In Darwin’s time, most people still believed in the theory of special creation.
This theory stated that Earth and all its living things had been created a few thousand years before and that everything had remained in its original form. Nothing had changed since the moment of creation.
Many religions were based on this belief.
Some scientists disagreed. Two Scottish geologists, James Hutton in 1785 and Charles Lyell in 1830, theorized that Earth was actually many millions of years old.
This opened the door for biologists like Jean-Baptiste de Lamarck of France to suggest that millions of years was plenty of time for animals and plants to evolve into new species.
Lamarck was the first to try to explain, in 1809, how this evolution took place with his concept of “inheritance of acquired characteristics.”
He thought that if a living thing’s body changed during its lifetime, then the change would be passed on to its offspring. This proved to be wrong, but it shows that evolution was a scientific issue before Darwin.
Some trace its origins back to Linnaeus’s classification system, when biologists first became aware of the similarities between species.
The biggest flaw in On The Origin of Species was Darwin’s lack of knowledge of heredity.
Austrian botanist Gregor Mendel discovered the laws of heredity just six years after Darwin’s book was published, but Mendel’s work remained undiscovered until 18 years after Darwin’s death.
Darwin addressed the issue of how humans evolved in The Descent of Man, a book written 12 years after On The Origin of Species.