story

Great Scientists and their Inventions

Charles Darwin(1809 – 1882.)

charles darwin

image source: wikimedia commons

Charles Darwin is often cited as the greatest biologist in history. His most famous work, On the Origin of Species, explains the theory of evolution by natural selection, providing numerous supporting examples. Darwin believed that all of life on earth had descended from a common ancestor, whose offspring could vary slightly from the original. Successive generations of life took part in a struggle for existence in which the best adapted variations survived to seed new generations. Less well adapted variations became extinct.

Scientific Results from Darwin’s Voyage

Darwin established that the South American content is gradually rising from the sea. Charles Lyell, whose geology book had influenced Darwin on the voyage, arranged that Darwin should present this work to the Geological Society of London at the beginning of 1837.

At the same meeting Darwin presented specimens of birds he had collected from the Galapagos Islands. Within a week, the ornithologist John Gould examined the specimens and declared the birds belonged to an entirely new group of finches. Darwin had discovered 12 new finch species and a new group of finches.



Earlier Ideas about Evolution

The concept of evolution had been hatched thousands of years before Darwin’s time.

Also, his grandfather, Erasmus Darwin, had made some striking contributions to evolutionary theory, including the idea that all life has a common origin.

Darwin’s Theory

In July 1837 Darwin began keeping a notebook of his thoughts and theories about the variation of plants and animals.

By this time, he had completely accepted that species could evolve (or, to use Darwin’s language, transmute).

He decided he would make his investigation according to the principles of Francis Bacon. He would assemble facts before producing a theory.

In October 1838 he read Thomas Malthus’s work on population, showing that populations increase until food runs out, then crash. There is a struggle for existence. Darwin said that having read Malthus:

By December 1838 Darwin was mulling over how breeders improve domestic animals by selecting the animals with the best qualities. In the natural world the selection is carried out by the environment. The lifeforms best adapted to the environment survive and breed. This is natural selection.


Further Work

In 1868 Darwin wrote The Variation of Animals and Plants under Domestication. Feeling the need to offer a mechanism for heredity, and unaware that Gregor Mendel had already provided it, Darwin incorrectly proposed heredity resulted from a process called pangenesis.

In 1871 Darwin’s The Descent of Manpresented evidence that humans are animals – we are members of the ape family, and are the descendants of apes.

In 1872 Darwin looked at the evolution of human psychology in his book The Expression of the Emotions in Man and Animals, showing there are similarities in human and animal psychology.

The idea that species transmute (evolve) had become accepted by most mainstream scientists by about the time the sixth edition of The Origin of Species came out in 1872.

Death

Charles Darwin died aged 73 on April 19, 1882, of heart failure at his country house. He was buried in Westminster Abbey, London, next to John Herschel whose work had inspired him at university and close to his best friend Charles Lyell, whose work had influenced him greatly. Other scientists buried in Darwin’s vicinity at Westminster Abbey include Isaac Newton, Ernest Rutherford, J. J. Thomson, and Lord Kelvin.


Quotes:

A man who dares to waste one hour of time has not discovered the value of life.

It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change.

We must, however, acknowledge, as it seems to me, that man with all his noble qualities... still bears in his bodily frame the indelible stamp of his lowly origin.