Charles Darwin was an English biologist born on February 12, 1809. Darwin came up with the theory of descent with modification and adaptive radiation when he went on a voyage in the Galapagos islands. He noticed that a common ancestor had evolved into different birds with differently shaped beaks, depending on what there main food source was. for example an island where the main food source was nuts the birds would have thick tough beaks to crack them open. However on a different island with a different food source the birds would have totally different beaks, despite evolving from the same ancestors. When Darwin first returned from his journey his theory were not excepted because he had 2 problems. He could not explain how variation could appear in a population. Darwin also could not display an example of evolution occurring at that time. However Charles Darwin missed a great example right in front of him, the Peppered moth.