Charles Darwin was a great British naturalist of the 19th Century who, together with Alfred Russell Wallace discovered the process of Evolution by natural selection.
When Darwin was on the Galapagos islands he found that most or all the islands had their own species of tortoise or finches and he could not understand why a god should have made so many different types. Gradually Darwin came to see that each species evolved to survive under local conditions on the island where it lived.
Darwin did not disprove religion but he showed that Intelligent design is not necessary to explain life and that natural selection explains life better.
Since Darwin sensible people have tended to believe in Naturalism or in Theistic evolution. Young Earth Creationism is more for uneducated or unreasonable people.