoured Races in the Struggle for Life. Darwin's complete
theory was published later in 1859, in On the Origin of Species. Commonly
referred to as "The book that shook the world," the Origin sold out on the first
day of publication and subsequently went through six editions.In this book, Darwin presented his idea that species evolve from a more
primitive species through the process known as natural selection, which works
spontaneously in nature.
Darwin pointed out in his account of how natural
selection occurs, known as Darwinism, that not all individuals undergo changes
and that some changes make the particular animal better suited to particular
environmental conditions. He pointed out that most species produce more eggs and
offspring than ever reach maturity. He theorized that well-adapted animals of a
species have a better chance of reaching maturity and producing offspring tha
