The year 2009 marks the 150th anniversary of the publication of Charles Darwin’s book On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life. The book contained two basic ideas: first, that the variety of life on the planet was not specially and individually created, but had been gradually modified from existent forms over millions of years, and, second, that the main mechanism of evolution was the process of natural selection.