Disclaimer: this maybe gossip and not 100% correct.
Charles Darwin came from a wealthy family in the early 1800’s. he was studying theology in university and collected bird specimens as a hobby. Religion may not have been his first choice, he enjoyed his collecting and enjoyed the pubs of London which were full of whalers coming back with magical stories from far away lands. In the 1830’s, England was trying to figure out new trade routes and to find these out it would be a very long multiple year journey. Captains suffered from the stresses of the job and lacked intellectual stimulation while out and about. An up-tick of captain suicides was prevalent.
Charles, tired of school and fascinated by the natural world, was commissioned to be a companion of a captain on a ship. One of his friends gave him a book called the Principles of Geology as a gift. This was not a church/state sanctioned book, radical at the time. I think the book was the kernel that perhaps there was a different way to perceive the world rather than the religious lens.
On the first voyage, he stopped at a site in Brazil recommended from the Whaler Pub tales. Here he found there really was a skeleton of an ancient sloth. The seed of the theory is starting to germinate.
Ecuador at the time utilized the Galapagos as a convict penal colony. The convicts told him of varying species of tortoise depending on the island. Darwin was thinking the same may be true for Finches and much easier to ship back to England. He spent 19 days collecting species of Finches. The collection was sent back to the University of England ahead of his 2 year journey back. The University started to categorize the birds. Found the species where similar yet different and no two birds were exactly the same.
When Darwin came back, he created a tree of life relating the characteristics between birds. What was the same, what was different.
Out of all of this came his theory of Origins of the Species and the Theory of Evolution.
The world around me 