... visited places around the world, and Darwin studied plants and animals everywhere he went, collecting specimens for further study. Upon his return to London Darwin conducted thorough research of his notes and specimens. Out of this study grew several related theories: one, evolution did occur; two, evolutionary change was gradual, requiring thousands to millions of years; three, the primary mechanism for ... species occurs randomly and that the survival or extinction of each organism is determined by that organism's ability to adapt to its environment. He set these theories forth in his...

• Word Count: 1206
• Approx Pages: 5
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• Grade Level: High School