Charles Darwin & Alfred Russel Wallace. A visit to the Galapagos Islands in 1835 helped Darwin formulate his ideas on natural selection. He found several species of finch adapted to different environmental niches. The finches also differed in beak shape, food source, and how food was captured. Natural selection is the mechanism suggested by Darwin for evolution. Because resources are limited in nature, organisms with heritable characteristics that favor survival and reproduction leave more offspring than their peers, causing the traits to become more common over generations.
<span>Theodore Roosevelt was the 26th U.S. President and lived during the 1800s. He was an author, a soldier and a leader. He saw the world around him based on the many things he learned during his life.</span>
