How did Charles Darwin become interested in science?

Charles Darwin was a biologist. he had the initial theory of natural selection or "survival of the fittest" this was the idea that when an animal was born slightly different from its species (for example a slightly longer neck) and then survived to pass on its genes because it was better adapted to its surroundings (in the case of a longer neck due to being able to reach higher food on trees) that then the offspring of this animal would have the same traits until they became widespread and accentuated in a species.